VIEWS: 17 PAGES: 14 POSTED ON: 12/2/2011
Renal PREP Questions 2007 and 2008 across the chest, abdomen, and pelvis as well as bright red blood from the urethral meatus and a deformity of the left femur. Question 45 You are examining a 5-year-old girl who always has Among the initial major interventions are insertion of an had significant daytime wetting and a history of recurrent urinary endotracheal tube and establishment of two large-bore tract infections. Findings on physical examination are normal intravenous lines. Of the following, the MOST appropriate next except for the presence of a sacral dimple above the gluteal cleft. step is to Her urinalysis reveals a specific gravity of 1.005, pH of 5.5, no A. administer broad-spectrum antibiotics to treat his blood, no protein, and no white or red blood cells. Magnetic contaminated wounds resonance imaging of the spine reveals spinal dysraphism. Of the B. administer tetanus toxoid following, the MOST important next step to determine the cause C. obtain upright abdominal films to assess for ruptured viscus of this child's primary enuresis is to obtain D. order contrast-enhanced magnetic resonance imaging of his A. abdominal computed tomography scan head B. abdominal radiography E. place a Foley catheter into his bladder to monitor urine output C. abdominal ultrasonography D. renal biopsy Question 117 A 4-year-old boy presents for a health supervision E. urine culture visit, and in the course of the visit, his mother discloses that ever since the birth of his 2-month-old sister, the boy has resumed Question 77 You are evaluating a 7-year-old boy for hematuria bedwetting, which had ceased to be a regular occurrence. He is and proteinuria. As part of the evaluation, you measure serum dry during the day and has no stool incontinence. Past medical electrolytes. The serum creatinine is 1.1 mg/dL (97.2 mcmol/L). history reveals that the child has never been hospitalized, had a Of the following, the MOST accurate serum creatinine negative urine culture at age 9 months associated with a fever, measurements for children of normal physical development are and was toilet trained completely at age 3, with only episodic A. 3 months old (mg/dL) [mcmol/L]: 0.3 (26.5); 2 years old bedwetting about once every month. Physical examination reveals (mg/dL) [mcmol/L]: 0.4 (35.4); 7 years old (mg/dL) [mcmol/L]: a happy, playful child whose growth and developmental 1.0 (88.4); 17 years old (mg/dL) [mcmol/L]: 1.0 (88.4) parameters are normal for age and who has a circumcised penis B. 3 months old (mg/dL) [mcmol/L]: 0.6 (53.0); 2 years old and normal findings on scrotal examination. Urinalysis of a (mg/dL) [mcmol/L]: 0.8 (70.7); 7 years old (mg/dL) [mcmol/L]: specimen obtained via clean catch urination shows normal results. 1.0 (88.4); 17 years old (mg/dL) [mcmol/L]: 1.2 (106.1) Of the following, the next BEST step in the management of this C. 3 months old (mg/dL) [mcmol/L]: 0.3 (26.5); 2 years old boy is to (mg/dL) [mcmol/L]: 0.4 (35.4); 7 years old (mg/dL) [mcmol/L]: A. begin imipramine therapy at bedtime 0.6 (53.1); 17 years old (mg/dL) [mcmol/L]: 0.9 (79.6) B. obtain urine for culture and sensitivity D. 3 months old (mg/dL) [mcmol/L]: 0.6 (53.0); 2 years old C. perform renal ultrasonography (mg/dL) [mcmol/L]: 0.4 (35.4); 7 years old (mg/dL) [mcmol/L]: D. reassure the mother that this is most likely a temporary 0.7(61.9); 17 years old (mg/dL) [mcmol/L]: 0.7 (61.9) regression E. 3 months old (mg/dL) [mcmol/L]: 0.7 (61.9); 2 years old E. refer the boy for voiding cystourethrography (mg/dL) [mcmol/L]: 0.8 (70.7); 7 years old (mg/dL) [mcmol/L]: 0.7 (61.9); 17 years old (mg/dL) [mcmol/L]: 0.7 (61.9) Question 125 You are asked to evaluate a 15-year-old boy who presented to the emergency department with gross hematuria Question 93 You have been the primary practitioner for a 15- that began the day before. He ran his first marathon yesterday. year-old girl since she was 3 years old. She never has been He reports no dysuria, urgency, frequency, or abdominal or flank hospitalized, and her history, vital signs, and physical examination pain. His vital signs and physical examination findings are normal. findings on this health supervision visit are normal. At each of the Urinalysis reveals: specific gravity, 1.010; pH, 6.0; large blood; past two yearly visits, urinalysis revealed no abnormalities except no protein; 0 to 2 red blood cells; and 0 to 2 white blood cells. A 2+ protein. Her urinalysis today again reveals 2+ protein with no serum creatinine is 2.7 mg/dL (238.7 mcmol/L). His complete other abnormalities. Her complete blood count, measurements of blood count is normal. Of the following, the MOST likely cause of serum electrolytes and serum complements, and antinuclear his hematuria and renal failure is antibody test results are all normal. Two successive 24-hour urine A. hemoglobinuria collections reveal 321 and 387 mg protein. You now refer the girl B. immunoglobulin A nephropathy to a pediatric nephrologist. Of the following, the MOST important C. myoglobinuria next step for the pediatric nephrologist is to D. urinary tract obstruction A. obtain a first morning urine specimen E. urolithiasis B. obtain renal ultrasonography C. perform a renal biopsy Question 141 You are seeing a newborn boy for the first time. D. repeat the 24-hour urine collection Several prenatal ultrasonographic examinations revealed bilateral E. repeat the urinalysis hydronephrosis. The boy's weight and height are appropriate for gestation, and his physical examination findings are Question 109 An 11-year-old Caucasian boy who has no unremarkable. Postnatal ultrasonography reveals severe bilateral significant past medical history presents to the emergency hydronephrosis. Of the following, the MOST likely cause of the department with a 3-day history of brown urine. He reports no hydronephrosis is dysuria, urgency, frequency, or abdominal or flank pain. His vital A. polycystic kidney disease signs reveal: temperature, 99°F (37.2°C); blood pressure, 141/84 B. posterior urethral valves mm Hg; heart rate, 92 beats/min; and respiratory rate, 24 C. ureteropelvic junction obstruction breaths/min. Significant findings on physical examination include D. vesicoureteral reflux moderate periorbital and leg edema. His urinalysis reveals E. Wilms tumor moderate blood and 4+ protein. The serum complement 3 (C3) and C4 concentrations are both low. Of the following, the MOST Question 147 You are evaluating a very low-birthweight (VLBW) likely cause of his hematuria is preterm infant who experienced polyuria in the first 72 hours after A. immunoglobulin A nephropathy birth. No diuretics have been prescribed, and there is no B. membranoproliferative glomerulonephritis glycosuria, hematuria, or obvious anasarca on examination. You C. postinfectious acute glomerulonephritis collect a urine sample to measure electrolytes and creatinine and D. urinary tract infection simultaneously obtain a blood sample to measure serum E. urolithiasis electrolytes and creatinine. Of the following, the MOST correct statement regarding sodium handling in the VLBW infant is that Question 112 An 11-year-old child is brought to the emergency A. fractional excretion of sodium is lower than in term infants department with massive trauma after a motor vehicle crash. His B. intravenous sodium supplementation is necessary from birth Glasgow Coma Scale score is 3. Rapid assessment reveals marked C. phototherapy increases sodium requirements bruising of the face and blood from the mouth, nose, and ears. In D. sodium excretion increases with gestational age addition, the child has large areas of bruising and abrasions E. water losses generally exceed sodium losses B. congenital nephrotic syndrome Question 157 C. congenital Wilms tumor You are evaluating a newborn boy who has lax abdominal D. oligohydramnios sequence musculature (Item Q157A) and bilateral undescended testes. E. Turner syndrome Other findings on physical examination are normal. Of the following, the MOST likely urologic abnormality in this boy is Question 189 You are seeing a 10-year-old boy and his 13-year- old sister for the first time. When you review the medical records provided by their mother, you find normal medical histories, vital signs, and physical examination results for the children. However, the family history indicates that two of the children's uncles are receiving hemodialysis and are deaf and one grandfather died of kidney disease. You obtain a screening urinalysis (UA) in both children. The boy's UA reveals moderate blood, negative protein, and 20 to 30 red blood cells/high/power field (RBC/hpf); the girl's UA reveals trace blood with 5 to 10 RBC/hpf. Of the following, the MOST accurate statement regarding the prognosis for these children is that A. the boy will develop end-stage renal disease (ESRD); the girl will not develop ESRD A. hydronephrosis B. the chances of developing ESRD are equal in the boy and girl B. renal cysts C. the boy will develop ESRD with hearing deficits; the girl will not C. ureterocele develop ESRD D. ureteropelvic junction obstruction D. the boy will develop ESRD and esophageal leiomyomatosis; the E. vesicoureteral reflux girl will develop only hearing deficits E. the boy will develop ESRD and giant cell thrombocytosis; the Question 163 You are present at the birth of an infant in whom girl will develop only ESRD bilateral hydronephrosis was diagnosed in utero. A fetal shunt was placed in each flank between the renal pelvis and the amniotic Question 195 You are called to evaluate a male infant at 50 cavity. Nonetheless, the infant has bilaterally palpable flank hours of age because he has not voided. He was born at term and masses, and the shunts are not apparent at birth. The infant has breastfed poorly, but has passed stool. He appears shows no dysmorphisms and has no respiratory distress. Renal uncomfortable on physical examination, with a large abdomen ultrasonography reveals bilateral hydronephrosis. Of the and seemingly palpable bladder. There is no respiratory distress. following, the MOST correct statement regarding the The external genitalia are normal, and both testes descended. Of fetus/neonate who has obstructive uropathy is that the following, the MOST appropriate initial step in this infant's A. urinary tract infection, hydronephrosis, and respiratory distress evaluation is all can be treated and resolved with a fetal shunt A. consultation with a urologist B. urinary tract infection, hydronephrosis, and respiratory distress B. intravenous pyelography typically lead to fetal or neonatal death C. nuclear renal scan C. urinary tract infection is common, hydronephrosis often D. passing of a urinary catheter persists, and respiratory distress is not uncommon E. renal ultrasonography D. urinary tract infection is uncommon, hydronephrosis resolves spontaneously, and respiratory distress is uncommon Question 205 A 10-year-old girl presents to the emergency E. urinary tract infection is uncommon, hydronephrosis resolves department with a 1-day history of brown urine. She reports no spontaneously, and respiratory distress results from apnea dysuria, urgency, frequency, or abdominal or flank pain. Her vital signs include: temperature, 98.8°F (37.1°C); blood pressure, Question 173 You are evaluating a 10-year-old boy who has 165/97 mm Hg; heart rate, 84 beats/min; and respiratory rate, intermittent urinary incontinence. Voiding cystourethrography 20 breaths/min. On physical examination, moderate periorbital detects a urethral stricture. Of the following, the MOST likely edema is evident, but there are no other abnormalities. Urinalysis cause of this boy's urethral stricture is reveals moderate blood and 4+ protein. The serum complement 3 A. carcinoma (C3) concentration is low, and the C4 concentration is normal. Of B. chronic infection the following, the MOST likely cause of this girl's hematuria is C. congenital narrowing A. focal segmental glomerulosclerosis D. intermittent urolithiasis B. immunoglobulin A nephropathy E. trauma C. lupus nephritis D. membranoproliferative glomerulonephritis Question 179 An infant is born following a pregnancy E. postinfectious acute glomerulonephritis complicated by no prenatal care and reduced fundal height for gestation on examination during labor. Fetal heart rate tracings Question 221 A 14-year-old boy presents to the emergency are nonreassuring. Physical examination of the infant reveals a department with a 2-week history of bilateral leg edema and a 3- birthweight of 1,800 g, flattened facies (Item Q179A), low-set day history of abdominal swelling. His vital signs are: ears, respiratory distress, a large flank mass on the left, and joint temperature, 98.4°F (36.9°C); blood pressure, 125/67 mm Hg; contractures. Renal ultrasonography documents a single left heart rate, 84 beats/min; and respiratory rate, 20 breaths/min. multicystic and dysplastic kidney; the right kidney is absent. Of Physical examination shows moderate ascites and 2+ leg edema. the following, the BEST explanation for these findings is His urinalysis reveals negative blood and 4+ protein. Serum complement concentrations are ordered and found to be normal. Of the following, the MOST likely cause of his edema and proteinuria is A. immunoglobulin A nephropathy B. lupus nephritis C. membranous nephropathy D. membranoproliferative glomerulonephritis E. postinfectious acute glomerulonephritis Question 222 A 3-year-old boy who has spina bifida has a history of recurrent urinary tract infections (UTIs). He is currently being treated for a UTI. Monitoring laboratory evaluation shows a blood urea nitrogen of 23 mg/dL (8.2 mmol/L) and a creatinine concentration of 1.1 mg/dL (97.2 mcmol/L). Of the following, the A. Alport disease class of antibiotics that is MOST commonly associated with renal of choking. The mother reports that the boy was seen by the toxicity is nephrologist 1 week ago, and because of worsening renal A. aminoglycosides function, he was begun on sodium bicarbonate. Of the following, B. azalides the electrolyte abnormality that BEST explains his current C. carbapenems symptoms is D. cephalosporins A. hyperkalemia E. penicillins B. hypermagnesemia C. hypocalcemia Question 237 A 12-year-old African-American girl presents to D. hyponatremia your office with a 2-day history of gross hematuria. She describes E. hypophosphatemia the urine as brown. She states that she has had an upper respiratory tract infection for about 3 days. She denies dysuria, Question 78 During your evaluation of a 16-year-old boy at his urgency, or frequency. Her vital signs and physical examination health supervision visit, he reports that he had an episode of cola- findings are normal. Urinalysis reveals: specific gravity, 1.025; colored urine associated with an upper respiratory tract infection pH, 6.5; large blood; no protein; too numerous-to-count red 6 weeks ago. The only significant finding on