Urinary System Disorders

Urinary System Disorders Chapter 21 Pgs 420-444 Overview • Incontinence and Retention • Diagnostic Tests – Urinalysis – Blood tests – Other tests • Urinary Tract Obstructions – Urolithiasis – Tumors • Renal Failure – Acute – Chronic • Diuretic Drugs • Dialysis • Disorders of the Urinary System – Urinary Tract Infections – Inflammatory Disorders • Glomerulonephritis Incontinence and Retention • Loss of voluntary control of bladder • Stress incontinence – Increase in intra-abdominal pressure • Forces urine through sphincter – Laughing – Coughing – Females weakened • Inability to empty bladder • May accomp overflow incontinence • Spinal cord injury • Inability to control managed by pads, briefs • Catheter – Tube inserted in urethra – Drains urine from bladder to collecting bag – Common source of UTI • Spinal cord injuries, brain damage Catheter Diagnostic Tests—Urinalysis • Constituents, characteristics of urine vary w/ dietary intake, drugs, care of specimen • Normally clear, straw-colored; pH 4.5-8.0 • Appearance – Cloudy • Presence of lg amts protein, blood cells, bacteria, pus – Dark color • Hematuria (blood), excessive bilirubin, high concentration of urine – Unpleasant, unusual odor • infection Diagnostic Tests—Urinalysis • Abnormal constituents (high in numbers) – Blood (hematuria) • Small, microscopic amts – Infection, inflammation, tumors of UT • Lg # RBC – Increased glomerular permeability or hemorrhage in tract – Protein (Proteinuria) • Leakage of albumin into filtrate – Inflammation, increased glomerular permeability – Bacteria (Bacteriuria) and Pus (Pyuria) • Indicates UTI – Urinary casts • Microscopic mold of tubules – Consists of one or more cells, bacteria, protein • Inflammation of tubules – Specific gravity • Ability of tubules to concentrate urine • Low is related to renal failure RBC Cast Diagnostic Tests—Blood Tests • High serum urea and creatinine – Indicate failure to excrete N wastes • Due to low GFR • • • • • Metabolic acidosis – Indicates low GFR, failure of tubules to control acid/base balance Anemia – Indicates low erythropoietin secretion and/or bone marrow depression • Due to accumulating wastes Electrolytes Antibody level – Antistreptolysin O (ASO) or antistreptokinase (ASK) Renin levels – Indicate cause of hypertension Diagnostic Tests—Other Tests • • • Culture and sensitivity tests – Urine specimens • ID organism and select drug treatment Clearance tests – Creatinine, insulin clearance – Used to asses GFR Radiologic tests – – – – – Intravenous pyelography (IVP) Angiography Ultrasound CT, MRI Used to visualize structures and abnormalities • Cytoscopy – Visualize lower UT – Can be used to perform biopsy or remove kidney stones • Biopsy – Acquire tissue specimen for microscopic analysis IVP (Intravenous Pyelography) Angiography, Ultrasound CT CT, MRI Diuretic Drugs • Removes excess Na ion and water from body – Increase excretion of water thru kidneys and urinary vol • Take in morning • Prescribed for many disorders – Renal disease, hypertension, edema, CHF, pulmonary edema • Most commonly used drug group inhibits NaCl reabsorption • Major side effect is excess loss of electrolytes – Many cause excessive loss of potassium – Cause muscle weakness or cardiac arrhythmias Dialysis • Provides ―artificial kidney‖ – Sustains life after kidney fails • Acute renal failure or end-stage renal failure (those waiting for a transplant) • 2 forms – Hemodialysis – Peritoneal dialysis Hemodialysis • Hospital, dialysis center • Pt’s blood moves from implanted shunt in arm artery  tube  machine  exchange of wastes, fluids, electrolytes – Semipermeable membrane separates pts blood from dialysis fluid • Constituents move between the 2 compartments – Ex: wastes in blood  dialysate bicarbonate in dialysate  blood Blood cells, proteins remain in blood Movement by ultrafiltration, diffusion, osmosis  Blood to pt vein Hemodialysis • Heparin (anticoagulant) • Required 3Xs/week for 3-4 hrs • Potential complications – Shunt becomes infected – Blood clot forms – Blood vessels become damaged • Must move to new site – Increased risk of hepatitis, HIV Peritoneal Dialysis • • Administered in unit or at home At night or continuously – CAPD (continuous ambulatory peritoneal dialysis) • • • Peritoneal membrane serves as semipermeable membrane Catheter w/ entry and exit points implanted Dialyzing fluid instilled in catheter into cavity – Remains there – Allows exchange of wastes and electrolytes to occur – Dialysate drained from by gravity from cavity into container • • • Requires more time than hemo b/c continuous exchange, prevents sudden changes in fluid and electrolyte levels Complications – Infection in peritoneal cavity Peritoneal Dialysis Disorders of the Urinary System: Urinary Tract Infections (UTI) • Very common • Urine is excellent medium for microorganismal growth – Escherichia coli • Most are ascending – Perineal cavity  