his medical history is blood cells; and 0 to 2 white blood cells. Serum electrolyte mild hearing loss. Today his blood pressure is 112/66 mm Hg. concentrations are normal. Of the following, the MOST likely Urinalysis shows 3+ blood, 2+ protein, and 20 to 50 red blood cause of her gross hematuria is cells per high-power field (RBC/HPF). Other laboratory findings A. focal segmental glomerulosclerosis include: Blood urea nitrogen, 14 mg/dL (5 mmol/L), Serum B. immunoglobulin A nephropathy creatinine, 0.7 mg/dL (61.9 mcmol/L), Albumin, 4 g/dL (40 g/L) C. lupus nephritis Serum complement components (C3 and C4) are normal, and D. membranoproliferative glomerulonephritis antinuclear antibody titers are negative. You discuss these results E. papillary necrosis with his mother, who then tells you that she recalls being told she had blood in her urine. Urinalysis for the child's mother Question 253 A 3-month-old boy is admitted to the hospital for demonstrates 2+ blood with 10 to 20 RBC/HPF. Of the following, evaluation of failure to thrive. His birthweight was at the 50th a TRUE statement about this patient's disorder is that percentile and length at the 75th percentile. Currently, his weight A. boys who have this condition are more likely to develop chronic is below the 5th percentile and length is at the 25th percentile. renal failure than are girls His vital signs and physical examination results are otherwise B. immune complex deposition within the kidney is believed to be normal. He appears well hydrated. Measurement of serum causative electrolytes reveals: sodium, 139 mEq/L (139 mmol/L); C. it is classified as a small vessel vasculitis potassium, 4.7 mEq/L (4.7 mmol/L); chloride, 114 mEq/L (114 D. the biologic defect in the kidney is believed to involve the mmol/L); bicarbonate 12 mEq/L (12 mmol/L); blood urea glomerular epithelial cell nitrogen, 8 mg/dL (2.9 mmol/L); and creatinine, 0.3 mg/dL (26.5 E. the condition typically has an autosomal dominant inheritance mcmol/L). A consulting nephrologist recommends measurement of urine pH (which is 7.5) and urine ammonium (which is 12,000 Question 94 A 6-year-old boy presents with cola-colored urine. mcM/L) (normal,>60,000 mcM/L). Of the following, the MOST His mother reports that he had a sore throat 10 days ago. On likely cause of this child's acidosis is physical examination, his blood pressure is 136/88 mm Hg, and A. inborn error of metabolism he has mild swelling of the face and lower extremities. Of the B. lactic acidosis following, the MOST likely laboratory finding is C. type I (distal renal tubular) acidosis A. low C3 complement value D. type II (proximal renal tubular) acidosis B. normal urinalysis results E. type IV renal tubular acidosis C. positive antineutrophil cytoplasmic antibody titer D. positive antinuclear antibody titer Question 62 A 4-month-old girl presents with fever. Results of E. positive urine culture urinalysis include 50 to 100 white blood cells per high-power field and 3+ bacteria. Urine culture is positive for Escherichia coli. Question 110 An 8-year-old boy presents with tingling in his Ultrasonography reveals hydroureteral nephrosis of the left upper lower extremities. He had been treated surgically for osteogenic pole, and voiding cystourethrography shows a filling defect within sarcoma and remains on a chemotherapeutic regimen that the bladder (Item Q62A). Of the following, in addition to a urinary includes cisplatin. He reports intermittent vomiting and loose tract infection, the infant is MOST likely to have stools during his chemotherapy treatment. Physical examination shows no other findings of note. Among the results of laboratory evaluation are a magnesium value of 0.9 mg/dL (0.37 mmol/L) and a potassium value of 2.7 mEq/L (2.7 mmol/L). Of the following, the MOST likely explanation for this boy's electrolyte imbalance is A. cellular shifting due to changes in pH B. dietary deficiency C. losses due to recurrent diarrhea D. ongoing losses due to vomiting E. urinary losses due to tubular damage Question 126 An 18-month-old female presents with failure to thrive, polydipsia, and photophobia. Her weight is 8 kg and height is 70 cm (both <5th percentile). On physical examination, she appears pale and small for stated age, and she closes her eyes A. bladder diverticulum when you attempt to perform ophthalmoscopy. She has tacky B. posterior urethral valves mucous membranes and capillary refill of 2 to 3 seconds. C. ureteral stone Pertinent findings on laboratory evaluation include: Sodium, 135 D. ureteropelvic junction obstruction mEq/L (135 mmol/L) Potassium, 2.3 mEq/L (2.3 mmol/L) E. ureterocele Chloride, 109 mEq/L (109 mmol/L) Bicarbonate, 14 mEq/L (14 mmol/L) Blood urea nitrogen, 15 mg/dL (5.4 mmol/L) Creatinine, Question 64 A 1-year-old year boy who has chronic kidney 0.3 mg/dL (26.5 mcmol/L) Calcium, 8.4 mg/dL (2.1 mmol/L) disease from posterior urethral valves presents to your office Phosphorus, 2.1 mg/dL (0.68 mmol/L) Magnesium, 1.4 mg/dL because his breathing has been noisy for the past 2 hours. His (0.56 mmol/L) Hemoglobin, 10.5 g/dL (105 g/L) Glucose, 102 usual medications include calcium carbonate and vitamin D. On mg/dL (5.7 mmol/L) Of the following, the BEST test to establish physical examination, you note inspiratory stridor. He has not had the diagnosis is upper respiratory tract symptoms or fever, and there is no history A. a sweat chloride test B. intact parathyroid hormone measurement are normal. Her growth parameters and physical examination C. ophthalmologic examination findings are normal. You prescribe oral trimethoprim- D. urine ammonia measurement sulfamethoxazole. Of the following, the MOST appropriate E. urine chloride measurement additional step to help reduce the incidence of further urinary tract infection is to Question 150 You are evaluating a 17-year-old boy whom you A. begin an evaluation for immunodeficiency have known since early childhood. He is complaining of headaches B. perform renal scintigraphy over the past 2 weeks. He has a history of asthma, which has C. prescribe a stool softener and regular bowel routine been well controlled, and he is an otherwise healthy member of D. prescribe oral oxybutynin the varsity football team at school. He has had a significant E. refer her to a pediatric nephrologist weight gain of 30 lb (13.5 kg) since his visit to you 1 year ago. He denies using illicit or prescription drugs. On physical examination, Question 211 You are evaluating a 12-year-old boy as part of his he appears very muscular and has a blood pressure of 180/120 annual health supervision visit. He has been in good health. His mm Hg. You repeat the measurement using a leg cuff to ensure heart rate is 75 beats/min and blood pressure is 132/82 mm Hg adequate cuff size and obtain the same result. Of the following, using the appropriate-sized cuff. His weight is above the 95th the BEST management plan is percentile, and his height is at the 50th percentile. He has strong A. angiotensin-converting enzyme inhibition as an outpatient pulses at the right brachial and right femoral regions. Of the B. beta blocker therapy as an outpatient following, the MOST appropriate diagnostic evaluation to pursue C. diuretic therapy as an inpatient at this time is D. repeat blood pressure measurement in 1 to 2 weeks A. blood urea nitrogen, creatinine, and electrolytes E. vasodilator therapy as an inpatient B. echocardiography C. radionuclide imaging of the kidneys Question 158 You are evaluating a 10-year-old girl for a health D. renal artery Doppler studies supervision visit. Her weight and height are at the 50th percentile E. urinary drug screen for age, her blood pressure is 108/64 mm Hg, and there are no unusual findings on physical examination. A screening urinalysis Question 218 A mother brings in her 3-year-old daughter shows a specific gravity of 1.030, pH of 6.5, 2+ blood, and no because of daytime urinary incontinence and abdominal pain. The protein. Urine microscopy reveals 5 to 10 red blood cells/high- mother explained that the girl was toilet trained at 2 years of age. power field.Of the following, the MOST appropriate next step is On physical examination, growth parameters and vital signs are A. abdominal computed tomography scan normal, although the girl has mild suprapubic tenderness without B. antinuclear antibody and complement measurement associated costovertebral angle tenderness or sacral dimples. C. blood urea nitrogen and creatinine measurement Urinalysis shows a urine specific gravity of 1.025, pH of 6.5, 2+ D. referral for cystoscopy blood, 1+ protein, 3+ leukocyte esterase, and positive nitrite. E. repeat urinalysis in 2 weeks Urine microscopy demonstrates 5 to 10 red blood cells/high-power field, 20 to 50 white blood cells/high-power field, and 3+ bacteria. Question 173 One of your patients is a 6-month-old boy who Of the following, the MOST likely etiologic agent is had unilateral hydronephrosis detected prenatally. A. Enterococcus faecalis Ultrasonography shows moderate hydronephrosis on the right and B. Escherichia coli a normal left kidney, and voiding cystourethrography shows no C. Klebsiella pneumoniae reflux, with a normal bladder and urethra. During a MAG D. Proteus mirabilis 3/furosemide renal scan, shortly after the furosemide is E. Staphylococcus saprophyticus administered, the infant becomes extremely fussy and difficult to console.Of the following, the MOST likely diagnosis is Question 233 A 4-year-old female presents with fever, chills, A. duplex collecting system with a ureterocele and vomiting. She has had abdominal pain and dysuria for 3 days. B. multicystic dysplastic kidney Her temperature is 104.2°F (40.1°C), and she has left-sided C. nephrolithiasis costovertebral angle tenderness. Laboratory evaluation reveals a D. obstructive uropathy from posterior urethral valves white blood cell count of 18.7x103/mcL (18.7x109/L) with 85% E. ureteropelvic junction obstruction neutrophils, 5% bands, 7% lymphocytes, and 3% monocytes. On urinalysis, the urine specific gravity is 1.025 and pH is 6.5, and Question 188 During the routine examination of a 1-day-old there is 2+ blood, 1+ protein, 3+ leukocyte esterase, and positive term infant, you palpate an abdominal mass. His growth nitrite. Urine microscopy demonstrates 5 to 10 red blood parameters and blood pressure are within normal limits. Of the cells/high-power field, 50 to 100 white blood cells/high-power following, the MOST likely explanation for the mass is field, and 3+ bacteria. Findings on renal/bladder ultrasonography A. bowel duplication are normal. After a 3-day hospitalization for administration of B. multicystic dysplastic kidney intravenous antibiotics, discharge with a prescription for oral C. neuroblastoma antibiotics is planned. Of the following, the MOST appropriate D. renal vein thrombosis study to complete this child's evaluation is E. Wilms tumor A. abdominal computed tomography scan B. cystoscopy Question 203 Voiding cystourethrography in a 9-month-old boy C. intravenous pyelography who has new-onset febrile urinary tract infection reveals grade II D. MAG-3 renal scan with furosemide vesicoureteral reflux (VUR). The parents ask you about their son's E. voiding cystourethrography prognosis. Of the following, you are MOST likely to explain that A. approximately 80% of children who have newly diagnosed Question 241 You are evaluating a 15-year-old girl in your office febrile urinary tract infections have VUR when tested for her annual health supervision visit. She is doing well in school B. once VUR is established, no follow-up radiologic testing is and has no complaints about her health, although she would like indicated to lose weight. She has joined the cross-country running team at C. males have a worse prognosis than females school. She is not receiving any prescription medications but D. referral to urology for ureteral reimplantation is warranted occasionally uses over-the-counter (OTC) cold remedies and E. unilateral grade II reflux has a high likelihood of resolution vitamins. On physical examination, she appears thin but is in no within 5 years of the diagnosis distress. Both her height and weight are at the 25th percentile for her age, although her weight has decreased from the 50th Question 209 You are evaluating a 5-year-old girl who has a percentile 1 year ago. Her heart rate is 100 beats/min and blood urinary tract infection. She has had four lower urinary tract pressure is 145/95 mm Hg. Other findings on physical infections in the last 2 years, all of which resolved completely with examination are normal. Of the following, the MOST appropriate oral antibiotics. She denies symptoms of urgency and frequency. next step is to The only significant finding on her medical history is constipation. A. evaluate for pheochromcytoma with blood and urine testing Results of renal ultrasonography and voiding cystourethrography B. order computed tomography scan of the abdomen C. refer the girl for evaluation of anorexia nervosa D. review the list of OTC medications she has used E. screen for use of anabolic steroids Question 248 A mother brings in her 4-year-old son because his eyelids are swollen. On physical examination, the boy has normal growth parameters, normal blood pressure, bilateral periorbital edema (Item Q248A), and pitting pretibial edema. Laboratory findings include normal electrolyte concentrations, blood urea nitrogen of 14 mg/dL (5 mmol/L), creatinine of 0.3 mg/dL (26.5 mcmol/L), albumin of 1.9 g/dL (19 g/L), and normal C3 and C4 complement values. Urinalysis reveals a specific gravity of 1.030, pH of 6.5, 4+ protein, and 1+ blood, and microscopy demonstrates 5 to 10 red blood cells/high-power field. Antinuclear antibody test results are negative, and serologic tests are negative for hepatitis B A. Diphenhydramine surface antigen, negative for hepatitis C, and nonreactive for B. Furosemide human immunodeficiency virus. A purified protein derivative test C. low-sodium diet is nonreactive after 48 hours. Of the following, the MOST D. Prednisone appropriate treatment for this patient is: E. protein-rich diet Renal PREP Answers 2007 and 2008 Question 45 Answer: C Primary enuresis is defined as the absence of achievement of dryness during the daytime, nighttime, or both. In contrast to secondary enuresis, in which the child experiences a period of dryness after completing toilet training, primary enuresis generally has an anatomic cause. The daytime wetting, history of recurrent urinary tract infections (UTIs), sacral dimple above the gluteal cleft, specific gravity of 1.005 and no other abnormalities on urinalysis, and spinal dysraphism on magnetic resonance imaging reported for the girl in the vignette are consistent with probable spina bifida occulta. The spina bifida may be associated with bladder dysfunction because innervation of the bladder originates from the sacral spine, although some investigators believe that the association may be only an incidental finding. Children who have bladder dysfunction of any cause exhibit dribbling, frequency, and recurrent UTIs due to bladder dyssynergy. This may cause some degree of urinary tract obstruction because bladder emptying is interrupted. Such obstruction can be detected easily by abdominal ultrasonography, which is far more accurate for documenting urinary tract anomalies than abdominal radiography. Abdominal computed tomography scan may be more precise than ultrasonography for some conditions in the urinary tract, but it is far more expensive, and the precision for detecting urinary tract obstruction is generally similar. A renal biopsy is indicated for children who have findings suggestive of primary glomerular disease (eg, proteinuria), but would not be helpful to assess urinary tract anomalies. Finally, although children who have bladder malformation may develop UTIs, the child in the vignette has no symptoms or findings on urinalysis suggestive of a UTI. Moreover, a positive urine culture result will not aid in ascertaining the cause of her primary enuresis. Question 77 Answer: C The kidneys have a full complement of glomeruli and tubules at birth, but the nephrons grow during childhood, with most of the development occurring during the first 2 years. Thus, renal function may require up to 2 years to mature completely. Development of glomerular function is generally complete by age 2 years. Tubular function matures rapidly during the first year after birth, resulting in improved ability to reabsorb sodium, potassium, and water. In turn, the adaptability of the kidney to perturbations of normal body homeostasis (eg, dehydration) is more pronounced after the first postnatal year than during infancy. The level of the mother's serum creatinine generally determines the serum creatinine of the newborn in the first 7 to 10 postnatal days. The serum creatinine is relatively low during infancy and early childhood due to lower muscle mass (Item C77A). Additionally, blood flow to the kidneys is lower in early infancy due to increased peripheral resistance, thus reducing effective renal plasma flow. Taken together, these factors contribute to a lower serum creatinine and a relatively lower glomerular filtration rate (GFR) during early childhood. GFR is determined routinely from the serum creatinine, but there are several other methods to determine the GFR, including inulin clearance and measurement of serum cystatin A. Question 93 Answer: A Detection of proteinuria on routine urine dipstick evaluation is an uncommon but perplexing dilemma for pediatricians because proteinuria may suggest underlying renal disease or may represent a benign condition. It is incumbent on the pediatrician to determine the appropriate steps to be undertaken in a child who has a urine dipstick positive for protein. Among the many benign conditions causing a positive dipstick result for urinary protein are one of the following: a very concentrated urine (specific gravity =1.020), alkaline urine (pH =7.5), or the presence of mucoproteins. In addition, acute illness may result in a small degree of proteinuria. The most important feature of these conditions is that the urinary dipstick result almost never exceeds a reading of 1+. In the absence of these conditions, it is vital to determine if the proteinuria is transient (orthostatic) or fixed. Orthostatic proteinuria (OP) occurs during the daytime but disappears when the person is supine (eg, asleep) for at least 2 hours. Although the exact cause of OP remains controversial, it is a benign condition that requires no follow-up or treatment. Children who have OP cannot have a history of renal disease, hematuria, or edema. In contrast, fixed proteinuria is present at all times of the day, regardless of body position. The teenager in the vignette is asymptomatic and has had several urinalyses (UAs) revealing 2+ protein but no other abnormalities. A negative first morning UA, with a urine protein-to- creatinine ratio less than 0.2, would establish the diagnosis of OP. Prior to referral to the pediatric nephrologist, obtaining a repeat UA within 2 weeks and subsequently obtaining a first morning UA likely would have established the diagnosis of OP, obviating the need for several other unnecessary tests (eg, electrolyte panel, complete blood count, serum complements). Renal ultrasonography may be helpful in detecting a potential urinary tract malformation in some patients who may have proteinuria, but it is not the most appropriate first step. If the patient has a positive (1+ or more) first morning UA result, renal biopsy may be indicated. A 24-hour urine collection (instead of a random protein- to-creatinine ratio) rarely is necessary and does not aid in the diagnosis of OP. Proteinuria has been established firmly for this child, and waiting for results from another daytime UA would only delay the diagnosis. Question 109: Answer: B Gross hematuria is defined as discolored urine. The precise color may aid in establishing an origin of the "blood." It is important to recognize that not all patients suspected of having gross hematuria have red blood cells (RBCs) in the urine. Indeed, the urinalysis in some patients who have presumed gross hematuria may lack RBCs, suggesting the presence of myoglobin, hemoglobin, or porphyrins, all of which may discolor the urine. Additionally, some foods (eg, beets), drugs, or additives (red dye) may discolor the urine. A history should be obtained to ascertain a history of renal disease or urinary tract malformation; the duration of gross hematuria; associated symptoms such abdominal, flank, or suprapubic pain (suggesting an infection or renal malformation); fever (suggesting an infection or renal malformation); fever (suggesting an infection); or the passage of sand, gravel, or stones. The next step in determining the cause of gross hematuria is to obtain a urinalysis to assess for blood, protein, and RBCs. The association of blood and protein in the urine with an elevated blood pressure reported for the boy in the vignette strongly indicates new-onset glomerular disease. The low serum complement values are consistent with acute glomerulonephritis (AGN). Of the options listed, only membranoproliferative GN (MPGN) and postinfectious AGN (PIAGN) result in reduced serum complements, and of these two conditions, the C3 and C4 are reduced only in patients who have MPGN. Although PIAGN is much more common than MPGN, only C3 is low in PIAGN. Patients who have immunoglobulin A nephropathy typically develop recurrent episodes of gross hematuria, but the serum complement values are normal. Patients who have infections may develop gross hematuria, but this is rare and usually is limited to viral cystitis. Finally, gross hematuria is common in patients who have nephrolithiasis, but they usually experience pain and do not develop significant proteinuria or hypocomplementemia. One of the most common causes of gross hematuria in children is hypercalciuria, with or without renal stones. Hypercalciuria usually is idiopathic, but it may be due to causes of hypercalcemia (eg, hyperparathyroidism, malignancy, Addison disease, sarcoidosis, vitamin D therapy) or result from increased urinary excretion of calcium (eg, furosemide therapy, Bartter syndrome, Dent disease [inherited hypercalciuria], distal renal tubular acidosis). Gross hematuria may occur in patients who have sickle cell disease or trait due to intrarenal sickling and sludging. Question 112 Answer: B Tetanus toxoid should be administered to all victims of massive trauma who have contaminated wounds and have not received this vaccine within the past 5 years or whose immunization status is not known. For the patient described in the vignette, the widespread areas of abrasion put him at particular risk for tetanus, much like a burn victim. A patient who has blood at the urethral meatus, as described in the vignette, should be assumed to have a urethral injury. Blind placement of a Foley catheter is discouraged because such action may convert a partial urethral tear into a complete transection. Retrograde urethrography should be performed to evaluate for this injury. Upright abdominal films have no role in the evaluation of a patient who has had massive trauma. The cervical, thoracic, and lumbosacral spine must remain immobilized during the initial management of such patients. Optimal radiologic evaluation of the abdomen in major trauma victims is accomplished by computed tomography. Ideally, this should be performed using both intravenous and oral contrast. Computed tomography of the head, not magnetic resonance imaging, is an important part of this patient's evaluation. Contrast adds no information to the scan, so it should not be administered. Prophylactic antibiotics are not warranted for the patient in the vignette. Even in the case of severe burns, prophylactic antibiotics do not significantly decrease the risk of secondary infections, and they may select for resistant organisms. Question 117 Answer: D Bedwetting (nocturnal enuresis) is primary if the child has never been dry at night. It is secondary when a child has previously sustained dryness at night and subsequently resumes bedwetting. Only 2% to 3% of children who have nocturnal enuresis have a contributing physical problem; most have either diminished bladder capacity (also evidenced by daytime wetting or dribbling) or diminished nocturnal arousal (also evidenced by failure to awaken with wet clothes). This is a maturational problem, and parents should be reassured that the problem generally resolves over time. Essentially, a child who has enuresis is unable to awaken to the sensation of a full bladder or unable to awaken to urinate in the toilet. Secondary enuresis usually represents a "relapse" of physiologic primary enuresis. True regression due to psychological stressors often results in diurnal enuresis or other behavioral regressions. No specific evaluation with laboratory tests or imaging is required for either primary or secondary enuresis other than a clean voided specimen for urinalysis to exclude diabetes and infection. Enuresis may be treated with expectant management. Other treatment modalities include alarms and medications. Alarms may have a better long-term success rate than medications such as desmopressin, imipramine, or oxybutynin. These medications have good short-term success rates but also are associated with more adverse effects. Question 125 Answer: C Because routine screening of urine has become a common practice, many children who are otherwise asymptomatic are being discovered to have microscopic hematuria. For most of these children who have no other urinary findings and are asymptomatic, it is unlikely that an underlying cause will be ascertained. In contrast, determining a specific cause of gross hematuria in children is far more likely. History and physical examination are essential for assessing the child who has gross hematuria. Pertinent information includes the presence of prior renal disease and symptoms such as fever, pain, or edema. The physical examination should focus on probing for edema, bruising, joint swelling, or rashes. Regardless of the findings, a urinalysis is mandatory. Blood and significant (greater than 1+) protein are strongly suggestive of glomerular or interstitial disease. Microscopic analysis of a centrifuged urine specimen is necessary to determine if red blood cells (RBCs) are present. In the absence of RBCs, other causes of a dipstick positive for "blood" include hemoglobin, myoglobin, or porphyrins. The likelihood of myoglobinuria is strong for the boy described in the vignette because of the absence of RBCs in the urine and the antecedent strenuous exercise. He probably has developed acute renal failure due to rhabdomyolysis, myoglobin deposition in the kidney, and urinary tract obstruction. Hemoglobinuria is rare in the absence of hemolysis. Immunoglobulin A nephropathy may present with gross hematuria, but RBCs should be detected on microscopic analysis. Although patients who have urinary tract infections often have microscopic hematuria, gross hematuria is unusual. Finally, patients who have urolithiasis may develop gross hematuria, but concomitant colicky pain is usually present. Myoglobinuria is caused by any process that involves excessive destruction of muscle or rhabdomyolysis. This may occur after excessive, strenuous exercise in hot weather. Other causes of myoglobinuria include crush injury to muscles from trauma, mitochondrial disorders, other inherited muscle diseases (eg, carnitine palmitoyltransferase II deficiency, McArdle disease), malignant hyperthermia, or rarely after systemic viral illness or due to medication usage (eg, HMG-CoA reductase inhibitors). Question 141 Answer: B Urinary tract obstruction (UTO) may indicate an abnormality in the kidney(s), ureter(s), bladder, or urethra. A logical and stepwise approach to determine the cause usually results in reaching an accurate diagnosis. UTO generally is found in utero or early in infancy. The advent of routine fetal ultrasonography has dramatically increased the detection of UTO prior to birth. In most other cases of UTO, a urinary tract infection in infancy stimulates evaluation of the system. The practitioner's goal is to ascertain the site of obstruction. Renal ultrasonography is the primary imaging technique used to determine if UTO is present, and if so, the degree of obstruction. In general, hydronephrosis is described as mild, moderate, or severe. Most studies show that renal function is better preserved in mild compared with moderate-to-severe hydronephrosis. Another invaluable piece of information is whether the hydronephrosis is unilateral or bilateral. Obviously, bilateral hydronephrosis increases the likelihood of developing renal insufficiency, but it also may provide an indication of the origin of obstruction. Generally, the origin of obstruction is lower with bilateral versus unilateral hydronephrosis. It is essential to determine the cause of any obstruction; if left untreated, it may result in recurrent urinary tract infections and renal scarring and damage. The bilateral hydronephrosis reported for the boy in the vignette strongly suggests the presence of UTO, although the hydronephrosis may be nonobstructive. Voiding cystourethrography is necessary to determine if there is vesicoureteral reflux (VUR) (Item C141A), a ureteral abnormality such as a duplicated ureter, or posterior urethral valves (PUV) (Item C141B). PUV must be considered a likely cause of bilateral hydronephrosis in a male. The most common presentation of autosomal recessive or dominant polycystic kidney disease (Item C141C)is enlarged kidneys in the newborn period, with or without small cysts; these kidneys do not display hydronephrosis. Although ureteropelvic junction obstruction (UPJO) and VUR commonly cause hydronephrosis, the sex of the child and bilateral hydronephrosis makes PUV more common. However, it should be emphasized that children who have PUV may have concomitant VUR or UPJO. Wilms tumor (Item C141D), the most common abdominal tumor in infants, presents most commonly as a solid mass, occasionally with concomitant hydronephrosis. Question 147 Answer: E The fractional excretion of sodium (FENa) is a measure of renal handling of solute. The equation for calculating the FENa is: FENa = [(Urine Na x Plasma Cr)/(Plasma Na x Urine Cr)] x 100 Example: [(90 x 0.9)/(145 x 120)] x 100 = 0.5 Sodium is reabsorbed in the proximal renal tubule. In the preterm kidney, a number of factors affect the renal handling of sodium. First, the renal blood flow increases throughout gestation in the fetus and in the first week of postnatal life. Second, the glomerular filtration rate increases throughout the first postnatal week. Third, the extracellular fluid compartment, where most of the total body content of sodium is located, is greatest in the most preterm infants. Depending on the degree of prematurity, the functional number of nephrons may be reduced significantly (nephrogenesis is not complete until after 36 weeks' gestation), and renal efficiency in handling solute load is reduced accordingly because sodium transporter activity in the renal tubules is immature. Additionally, the premature kidney has poor concentrating ability, with maximal urinary concentration of 600 to 800 mOsm/L in the first 2 weeks of postnatal life. This results in a high risk of hypervolemia and hyponatremia (due to dilution) for the preterm infant who is given too much water. However, because of postnatal adjustments in fluid compartments (Item C147A), the addition of sodium to intravenous fluids for the preterm neonate is largely unnecessary in the first 24 to 72 hours after birth. The very low-birthweight (VLBW) newborn described in the vignette has polyuria, generally defined as a urine output of greater than 6 mL/kg per hour. Causes typically include iatrogenic overhydration, diabetes insipidus (genetic or sometimes related to intracranial pathology), hyperglycemia with a corresponding osmotic drag of water and the occurrence of glycosuria, or anatomic renal problems such as an obstruction that has been relieved. Water losses in the VLBW newborn generally exceed solute (sodium) losses, especially in cases of polyuria, and dehydration with elevated serum sodium concentrations may result. As noted previously, sodium excretion (FENa) decreases with increasing gestational age and postnatal age. Accordingly, the FENa is higher in a preterm newborn than in a term infant. Phototherapy increases fluid (water) requirements for the VLBW newborn, but not sodium requirements. Intravenous sodium supplementation is not necessary in most VLBW newborns in the first 24 to 72 hours of postnatal life. Question 157 Answer: A Prune belly (Eagle-Barrett) syndrome (PBS) is a relatively uncommon condition resulting from poorly developed abdominal musculature. Affected children may have a variety of urinary tract anomalies, including undescended testes, hydronephrosis, posterior urethral valves (PUV), and bladder dysfunction. The lax abdominal musculature (Item C157A) and bilateral undescended testes described for the boy in the vignette suggest the diagnosis of PBS. Abdominal ultrasonography and voiding cystourethrography are indicated in all children who have PBS to study the entire urinary tract. Hydronephrosis is a common anomaly associated with PBS. The hydronephrosis usually is obstructive and due to PUV or vesicoureteral reflux and ureteropelvic junction obstruction. Renal cysts are very uncommon, and ureteroceles are seen only occasionally in children who have PBS. Some affected children may have nonobstructive hydronephrosis. The best test to differentiate obstructive from nonobstructive hydronephrosis is renal scintigraphy. In obstructive hydronephrosis, the tracer cannot escape the kidney, but in most kidneys with nonobstructive hydronephrosis, some amount of the tracer exits the kidney. The renal outcome for children who have PBS is generally poor. Meticulous attention must be paid to the prevention of urinary tract infections (UTIs). Thus, it is imperative to institute antibiotic prophylaxis if obstruction is present, and in some cases of moderate-to-severe hydronephrosis with obstruction, early surgical repair is recommended. Urinary diversion via a vesicostomy or Mitrofanoff procedure (using the appendix to connect the bladder to the abdomen, with exit near the umbilicus) may be indicated to prevent urinary stasis and UTIs. Unfortunately, renal growth usually is compromised because of multiple abnormalities within the urinary tract, and most children who have PBS develop renal insufficiency. Question 163 Answer: C The infant described in the vignette has a prenatal diagnosis of hydronephrosis and palpably enlarged kidneys on physical examination. Despite a history of shunting in utero, there are no apparent shunts present on examination. Because this is not uncommon when upper urinary tract obstruction is the problem, present techniques generally address direct drainage of renal calyces or cysts by needle under ultrasonographic guidance. Hydronephrosis in the fetus, which may be physiologic and transient, or pathologic, is observed in 1 in 500 to 700 fetuses. Pathologic obstructive uropathy most frequently results from ureteropelvic junction obstruction or, less commonly, ureterovesical obstruction. In males, the most common lower tract cause of obstructive uropathy is posterior urethral valves (Item C163A). Obstruction of the emptying of the renal collecting system, ureters, or bladder may result in retrograde hydrostatic pressure and destruction of the renal parenchyma. Rupture of the fetal urinary collecting system under these conditions is believed to cause urinary ascites. When an obstruction is identified in a fetus, a vesicoamniotic shunt to relieve pressure and preserve renal function may be considered. The optimal timing of delivery may be determined in balancing the effects of oligohydramnios and pulmonary hyperplasia against progressive renal parenchymal loss. Unfortunately, efforts to mitigate the obstruction and consequential renal impairment by placing shunts have not met with great success. Fetal shunts may become dislodged or obstructed, the accumulation of urine continues, and their placement imposes risks of preterm labor and chorioamnionitis. Amniotic fluid volumes may be diminished in the presence of fetal urinary tract obstruction, which may, in turn, lead to impaired fetal lung development, especially if the amniotic fluid volume is reduced during the canalicular stage of lung development (16 to 24 weeks' gestation). Postnatal death from pulmonary hypoplasia is well described in affected patients. Although certain fetuses who have lower urologic obstructions may benefit from vesicoamniotic shunting, patient selection is difficult, and no large randomized trials have demonstrated clear benefit. At present, placement is reserved for fetuses whose delivery is not imminent and who have a high risk for pulmonary hypoplasia due to the presence of oligohydramnios. Postnatally, infants who have obstructive uropathy are at increased risk for urinary tract infection, vesicoureteral reflux, hydronephrosis, and possibly respiratory distress, but these conditions do not typically lead to fetal or neonatal death. Respiratory distress may be related to impingement of renal masses on the diaphragm, urinary ascites, or an element of pulmonary hypoplasia. Although simple, transient, physiologic hydronephrosis may resolve spontaneously, obstructive uropathy does not. Question 173 Answer: E Urethral stricture disease involves blockage or narrowing of the urethra that causes reduced urine flow during voiding. Most urethral strictures occur in males. The most common causes in children are previous trauma (eg, posterior urethral injury occurring as a consequence of pelvic fracture) or instrumentation of the urethra, infection (eg, gonorrhea), congenital anomaly, idiopathic, and as a complication of balanitis (balanitis xerotica obliterans). Children who have urethral strictures can develop a variety of signs and symptoms, including straining to urinate, a decrease in the size and force of the urine stream, persistent sense of bladder fullness, urine dribbling, and frequency and urgency of urination. Overt physical examination findings are generally absent. Diagnosis is confirmed by cystoscopy. Alternatively, voiding cystourethrography can be performed to determine the extent of the stricture or ultrasonography may be performed. Treatment of a urethral stricture depends on the length, location, and persistence of the stricture. In general, initial urethral strictures that are short (<1.5 cm) can be treated with either endoscopic incision or dilation. Although this form of treatment has only a modest success rate, it is minimally invasive and associated with few procedure-related complications. Recurrent strictures or strictures longer than 2 cm usually are not amenable to endoscopic incision or dilation, and this form of therapy proves to be a "temporizing" measure without much long-term success. Severe urethral stricture in males may damage the bladder and cause hydronephrosis. Carcinoma of the urethra is rare in children, and the boy described in the vignette has no history of chronic infection. Moreover, chronic gonorrhea is uncommon at this age. The boy's age effectively eliminates congenital narrowing as a cause; symptoms usually develop in early childhood. Chronic intermittent urolithiasis is a very rare cause of urethral stricture, especially in patients who have no history of chronic abdominal or flank pain. Question 179 Answer: D The infant described in the vignette is growth-restricted, has a flank mass consistent with an enlarged kidney, and has the characteristic phenotype of the fetal oligohydramnios sequence. Bilateral renal aplasia (true Potter syndrome), which occurs in 1 per 3,000 births, or severe dysplasia, such as that seen in multicystic dysplastic or hereditary polycystic kidney disease and resulting in oligohydramnios (Potter sequence), both jeopardize fetal and neonatal well-being. Renal aplasia/dysplasia in the fetus results in oligohydramnios that alters amniotic fluid dynamics and interrupts normal development of the fetal lung, especially during the canalicular stage of lung development from 16 to 24 weeks' gestation. Pulmonary hypoplasia results and may prove fatal in the neonatal period despite efforts at assisted ventilation. An additional complication of this aberrant renal development is reduced intrauterine volume, resulting in fetal constraint. In such instances, the growth restriction is generalized, the facies is flattened (Item C179A), the ears appear low-set, the arms and legs may be malpositioned with clubbing of the feet (Item C179B) and joint contractures, and breech presentation is not uncommon. Alport disease is an inherited condition (X-linked in 85% and autosomal recessive in 15%) that involves the kidneys, cochlea, and eyes, leading to sensorineural deafness and nephritis. The defect affects type IV collagen, and clinical stigmata do not present in the newborn period. Congenital nephrotic syndrome is characterized by edema, ascites or hydrops, and associated proteinuria, hyperlipidemia, and hypoalbuminemia. It is most common among families that have Finnish ancestry. Wilms tumor, also known as a mesoblastic nephroma, may be congenital and may be associated with aniridia, hemihypertrophy, or Beckwith-Wiedemann syndrome. Findings on the physical examination include hypertension, hematuria, and a flank mass. Turner syndrome is due to an absence of part or all of one of the X chromosomes. Renal anomalies seen in this condition include renal aplasia or hypoplasia, rotated or horseshoe kidneys, or renal duplication. The clinical phenotype includes growth restriction, lymphedema of the dorsal aspects of the hands and feet, cystic hygroma, and cardiovascular defects such as coarctation of the aorta and other left-sided cardiac outflow tract lesions. Question 189 Answer: C Alport syndrome (hereditary nephritis) is an uncommon disease, affecting about 1 in 5,000 persons. There are several modes of inheritance, the most common being X-linked. Although there is a male-to-female ratio of 1:1, men are affected earlier and more severely than women. Other modes of inheritance include autosomal dominant, autosomal recessive, and heterogeneous. Females who have the defective gene on one of their two X chromosomes usually are asymptomatic, although they may exhibit some degree of minor renal insufficiency; most females who have Alport syndrome have some blood in the urine. Males who have the defective gene usually develop renal failure between the second and third decades of life. In most cases, the mutation lies in abnormal collagen type IV (COL4A) protein that is an essential part of the glomerular basement membrane. Other conditions that may be inherited and present with hematuria, such as benign familial hematuria and thin membrane disease, are associated with significantly more favorable renal outcomes than is seen with Alport syndrome. The primary characteristics of Alport syndrome are progressive renal failure, sensorineural hearing deficits, and abnormalities of the lens of the eye (lenticonus). Uncommon associated conditions include immunologic abnormality of skin, disorders of platelets, abnormalities of white blood cells, and smooth muscle tumors. Alport syndrome can be diagnosed by several methods. Most commonly, it is diagnosed initially by testing the urine (for blood) of persons who have an affected family member. The urine result may be confirmed by performing a kidney biopsy and assessing for the presence or absence of the COL4A protein. In certain cases, testing for the abnormal gene in Alport syndrome may be performed. The strong family history of renal disease with associated hearing deficits reported for the boy in the vignette is very suggestive of Alport syndrome. Based on the usual mode of inheritance, it can be assumed that the boy will develop end-stage renal disease, but his sister may develop only minor kidney disease or simply be a carrier of the gene. The family history suggests that the boy likely also will develop some degree of hearing deficits. Unusual associated anomalies, including esophageal leiomyomatosis and giant cell thrombocytopenia, are seen only occasionally in Alport syndrome and usually are associated with autosomal modes of inheritance. The family history indicates that this boy has inherited the disease through an X-linked pattern. Question 195 Answer: D The causes of acute renal failure (ARF) in the newborn include: dehydration, sepsis, congestive heart failure, toxic effects of certain drugs (angiotensin-converting enzyme inhibitors, indomethacin, amphotericin), acute tubular necrosis, congenital renal dysplasia, renal vein thrombosis, and obstructive uropathies (posterior urethral valves, neurogenic bladder, bilateral ureteropelvic junction or ureterovesical junction obstruction). The infant described in the vignette, who has not passed urine 50 hours after birth and who has a palpably full bladder, should be evaluated thoroughly. Anuria in a newborn for more than 24 hours warrants an evaluation that includes a thorough history (including obstetric history and drug exposure), review of any prenatal ultrasonography images, assessment for evidence of perinatal asphyxia or sepsis, and a family history of renal disease. The physical examination should address the genitalia, abdomen, and flanks as well as any signs of edema or oligohydramnios sequence. Laboratory evaluation should attend to serum electrolytes, urea nitrogen and creatinine, urinalysis, urine culture, and urinary electrolytes and creatinine. To obtain urine and complete the evaluation of the patient, a urinary catheter must be placed. Doing so will answer two questions:Are the urethra and bladder outlet patent or obstructed? Have the kidneys produced any urine? Once urine is obtained, the laboratory evaluation can be completed and a fractional excretion of sodium (FENa) calculated to assist in distinguishing prerenal ARF (FENa ≤1.0) from intrinsic ARF (FENa >1.0). If no urine can be obtained by catheterization, ultrasonography of the kidneys, ureters, and bladder should be performed. Neither nuclear renal scan nor intravenous pyelography should be performed until urine flow is established. A urologist may be consulted, but bladder catheterization should be performed first. Question 205 Answer: E The girl in the vignette has painless gross hematuria without fever. Fever would suggest possible infection, and abdominal pain would hint at infection, stone, or renal malformation (tumor, cyst). She has an elevated blood pressure and periorbital edema, which may be due to hypoalbuminemia or fluid retention. Her urinalysis shows blood and protein. The most significant clue to the cause of her renal disease is her low serum complement 3 (C3) concentration and normal C4 concentration. She has strong evidence of nephritis (gross hematuria, hypertension, periorbital edema), decreased C3, and normal C4 values, which are consistent with postinfectious acute glomerulonephritis (PIAGN). If both the C3 and C4 values were low, the nephritis more likely would be membranoproliferative GN or lupus nephritis. Children who have either focal segmental glomerulosclerosis or immunoglobulin A nephropathy may develop gross hematuria, hypertension, edema, and nephritis, but because of the pathogenesis of these diseases, the serum complement values would be normal. PIAGN is a common but generally self-limited renal disease that usually occurs in childhood. Among the several known pathogenetic organisms associated with PIAGN, the most common is group A beta-hemolytic Streptococcus. Most children who have PIAGN recover complete renal function and exhibit normalization of C3 levels by 6 weeks, although some continue to exhibit hematuria and/or proteinuria for prolonged periods after initial presentation. Some also have hypertension, primarily due to salt and water retention, for up to 3 months. Occasionally, the disease may assume a rapidly progressive course, resulting in acute renal failure and the need for treatment with high-dose intravenous corticosteroids and possibly intravenous cyclophosphamide or dialysis if renal failure persists. In these patients, the renal outcome is guarded. Question 221 Answer: C Nephrotic syndrome (NS) is a constellation of symptoms that include proteinuria, hypoalbuminemia, edema, and hyperlipidemia. The most important aspect is proteinuria; the other symptoms simply are outcomes of excessive urinary protein leak. Proteinuria is not the only cause of hypoalbuminemia; other causes include advanced liver disease, severe malnutrition, and gastrointestinal losses. If NS is suspected, a urinalysis may provide clues to the cause. Among the many causes of NS in children, the most common are minimal-change NS (MCNS), focal segmental glomerulosclerosis (FSGS), membranous nephropathy (MN), any cause of acute glomerulonephritis (AGN), membranoproliferative GN (MPGN), lupus GN, and immunoglobulin A nephropathy (IgAN). The practitioner's goal is to determine the cause of NS to devise the best management plan. Although most glomerular diseases are not inherited, a family history of renal disease may suggest FSGS, LN, or IgAN. Urinalysis may be helpful, with the presence of blood making MCNS, FSGS, and MN less likely, although any of these conditions may feature protein and blood in the urine. Measuring serum electrolytes is essential to determine overall renal function in any child who has NS, but it is unlikely to provide any clues to the cause. An important clue may be obtained by assessing serum levels of complement 3 and 4. Normal serum complement values, as reported for the boy in the vignette, generally eliminate postinfectious AGN, MPGN, and Tupus nephritis due to Henoch-Schönlein purpura as the cause of NS. The older age of the boy described in the vignette, absence of hematuria, and normal serum complement values suggest MN as the most likely cause of his renal disease. Another common cause could be FSGS. MCNS is most common in toddlers and early school-age children; MN, MPGN, and IgAN generally present in older (>10 years of age) children. Question 222 Answer: A Multiple antibiotic classes can cause renal toxicity, but the class that is the most likely to cause nephrotoxicity is the aminoglycosides (gentamicin, tobramycin, amikacin, streptomycin, and kanamycin). The renal toxicity of these agents is related to their concentrative uptake by the proximal renal tubular cells and their capacity to interact with critical intracellular targets. Risk factors associated with the development of such nephrotoxicity include prolonged course of therapy, supertherapeutic doses, concurrent use of other nephrotoxic medications, dehydration, and underlying liver disease. The development of nephrotoxicity is characterized by the gradual onset of partial-to-complete, reversible, nonoliguric renal failure. The patient may exhibit hypertension, and laboratory evaluation demonstrates elevations in blood urea nitrogen and creatinine values as well as elevated protein concentrations on urinalysis. Nephrotoxicity rarely is associated with the other antibiotics listed. Question 237 Answer: B Immunoglobulin A nephropathy (IgAN) or Berger disease is the most common cause of primary glomerulonephritis in adults in the world. In contrast, only about 5% to 10% of children who have glomerular disease exhibit IgAN. Although once considered to be a random disease with no genetic component, the prevailing opinion now is that there may be a strong familial component to IgAN. The pathogenesis of IgAN remains elusive. It is not a classically defined autoimmune disease, although the disease develops from deposition of IgA-containing immune complexes in the kidney. It is tempting to assume that the pathogenesis is related to mucosal IgA because the disease often follows an upper respiratory tract infection, but deposited IgA is predominantly polymeric IgA1. The association of some cases of IgAN with syndromes that affect the respiratory or gastrointestinal (GI) tracts supports the relationship between IgAN and the immune system. Moreover, it has been shown that the gross hematuria worsens during or after upper respiratory tract or GI infections. Serum IgA concentrations may be elevated in about 50% of patients who have IgAN, making this finding relatively nonspecific and not diagnostic. The natural history of the disease varies. About one third of patients have a benign course, one third experience slow progression to renal failure, and one third have a more progressive course in which renal failure develops within 20 years. IgAN is more common in whites and Asians than other ethnic groups and is observed frequently in American Indians. IgAN is more common in males than females. The girl in the vignette has the classic presentation of IgAN: a brief history of painless, gross hematuria following an upper respiratory tract infection. Her urinalysis demonstrates too numerous-to-count red blood cells but no protein, and her renal function is normal. Children who have focal segmental glomerulosclerosis may develop gross hematuria, but this is not common. Patients who have lupus nephritis may develop either microscopic or gross hematuria, but they often have associated symptoms (eg, rashes, arthritis, anorexia). Children who have membranoproliferative glomerulonephritis may develop gross hematuria, but they often present with proteinuria, edema, and hypertension. Finally, children who have papillary necrosis usually have sickle cell disease or trait, and the gross hematuria generally is associated with pain, typically abdominal or flank pain. The follow-up of a patient who has IgAN includes at least quarterly assessment of urine protein by urinalysis and determination of a random protein-to-creatinine ratio (P/C). A rising urine P/C is highly predictive of progressive renal disease. Frequent measurement of serum electrolyte values is vital, especially for patients who have evidence of significant proteinuria or hypertension. Treatment typically begins with agents to reduce proteinuria: angiotensin-converting enzyme inhibitors or angiotensin receptor blockers. Oral corticosteroids may be effective in some cases but generally do not alter the final outcome significantly. Use of calcineurin inhibitors such as cyclosporine or mycophenolate mofetil has been shown to slow the progression of IgAN in adults, but larger trials are necessary to determine their efficacy fully. Question 253 Answer: C The infant described in the vignette presents with failure to thrive, and measurement of his serum electrolytes reveals a normal anion gap and hyperchloremic metabolic acidosis. The key element in his presentation is the urine pH, which is 7.5, indicating that it is highly alkaline. In proximal renal tubular acidosis (RTA), as the urine leaves the proximal tubule, the relative inability to reabsorb bicarbonate results in a very alkaline pH of the tubular fluid. However, the distal tubule in patients who have proximal RTA is healthy, and it extrudes high quantities of acid, dropping the tubular pH to a lower value (=6.0). In contrast, because the distal nephron represents the last real opportunity for the kidney to regulate acid-base balance, children who have distal RTA cannot adequately compensate for the lack of acid extrusion, resulting in very alkaline urine. The urine ammonium value in the child in the vignette is very low at 12,000 mcM/L (normal >60,000 mcM/L), which is consistent with reduced acid (as part of ammonium) secretion and strongly predictive of distal RTA. RTA is a common cause of metabolic acidosis in childhood. There are two primary types of RTA: proximal or type II and distal or type I. Type IV RTA, also called hyperkalemic RTA, is uncommon and will be discussed only briefly. A review of basic renal physiology in the maintenance of acid-base balance is necessary to understand RTA. The primary responsibility of the proximal tubule in the preservation of normal acid- base homeostasis is to reabsorb filtered bicarbonate. It achieves this goal by reabsorbing water and carbon dioxide from the renal (apical membrane) tubule into the cell and then converting them to hydrogen and bicarbonate within the cell. Hydrogen is extruded back into the tubule, and bicarbonate is reabsorbed at the other end (basolateral membrane) of the cell. Thus, the reabsorption of base (bicarbonate) is linked with the expulsion of acid (hydrogen). In contrast, the primary role of the distal tubule is to secrete acid, either as free hydrogen ion, as part of ammonium (ammonia plus hydrogen), or linked to phosphorous. The distal nephron does play a role in bicarbonate reabsorption, but its primary role is to secrete acid. Because children who have proximal (type II) RTA have difficulty reabsorbing bicarbonate, the serum bicarbonate concentration falls, resulting in acidosis. In distal (type I) RTA, the distal tubule struggles to secrete acid. This excess acid must be buffered in the blood, principally by bicarbonate, which also results in a decline in the serum bicarbonate or acidosis. In distal RTA, there may be concomitant proximal tubule disturbances. The level of the serum bicarbonate in either proximal or distal RTA may vary, depending on the extent of the deficit. To maintain electroneutrality in RTA, the loss of bicarbonate is compensated by the retention of chloride, also a negatively charged ion. Thus, the anion gap ([sodium]-[chloride + bicarbonate]) is maintained at 10 to 16. In other types of acidosis, such as lactic acidosis, the excess accumulation of acid does not induce an increase in chloride absorption and, thus, the anion gap is elevated. Given the normal anion gap, this child cannot have either an inborn error of metabolism or lactic acidosis, which typically results in a high (>16) anion gap. Additionally, the normal serum potassium value effectively eliminates type IV RTA as a cause of the acidosis because the lack of aldosterone or renal resistance to aldosterone in this condition induces acidosis and hyperkalemia. Question 62 Answer: E A ureterocele is a cystic dilation of the ureter where it inserts into the bladder. An intravesical ureterocele is contained entirely within the bladder. When a portion of the defect extends beyond the bladder (to the urethra or bladder neck), an extravesical ureterocele is present. Typically, the pelvocaliceal system draining into the ureterocele is obstructed. The incidence of ureteroceles in children is estimated between 1 in 5,000 and 1 in 10,000. Ureteroceles are associated with a duplex collecting system in 80% of children; the remainder are associated with a single collecting system. Ureteroceles are four times more common in females than males and occur almost exclusively in Caucasians.A ureterocele is associated most commonly with a complete duplication of the renal collecting system (more common in the left kidney) where the involved ureter is linked to that draining the upper pole moiety. This lesion, which extends beyond the ureterovesical junction, results in ureteral obstruction, with hydroureteral nephrosis of the involved renal unit, usually the upper pole, as described for the infant in the vignette. A ureterocele often results in a mass lesion within the bladder that may be seen on bladder ultrasonography or indirectly as a filling defect of the bladder on voiding cystourethrography (Item C62A). The lower pole of the kidney of a duplex collecting system may drain into an orthotopic site and is associated with vesicoureteral reflux (VUR) in approximately 50% of cases. In addition, VUR is seen in approximately 25% of the kidneys contralateral to the duplex kidney that has a ureterocele. Ureteroceles most commonly are associated with urinary tract infection in infants, although 25% are detected antenatally. Older children present with voiding symptoms or hematuria associated with minimal trauma. Surgical treatment is aimed at relieving the obstruction, preserving the functioning nephron mass, removing nonviable tissue that may result in infection, and treating VUR. Based on patient symptoms, treatments include upper pole nephroureterectomy, endoscopic incision of the ureterocele for relief of obstruction, and clinical observation. Ureteropelvic junction obstruction (Item C62B), ureteral stones (Item C62C), and posterior urethral valves (Item C62D) cause hydronephrosis that involves the entire kidney, not just a portion, as is seen with a ureterocele. In addition, in posterior urethral valves, the hydronephrosis is bilateral. A bladder diverticulum (Item C62E) results in an outpouching of the bladder wall without a filling defect in the bladder. Question 64 Answer: C Serum calcium and 1,25 dihydroxyvitamin D concentrations are decreased in children who have chronic kidney disease because of phosphate retention and impaired hydroxylation of 25-hydroxyvitamin D. Physiologic serum calcium concentrations are maintained largely through the use of vitamin D supplements and phosphate binders. As renal function worsens, hypocalcemia can result if vitamin D deficiency or hyperphosphatemia is not addressed or if the use of bicarbonate therapy to treat metabolic acidosis leads to metabolic alkalemia. Metabolic alkalemia increases the binding of calcium to albumin, which decreases the ionized calcium concentration. Decreased ionized calcium can lead to perioral or extremity paresthesias, carpopedal spasm, laryngospasm, and seizures. Children who have hypocalcemia from any cause may be diagnosed mistakenly with croup if they present with tetany-related laryngospasm. Hyperkalemia may lead to muscle weakness and paresthesias and abnormalities in cardiac conduction. Clinical manifestations usually are preceded by conduction abnormalities, which may result in ventricular fibrillation and asystole. Hypermagnesemia generally is not associated with clinical symptoms. Severe hypophosphatemia can cause proximal muscle weakness, cardiac dysfunction, ataxia, seizures, and coma. Hyponatremia is a cause of nausea, vomiting, hypothermia, lethargy, agitation, headache, and seizures. Question 78 Answer: A The adolescent male described in the vignette has hematuria and proteinuria documented on a health supervision visit and a history of cola-colored urine temporally associated with an upper respiratory tract illness 6 weeks earlier. Such findings suggest the presence of an underlying glomerulonephritis that can range from overt disease with gross hematuria when accompanied by an intercurrent illness to a subclinical state with persistent abnormal urinary findings.The evaluation of a child who has glomerulonephritis should begin with careful measurement of blood pressure and renal function (serum creatinine) to assess the severity of the clinical situation, followed by a serologic evaluation to screen for an underlying cause. The normal complement components C3 and C4 described for this boy suggest three likely diagnostic possibilities: immunoglobulin A glomerulonephritis, pauci-immune vasculitis, or familial nephritis. The discovery of hematuria in the mother suggests familial nephritis.Familial nephritis can be caused by either Alport syndrome (AS) or thin glomerular basement membrane (GBM) disease. Both disorders involve underlying defects of the GBM that result in a disruption of the glomerular capillary barrier. This barrier is comprised of the glomerular endothelial cell, the GBM, and the podocyte (visceral glomerular epithelial cell). Any disruption to this barrier permits access of restricted substances, such as red blood cells or protein, to the urinary space. AS is not caused by immune complex deposition, small vessel vasculitis, or defects in the glomerular epithelial cell.AS is caused by a defect of type IV collagen, a component of the GBM. The cause in 80% of cases is an X-linked disease involving a gene defect of COL4A5 (which codes for the alpha 5 chain of type IV collagen). A common presentation for AS is a male child who has asymptomatic microscopic hematuria that may become overt hematuria in the presence of a respiratory infection. The renal lesion may progress to azotemia with nephrotic-range proteinuria in adolescence. End-stage renal disease has been reported in 50% to 90% of affected males by age 30 years, depending on the severity of the genetic defect. High-frequency sensorineural hearing loss occurs in approximately 50% of affected patients. A number of patients also have ophthalmologic findings, with anterior lenticonus, a defect of the lens bowing into the anterior chamber, being the most common. Due to the X-linked inheritance of this disorder in most patients, males often present earlier than females and have more severe disease. As such, males are more likely than females to develop chronic renal failure. As in this case, the evaluation of a male child who has persistent asymptomatic hematuria should include a dipstick urinalysis of the mother to screen for hematuria. Based on the genetics of this disorder, 50% of male children of female carriers are affected. At present, there is no specific treatment for AS. Nephrologists focus on blood pressure control and reduction of proteinuria, often with the use of angiotensin-converting enzyme inhibitors.Genetic defects of the alpha 3 or alpha 4 chain of type IV collagen result in an autosomal form of AS (autosomal recessive or dominant), which comprises the remaining 20% of cases of AS.Thin GBM disease has overlapping characteristics with AS in that it runs in families, is caused by a defect of the GBM, and results in persistent microscopic hematuria. Recently, thin GBM disease has been traced to a heterozygous state for the gene defect of alpha 3 or alpha 4 of type IV collagen, which explains why it has a much more favorable prognosis than AS. Question 94 Answer: A The findings of cola-colored urine, swelling, and hypertension described for the boy in the vignette suggest the diagnosis of acute glomerulonephritis. The "sore throat" 10 days earlier makes acute poststreptococcal glomerulonephritis (APSGN) the most likely diagnosis. The initial assessment of a child in whom ASPGN is suspected must include measurement of blood pressure and serum creatinine to assess disease severity. Both severe hypertension and renal failure can occur as part of a rapidly progressive glomerulonephritis. After initial assessment, the most important diagnostic test is measurement of complement component 3 (C3) to confirm the presence of hypocomplementemia, which occurs in more than 90% of cases. ASPGN is an immune complex-mediated glomerulonephritis that follows an infection by a nephritogenic strain of group A beta-hemolytic Streptococcus of the pharynx or skin. The interval between pharyngitis and the development of APSGN is approximately 1 to 2 weeks. In contrast, the latency period between a skin infection and ASPGN is 3 to 6 weeks. Most patients who have nephritis have a subclinical infection, which is estimated to occur four to five times more frequently than overt disease. APSGN in children is characterized by hematuria (100%), proteinuria (80%), edema (90%), hypertension (70%), and azotemia (33%). Thus, the urinalysis will not be normal. In addition, gross hematuria occurs in approximately 40% of children who have overt disease. As noted previously, the characteristic laboratory feature of ASPGN is hypocomplementemia, which typically features depressed C3 and normal C4 values. The differential diagnosis of hypocomplementemic glomerulonephritis consists of membranoproliferative glomerulonephritis (MPGN) in a child who has disease limited to the kidney and systemic lupus erythematosus in a child who has multisystem disease. Rarer causes of hypocomplementemic glomerulonephritis include subacute bacterial endocarditis, shunt nephritis (in patients who have ventriculoatrial shunts), and essential mixed cryoglobulinemia. Treatment of ASPGN is typically supportive and aims to reverse the sodium and fluid retention through the use of diuretics accompanied by restriction of sodium and fluid. Vasodilators also may be used for patients who have severe hypertension. Antibiotics can reduce the risk of transmission of the nephritogenic strain of streptococci to close contacts. The key follow-up test is a repeat measurement of C3, which usually normalizes within 8 weeks. Patients in whom depression of C3 persists after 12 weeks may require a renal biopsy to rule out MPGN. The prognosis of ASPGN is excellent. Gross hematuria and hypertension usually resolve within a few weeks and proteinuria within a few months. Microscopic hematuria may persist for 1 to 3 years. A normal urinalysis result is inconsistent with any form of glomerulonephritis, and would, therefore, be highly unlikely in a child who has hypertension and cola- colored urine. A positive urine culture would be unexpected in this clinical scenario. Patients who have hemorrhagic cystitis typically have bright red blood in the urine, often accompanied by clots. Other pertinent parts to the history that are absent in this scenario would be symptoms of dysuria, abdominal pain, frequency, urgency, and possibly fever. Small vessel vasculitides such as Wegener granulomatosis, microscopic polyangiitis, and Churg Strauss disease are less common causes of glomerulonephritis and, therefore, anti-neutrophil cytoplasmic antibody testing is unlikely to be revealing. Another, less likely diagnostic possibility for the child in the vignette is lupus nephritis. However, anti-nuclear antibody should be measured in the setting of acute nephritis to exclude this possibility. Question 110 Answer: E The symptoms of tingling described for the boy in the vignette may be associated with hypomagnesemia and hypokalemia. Cisplatin is a chemotherapeutic agent that can cause acute losses of magnesium and potassium and chronic losses in some patients that necessitate chronic oral replacement of these electrolytes. Chemotherapeutic agents used to treat pediatric malignancies are associated with a number of untoward complications, including nephrotoxicity. The two classes of drugs that most commonly cause renal toxicity are the platinum drugs (cisplatin and carboplatin) and ifosfamide. The platinum drugs (cisplatin more than carboplatin) cause injury to the late proximal tubule and collecting duct. More specifically, the proximal tubular damage can result in alterations of the brush border and tubular necrosis. The clinical manifestations of this damage are polyuria, electrolyte abnormalities, and azotemia. Inappropriate tubular losses of magnesium, sodium, and potassium are typical and result in the need for aggressive replacement. Prevention of cisplatin-associated nephrotoxicity has been aimed at optimizing hydration before, during, and after the infusion. Mannitol also may be used. Studies have shown that although many of the effects of cisplatin are temporary, altered renal function and magnesium wasting persist in many patients in long- term follow-up. Ifosfamide, which is used to treat many pediatric solid tumors, has been associated with acute and chronic nephrotoxicity. This agent can result in the Fanconi syndrome due to damage to the early portion of the proximal tubule. As a result, glycosuria, phosphaturia, amino aciduria, proteinuria, and altered glomerular filtration rate can be seen. The risks of ifosfamide nephrotoxicity appear to be related to the age of the patient, coexisting nephrotoxins, and nephron mass (with worse outcomes in patients who have prior unilateral nephrectomy). Serum potassium concentrations can be influenced by a number of factors, including dietary intake, intestinal absorption, and urinary excretion. Because potassium is primarily intracellular, in the setting of alkalosis, it shifts intracellularly, and the serum concentrations decrease. Like potassium, magnesium is primarily contained intracellularly. It is absorbed in the ileum, and its extracellular concentrations are regulated in the kidney.When hypomagnesemia and hypokalemia occur together, renal causes should be strongly considered. A metabolic alkalosis may cause the serum potassium to fall, but should have minimal effect on magnesium. Moreover, the patient described in the vignette is not believed to be at risk for an alkalosis. In the setting of normal renal function without ongoing losses, magnesium and potassium concentrations would be expected to be normal, even in the setting of a dietary deficient in these minerals. The patient has only intermittent vomiting and loose stools, making losses from the gastrointestinal tract unlikely. Question 126 Answer: C The child described in the vignette has failure to thrive; symptoms of polyuria and photophobia; signs of apparent mild dehydration; and laboratory findings that include hypokalemia, metabolic acidosis, and hypophosphatemia. Such electrolyte disturbances are characteristic of Fanconi syndrome, a proximal tubulopathy that results in urinary losses of sodium, potassium, bicarbonate, phosphate, amino acids, protein, and glucose. Although the differential diagnosis for the causes of Fanconi syndrome in the pediatric patient is extensive, the condition often is due to a metabolic disturbance. Causes of Fanconi syndrome include inherited diseases such as glycogen storage disease, hereditary fructose intolerance, tyrosinemia, cytochrome c oxidase deficiency, galactosemia, Lowe syndrome, Wilson disease, Dent disease, and cystinosis. Acquired causes include heavy metal poisoning, ifosfamide, cisplatin, gentamicin, and ingestion of outdated tetracycline. The most common cause of Fanconi syndrome in pediatrics is nephropathic cystinosis. Cystinosis is a lysosomal storage disorder that affects all cells in the body. Cystine normally is a product of protein degradation that is transported out of the lysosome. In cystinosis, cystine accumulates within lysosomes, resulting in cellular dysfunction. This autosomal recessive disorder has an estimated incidence of 1 in 100,000 to 200,000 live births, which translates into approximately 15 new cases diagnosed each year in the United States. The CTNS gene, which is located on chromosome 17p13, encodes for cystinosin, a transporter protein responsible for transporting cystine out of the lysosome. Polyuria, polydipsia, growth failure, rickets, and electrolyte abnormalities manifest in the second half of the first postnatal year in approximately 95% of children who have cystinosis. Cystine accumulation within the proximal tubular cells may result in impaired energy generation and a subsequent defect in solute reabsorption. Cystine accumulation within the cornea results in intense photophobia, as described for the child in the vignette. Patients who have cystinosis also may develop hypothyroidism. Cystinosis may be suspected when cystine crystals are visible within the cornea during slitlamp ophthalmologic examination. The diagnosis is confirmed by the finding of an elevated white blood cell cystine concentration. Treatment includes replacement of electrolyte losses and oral cysteamine therapy. Cysteamine is directed at the transport defect in cystinosis and has been shown to prolong renal survival from 10 years in untreated patients to 23 years when instituted prior to 3 years of age. The practitioner evaluating a child who is failing to thrive should consider electrolyte measurement and renal function tests when no obvious nutritional cause is present. Polyuria, polydipsia, and nocturnal fluid intake (the child awakens from sleep to drink fluid) are suggestive of diabetes insipidus, but specific electrolyte abnormalities can indicate the possibility of Fanconi syndrome. The patient in the vignette is exhibiting failure to thrive, but the electrolyte panel,but the electrolyte panel, which includes a normal chloride value and metabolic acidosis, is inconsistent with that of a patient who has cystic fibrosis (CF). Patients who have CF typically have excessive loss of chloride in their sweat that results in hypochloremia and metabolic alkalosis. Patients who have primary hyperparathyroidism have low phosphorus and slightly low bicarbonate values, but have hypercalcemia. This patient’s normal calcium concentration and hypokalemia are inconsistent with an abnormality of parathyroid hormone secretion. Urine ammonia measurement can be useful in patients who have distal renal tubular acidosis, which is associated with normal anion gap metabolic acidosis, but few of the other electrolyte abnormalities reported for this patient. Urine chloride measurement is useful for those who have Bartter syndrome and Gitelman syndrome, which could explain the hypokalemia and hypomagnesemia, but these conditions are associated with hypochloremic metabolic alkalosis, which is not present in the patient in the vignette. Question 150 Answer: E Hypertension is a major cause of morbidity and mortality in adults, and growing data suggest that it is becoming a greater clinical problem in the pediatric population, particularly adolescents. Although yet to be defined clearly, the lifelong risks for the child who has hypertension or a prehypertensive state are likely to be substantial. Blood pressure is affected by height, weight, sex, and race. A complete medical history, particularly family history and medications (including over-the-counter supplements), and a thorough physical examination are essential to early and accurate diagnosis of hypertension and assessment of its secondary causes, comorbidities, and potential complications. Measurement of the blood pressure is a salient component of the yearly health supervision visit for children beginning at 3 years of age. When the patient is calm and relaxed, blood pressure should be measured in the right arm with the patient seated and the arm resting at the level of the heart. The stethoscope should be placed about 2 cm superior to the cubital fossa, just over the brachial artery. It is extremely important to use the proper size cuff for each patient. The bladder of the cuff (not the cuff material) is the most important determinant of cuff size. The bladder width should cover 60% to 70% of the upper arm length. The cuff bladder length should cover 80% to 100% of the circumference of the arm to ensure complete compression of the brachial artery during cuff inflation. A cuff that is too small will result in a falsely elevated reading. A cuff that appears too large will not affect the measurement adversely. Most errors in blood pressure measurement occur in obese or highly muscularized patients when a cuff is used that is too small. Severe hypertension and hypertensive crisis should be managed aggressively. The latter typically results from the ingestion of drugs that cause hypertension, injury, or disease of the kidney or previously unrecognized, progressive hypertension. Symptoms of severe hypertension may include headache, changes in vision, epistaxis, seizure, pulmonary edema with congestive heart failure, and those that may arise from renal failure.The patient described in the vignette has a significantly elevated blood pressure that involves marked and reproducible systolic and diastolic hypertension. The best management plan is to monitor his blood pressure while the cause is ascertained and treatment begun, which involves admission to the hospital and initial treatment with an intravenous antihypertensive agent. The goal of such therapy is to reduce the blood pressure by 25% or less over the first 8 hours and gradually normalize it over the next 48 hours to avoid complications (eg, cerebrovascular accident).The choice of chronic antihypertensive therapy depends, in part, on the cause of the hypertension, but for immediate short-term management, vasodilators (eg, calcium channel blockers, hydralazine, nitroprusside) are useful. These agents reduce the afterload against which the left ventricle pumps, thereby reducing its work and oxygen consumption. Alternatively, short-acting beta blockers could be used in the acute setting. When using beta blockers, however, the clinician must bear in mind their potential complications, including exacerbation of underlying asthma. Of importance, pharmacologic management of severe hypertension and hypertensive crisis should use medications that can be titrated to effect readily and have a fast onset of action. Diuretics, particularly the thiazide class, often are used as first-line antihypertensive agents for those who have mild or moderate hypertension that can be controlled on an outpatient basis. These may be used in combination with other agents, including but not limited to angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, if adequate control is not obtained with a single agent. The significant hypertension reported for the boy in the vignette requires immediate action; repeating the blood pressure measurement in 1 to 2 weeks is not appropriate. Question 158 Answer: E The child who has asymptomatic, isolated microscopic hematuria is seen frequently in the ambulatory setting. Results of a urine dipstick test in patients who have hematuria are positive for blood, indicating the presence of hemoglobin or myoglobin. A microscopic evaluation that reveals more than 5 red blood cells/high-power field, as described for the girl in the vignette, confirms the presence of hematuria. Because isolated microscopic hematuria has been found in 4% of children on at least one of four tested samples, evaluation is not recommended unless hematuria is present on at least two of three urine samples. Accordingly, the girl in the vignette should undergo repeat urinalysis in 2 weeks. The prevalence of hematuria in two of three samples is 1% in females and 0.5% in males.Red blood cells in the urine may arise from the kidney (glomerular or nonglomerular), ureter, bladder, or urethra. Persistent hematuria demands evaluation. It is customary to evaluate renal function by measuring blood urea nitrogen and creatinine and to obtain a complete blood count and platelet measurement (looking for thrombocytopenia as a possible a possible cause) and an erythrocyte sedimentation rate (looking for an underlying inflammatory cause of hematuria). In addition, serologic tests, including complement components 3 and 4, antinuclear antibody, and anti-double-stranded DNA, are recommended to look for markers of immune complex-mediated glomerulonephritis, which can be seen with postinfectious nephritis, membranoproliferative glomerulonephritis, and lupus nephritis. Recommended urine studies consist of urinalysis with microscopy, urine protein and creatinine measurement, and urine culture. Measurement of a urine calcium-to-creatinine ratio is advocated by some but is not universally supported. Finally, abdominal computed tomography scan is not indicated in teh evaluation of the patient who has isolated hematuria. This test may be helpful in identifying renal tumors, but these neoplasms usually can be diagnosed by ultrasonography.The absence of symptoms in children who have isolated microscopic hematuria allows the practitioner to defer urgent evaluation because the likelihood of an underlying systemic disease or a disease limited to the urinary tract that warrants urgent attention is low. Similarly, patients who have microscopic hematuria unaccompanied by proteinuria are unlikely to have a significant disruption of the glomerular capillary barrier. On the other hand, if a child is asymptomatic but has hematuria and proteinuria, evaluation should proceed promptly, looking for an underlying renal parenchymal disorder such as glomerulonephritis. Cystoscopy rarely is indicated in pediatrics, and the decision to pursue this invasive evaluation should be made by a pediatric urologist. Question 173 Answer: E The differential diagnosis for an infant who has hydronephrosis in the first postnatal year includes ureteropelvic junction (UPJ) obstruction, ureterovesical junction (UVJ) obstruction, single-system ureterocele, vesicoureteral reflux (VUR), and posterior urethral valves (usually causes bilateral hydronephrosis). If hydronephrosis is found on renal/bladder ultrasonography, voiding cystourethrography (VCUG) is undertaken to rule out VUR and assess for a filling defect in the bladder caused by a ureterocele (Item C173A). Following VCUG, a technetium-99m mercaptoacetyltriglycerine (MAG-3) radioisotope scan with furosemide is performed to assess for UPJ obstruction. If UPJ obstruction is present, the radioisotope exhibits delayed washout. During the test, furosemide is infused and may precipitate an episode of renal colic, as reported for the infant in the vignette. If a UPJ obstruction is diagnosed, the practitioner should contact a pediatric nephrologist or urologist to help with further management. A duplex collecting system with a ureterocele is detected by VCUG that reveals a filling defect in the bladder and VUR (in approximately 50% of cases). On ultrasonography, a multicystic dysplastic kidney (MCDK) (Item C173B) exhibits multiple large cysts that do not communicate and a rim of dysplastic renal parenchyma. An MCDK occurs unilaterally and has no inherent function. Obstructive uropathy from posterior urethral valves is characterized by narrowing of the posterior urethra (Item C173C) and is associated with bilateral hydronephrosis in nearly all cases and VUR in approximately 50% of cases. Nephrolithiasis is defined acalculus within the renal parenchyma. Ultrasonography may reveal a calculus. Only if the calculus moves into the collecting system would hydronephrosis or renal colic following a diuretic renal scan occur. A calculus within the collecting system is known as urolithiasis. Question 188 Answer: B A palpable abdominal mass in the newborn usually is related to the kidney. The most common lesions responsible are multicystic dysplastic kidney (MCDK) and hydronephrosis due to ureteropelvic junction (UPJ) obstruction. Anomalies such as MCDK are detected either on in utero ultrasonography or postnatally as an abdominal mass. On ultrasonography, the lesion is associated with large renal cysts that are noncommunicating (Item C188A). An MCDK is a nonfunctioning nephron unit; a patient who has a unilateral MCDK and a normal contralateral kidney is considered to have a single kidney. The incidence of MCDK is estimated at 1 in 4,000 live births. An additional important aspect of MCDK is that vesicoureteral reflux (VUR) occurs in approximately 30% of cases into the functioning, contralateral kidney. Also, approximately 15% of contralateral kidneys may have a component of obstruction. The standard approach to an infant in whom a unilateral MCDK is diagnosed begins with the institution of prophylactic antibiotics (based on the 30% risk of VUR in the contralateral kidney). Voiding cystourethrography and a diuretic renal scan (DRS) should be obtained. The DRS generally demonstrates normal uptake by the "healthy" contralateral kidney and absence of uptake in the region of the nonfunctioning MCDK. If not diagnosed by in utero ultrasonography, hydronephrosis may present as an abdominal mass in the newborn period. The most common cause is UPJ obstruction. More rarely, it is caused by ureterovesical junction (UVJ) obstruction, single-system ureterocele, or VUR. The approach to a patient in whom hydronephrosis is suspected begins with renal/bladder ultrasonography to confirm the hydronephrosis and screen for other lesions while assessing the contralateral kidney. Prophylactic antibiotics are recommended, followed by voiding cystourethrography to look for VUR and a technetium- 99m mercaptoacetyltriglycerine (MAG-3) radioisotope scan with furosemide to screen for UPJ or UVJ obstruction. Less common causes of an abdominal mass in a newborn include gastrointestinal abnormalities (eg, bowel duplication), neuroblastoma, renal vein thrombosis, and Wilms tumor (rare in this age group). Question 203 Answer: E A child who has a febrile urinary tract infection (UTI) has a 30% to 50% likelihood of having underlying vesicoureteral reflux (VUR). VUR is the reflux of urine from the bladder into the ureter and possibly kidney across the ureterovesical junction (UVJ). It may be caused by anatomic abnormalities of the UVJ or bladder (eg neurogenic bladder) or bladder outlet dysfunction (eg posterior urethral valves). VUR is estimated to occur 10 times more frequently in Caucasians than in African-Americans. Males and females are nearly equally affected, and their prognosis is similar. There appears to be a strong familial association for VUR, with approximately 30% of siblings of an index case also having VUR when studied by voiding cystourethrography (VCUG). Despite this association, screening of asymptomatic siblings of affected children is controversial because VCUG is an invasive procedure and the benefit of identifying and treating (with prophylactic antibiotics) a child who is well and lacks symptoms is uncertain. At present, there is no consensus of opinion, although the trend is not to study asymptomatic older siblings who are toilet trained; some recommend that asymptomatic siblings younger than 1 year of age undergo VCUG. The American Academy of Pediatrics recommends performing ultrasonography and VCUG in all children after their first febrile UTI. The present standard of care for patients who have VUR is to receive prophylactic antibiotics until the reflux has resolved. Patients typically undergo a follow-up VCUG every 12 to 18 months; the time between VCUG studies is somewhat dependent on the age of the patient and the severity of reflux. An international classification system for VUR has grades ranging from mild (grade I) to severe (grade V). A nonsurgical approach is recommended for children who have grades I to III reflux; spontaneous resolution occurred in 80% of cases within 5 years of the diagnosis in one study. Grade IV reflux also often is managed nonsurgically. Grade V reflux traditionally has been managed surgically. A newer technique that involves endoscopic subureteral injection of dextranomer/hyaluronic acid may offer an alternative to conventional ureteral reimplantation surgery. Long-term data for this technique are not yet available. Question 209 Answer: C Constipation is defined by infrequent or difficult passage of large or hard fecal material. It occurs commonly in the pediatric population, and its association with urinary tract dysfunction has been well described. Constipation can cause detrusor instability, which can lead to urinary incontinence, large bladder capacity, and dyscoordinated voiding. Urinary retention is common, either from dyscoordinated voiding or from outflow tract obstruction caused by large rectal fecal masses. All of these types of urinary dysfunction can lead to recurrent urinary tract infections. One study of children who had urinary retention found that 13% had functional constipation as the cause of their retention. Another found that approximately 30% of chronically constipated children complained of urinary incontinence, and 11% had urinary tract infection. Treatment of the underlying constipation improved urinary incontinence and prevented recurrent urinary tract infections. The girl described in the vignette is otherwise healthy and growing well, and she has no anatomic urinary tract abnormalities. Accordingly, treatment of her underlying constipation is the next best step in the prevention of recurrent infections. Fecal disimpaction, stool softeners, and regular bowel evacuation using timed toilet sitting are the mainstays of treatment. An evaluation for immunodeficiency is not warranted at this time, but could be considered if her growth parameters were abnormal or if she had additional infections outside of the urinary tract. Renal scintigraphy is used to assess renal anatomy and function and may be warranted in a child who has recurrent urinary tract infections, but it is not helpful in preventing future infections. Anticholinergic therapy, such as oxybutynin, can be helpful if overactive or unstable bladder is suspected, but the girl in the vignette has no symptoms of these conditions. Referral to a pediatric nephrologist may be indicated if evidence of renal dysfunction is present, but treatment of underlying risk factors, such as constipation, should be initiated first. Question 211 Answer: A Hypertension is a major cause of morbidity and mortality in adults, and growing data suggest that it is becoming a greater clinical problem in the pediatric population, particularly adolescents. Although yet to be defined clearly, the lifelong risks for the child who has hypertension or a prehypertensive state are likely to be substantial. Blood pressure is affected by height, weight, sex, and race. A complete medical history, particularly family history and medications (including over-the-counter supplements), and a thorough physical examination are essential to early and accurate diagnosis of hypertension and assessment of secondary causes, comorbidities, and potential complications. Specific questions in the history should seek to identify clinical findings that might suggest an underlying systemic disorder, including the presence of gross hematuria, swelling or edema, shortness of breath, or rashes. The past medical history should focus on prior hospitalizations, previous trauma, and urinary tract infections. The family history should evaluate for hypertension, diabetes, obesity, stroke, and renal disease. In addition, the history should explore the possibility of medications or drugs (prescribed, illicit, or over-the-counter) that can be associated with hypertension. An example of the latter may be the use of pseudoephedrine as a nasal decongestant. Additionally, some families and adolescents use dietary supplements, vitamins, herbal remedies, and homeopathic preparations. Some of these "supplements" may be associated with sympathomimetic or hypertensive effects. The laboratory and diagnostic evaluation of the child who has hypertension should be guided by findings on the history and physical examination. For the pediatric patient who has confirmed hypertension, a screening panel of electrolytes, blood urea nitrogen, and creatinine as well as urinalysis and culture are indicated. Such blood tests are obtained to rule out renal disease. A urinary drug screen is indicated if the history or patient behavior suggests a possible contribution by illicit substances, drugs, or supplements that can be associated with hypertension. The child described in the vignette is overweight, but he has no historical or physical examination findings suggestive of the use of illicit substances, drugs, or supplements. Echocardiography also is not necessary at this stage of diagnosis because there is no evidence of congenital heart disease such as coarctation or end-organ involvement. Pediatric patients who have comorbid factors such as diabetes or systemic lupus erythematosus should undergo echocardiography as part of their hypertension evaluations. Radionuclide imaging of the kidneys involves exposure to ionizing radiation and typically is reserved for children of this age whose blood pressures are more than 5 mm Hg greater than the 99th percentile. Although renal vascular ultrasonography does not involve ionizing radiation, it also generally is reserved for young children whose blood pressures are beyond the 95th percentile and older children and adolescents whose blood pressures exceed the 99th percentile. Question 218 Answer: B Escherichia coli is the causative organism in 80% to 90% of first-time urinary tract infections (UTIs) in children. Other pathogens include Klebsiella pneumonia, Proteus sp, Enterococcus sp, and Staphyloccus saprophyticus. Pseudomonas also can be a pathogen in immunocompromised patients or those who have received repeated courses of antibiotics for recurrent infections. The clinician must assess the patient for a UTI based on signs, symptoms, and urinalysis findings. Organisms such as E coli, K pneumoniae, and Proteus sp can reduce dietary nitrate to nitrite, so a positive urine dipstick test for nitrite, as reported for the girl in the vignette, is virtually diagnostic of gram-negative bacteruria. If the test result is negative in an older child in whom a UTI is suspected, the infection may be caused by a gram- positive organism such as Enterococcus sp or S saprophyticus. Of note, the nitrite test is much less helpful in infants. Conversion of nitrate to nitrite may take up to 4 hours. Because infants and young children have small bladder volumes and urinate frequently, there may be insufficient time for nitrites to be formed and, therefore, the nitrite test may be negative even in the presence of a UTI caused by a gram- negative organism. Urine pH also may be useful in diagnosing UTIs. Urease-producing organisms (eg, Proteus mirabilis, some strains of S saprophyticus) degrade urea into ammonia, resulting in an elevated urine pH (8.0 to 8.5). The girl described in the vignette has symptoms of a lower UTI. Options for therapy include trimethoprim-sulfamethoxazole (if local resistance patterns indicate low levels of E coli resistance) or a third-generation cephalosporin (eg, cefixime, cefdinir). These antibiotics also may be used for outpatient management of acute pyelonephritis. For hospitalized patients, a third-generation cephalosporin such as ceftriaxone or cefotaxime provides adequate coverage. An alternative regimen is ampicillin plus gentamicin. Question 233 Answer: E The fever, chills, vomiting, abdominal pain, dysuria, and costovertebral angle tenderness described for the girl in the vignette suggest acute pyelonephritis. Laboratory evaluation demonstrates leukocytosis and abnormal urinalysis findings of hematuria, proteinuria, positive leukocyte esterase, positive nitrite, pyuria, and bacteriuria. The initial imaging technique in children who have urinary tract infections (UTIs) is renal/bladder ultrasonography to identify anatomic abnormalities, such as hydronephrosis, renal cysts, nephrolithiasis, urolithiasis, ureteral dilatation, duplex collecting system, bladder wall thickening, and ureteroceles. Following renal/bladder ultrasonography, a child who has a first febrile UTI should undergo voiding cystourethrography (VCUG) to screen for the presence of vesicoureteral reflux (VUR), which typically is present in approximately 30% of patients who experience their first UTI. There are two forms of cystography: fluoroscopic VCUG and radionuclide cystography (RNC). The fluoroscopic VCUG provides more detailed assessment of the reflux severity and reveals much more anatomic detail of the bladder and urethra. Therefore, males who have a first-time UTI must undergo fluoroscopic VCUG initially to rule out posterior urethral valves. Females for whom there are concerns of possible dysfunctional voiding also should undergo a fluoroscopic VCUG to assess bladder capacity and bladder emptying. Other patients and those previously found to have normal bladder and urethral anatomy by fluoroscopic VCUG may be evaluated by RNC, which is associated with reduced radiation exposure. Abdominal computed tomography has a limited role in evaluating patients who have acute pyelonephritis. It is most useful when the child is not improving despite appropriate antibiotic treatment and concern exists for a renal abscess. Cystoscopy (useful for stone removal or incisional treatment of a ureterocele). Mercaptoacetyltriglycine (MAG-3)-Tc99 nuclear medicine renal imaging with furosemide (which may detect ureteropelvic junction obstruction), and intravenous pyelography have no role in the evaluation of a child who has a history of acute pyelonephritis. Another nuclear medicine scan, dimercaptosuccinic acid (DMSA)-Tc99, can identify regions of hypoperfusion within the renal parenchyma that occur in acute pyelonephritis or as a result of chronic renal scarring. However, its use generally is limited to those patients in whom uncertainty about the diagnosis of acute pyelonephritis exists. Question 241 Answer: D Hypertension may be caused by medications, including over-the-counter preparations, dietary supplements, and illicit drugs. Essential, or primary, hypertension has no identifiable cause, but secondary hypertension results from an underlying condition, disorder, drug, or other stimulus. Among the agents that can cause hypertension are corticosteroids, estrogens such as those in contraceptive therapy, migraine medications, nasal decongestants, and cyclosporine. Over-the-counter preparations that can be associated with hypertension include the many medications used for relief of cough, cold, and runny nose. Substances of abuse that can cause hypertension include alcohol, amphetamines, cocaine, and Ecstasy (MDMA and its derivatives). The patient described in the vignette has tachycardia and hypertension, with both the systolic and diastolic pressures being higher than the 95th percentile. Other important findings in the history include a relative weight loss from the 50th percentile at age 14 to the 25th percentile (3.5 kg/7 lb) at age 15 years. It is essential to obtain more detailed information regarding the family history, past medical conditions, hospitalizations, and medication use. The patient confirms the use of over-the-counter cold remedies, some of which are known to be associated with hypertension as well as vitamins. She should be asked for further information about these substances. Because this is her first documented episode of hypertension, neither an evaluation for pheochromocytoma nor computed tomography scan of the abdomen is warranted. Without further information regarding her dietary habits, there is no indication that she has anorexia nervosa. Similarly, findings on the history are not suggestive of the muscularization or other physical changes that can be associated with anabolic steroid use. Question 248 Answer: D The boy described in the vignette has new-onset nephrotic syndrome (NS). The first important step is to establish the diagnosis based on the presence of severe proteinuria, hypoalbuminemia, and edema. Next, the practitioner must note the child?s blood pressure (BP) and assess renal function by measuring a serum creatinine because mild degrees of BP elevation and mild azotemia are consistent with NS, but marked elevations of BP or creatinine are not. In addition, approximately 20% of children presenting with new-onset NS have microscopic hematuria; gross hematuria should not be present. The next phase of the evaluation involves screening for secondary causes of NS. Typically, a serologic evaluation includes measurement of complement components (C3 and C4), antinuclear antibody, anti- double-stranded DNA, hepatitis B surface antigen and core antibody, hepatitis C antibody, and human immunodeficiency virus antibody. A complete blood count is obtained to look for hematologic abnormalities associated with NS, such as leukemia/lymphoma or sickle cell disease. A purified protein derivative test is placed to look for occult tuberculosis infection prior to starting treatment. If no secondary cause of the NS is identified by these tests, the treatment of choice is oral prednisone beginning at 60 mg/m2 per day in divided doses (maximum dose, 40 mg twice per day). The duration of daily therapy is 4 to 6 weeks, after which time the dose is reduced to 40 mg/m 2 (maximum daily dose, 60 mg) on alternate days for 4 to 6 weeks. Recent studies suggest that a longer course (6 weeks daily followed by 6 weeks alternate-day) results in a higher sustained remission rate than a shorter course (4 weeks daily followed by 4 weeks alternate-day). Although a low-sodium diet is recommended for children who have new-onset NS, it is adjunctive, not definitive therapy. Diuretics such as furosemide are not recommended in patients who have NS due to an increased risk of thrombosis. A protein-rich diet has no role in the treatment of NS because the hypoalbuminemia is due to glomerular losses, not malnutrition. Although allergies can cause periorbital swelling and may be treated with an antihistamine such as diphenydramine, patients typically exhibit other symptoms, such as rhinitis, sneezing, or conjunctival injection. If uncertainty exists as to the cause of periorbital swelling and there is concern about possible NS, performance of a urinalysis to detect proteinuria may be useful.
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