mucosa  bladder  ureters  kidneys UTI—Etiology • Females more anatomically vulnerable – Short urethra – Proximity to anus – Frequent irritation to tissues • Tampons, bubble bath, sexual activity • Older males with prostatic hypertrophy and retention of urine prone to UTI UTI—Etiology • • • • • Incontinence Bladder retention of urine Obstruction of urine flow Congenital abnormality Pregnancy, scar tissue, kidney stones, vesicourethral reflex – Urine does not flow freely • Decreased host resistance (immunosuppression) • Impaired blood supply to bladder (aging) • Diabetes mellitus UTI: Cystitis—Pathophysiology • Bladder wall and urethra inflamed, red, swollen – Decreased bladder capacity UTI: Cystitis—Signs and Symptoms • Pain in lower abdomen • Dysuria, frequency, urgency – Inflammation of bladder wall irritated by urine • Systemic signs of infection • Cloudy urine with unusual odor • Urinalysis indicates bacteria (+100,000/mL), pyuria, microscopic hematuria UTI: Pyelonephritis— Pathophysiology • 1 or both kidneys involved • Infection from ureter  renal pelvis  medullary tissue (tubules and interstitial) • Purulent exudate fills kidney pelvis and calyces • Abscess and necrosis seen in medulla – May extend thru cortex to capsule – Severe may compress renal artery and vein and obstruct urine flow to ureter • Bilateral obstruction results in acute renal failure • Recurrent chronic infection – Can lead to fibrous tissue over calyx • Loss of tubule function UTI: Pyelonephritis—Signs and Symptoms • Signs of cystitis • Pain – Dull aching in lower back – Results from renal capsule stretching • Urinalysis – Similar to cystitis – Except urinary cast • Leukocytes or renal epithelial cells present – Involvement of renal tubules UTI—Treatment • Antibiotics (Bactrim) • Increase fluid intake – Especially cranberry juice • Tannin decreases ability of E. coli to adhere to bladder mucosa • Infection reoccurs unless predisposing factors removed Disorders of the Urinary System: Inflammatory Disorders • Glomerulonephritis – Many forms • Acute Poststreptococcal Glomerulonephritis (APSGN) – Follows streptococcal infection » Originates as upper resp infection, middle ear infection, strep throat – Primarily affects kids 3-7 (especially boys) – develops 2 weeks after previous infection • Antistreptococcal antibodies create antigen-antibody complex – Type III hypersensitivity rxn – Lodge in glomerular capillaries • Cause inflammation in both kidneys – Increase cap perm and cell proliferation » Leakage of proteins and erythrocytes into filtrate Inflammatory Diseases: Glomerulonephritis— Pathophysiology • Severe inflammation – Congestion and proliferation interfere w/ filtration in kidney • Decrease GFR and retention of fluid and wastes – If blood flow impaired, acute renal failure • Low blood flow  increase renin  increase bp and edema – Scar tissue on kidney Glomerulonephritis—Signs and Symptoms • Back pain – Stretching renal capsule • Dark, cloudy urine • Oliguria • Facial edema, then generalized – Low osmotic pressure of blood – Salt, water retention • Generalized signs of inflammation • Increased bp Glomerulonephritis—Diagnostic Tests • Blood tests – High serum urea and creatinine and decreasing GFR – Streptococcal antibodies, ASO, ASK – Metabolic acidosis • Low serum bicarbonate, low pH • Urinalysis – Confirms presence of proteinuria, erythrocyte casts Glomerulonephritis—Treatment • • • • Sodium restriction Glucocorticoids Antibiotics Recovery w/ minimal damage – Imp to prevent further exposure to streptococcal infection and recurrent inflam – Adults more difficult • Acute renal failure in 2% • Chronic glomerulonephritis in 10% – Gradually destroys kidneys • Postrecovery testing should be done Urinary Tract Obstructions: Urolithiasis • Also called: – Calculi – Kidney stones • Frequently reoccur if not treated Calculi—Pathophysiology • Can develop anywhere in UT; lg or small • Once any solid material or debris forms • Tend to form when: – excessive amts of relatively insoluble salts are in filtrate – Insufficient fluid intake creates highly concentrated filtrate • 75% composed of calcium salts – Remainder: uric acid, struvite, oxalate • Usually cause manifestations only when obstruct flow of urine – Infection if stasis of urine Kidney Stones—Pathophysiology: Types of Stones • Calcium stones – Form when calcium levels high in urine • Hypercalcemia • Mixed inorganic salts – Infection • Debris from infection begin deposition of crystals – Urine pH alkaline • Uric acid stones – Develop w/ hyperuricemia • Due to gout, cancer chemo • Calcium oxalate – Certain vegetarian diets – High levels of oxalate in urine Kidney Stones Calculi—Signs and Symptoms • Stones in kidney/bladder frequently asymptomatic • Obstruction of ureter causes attack – ―renal colic‖ • Consists of intense spasms in back and groin • Pain caused by vigorous contractions of ureter – Effort to pass the stone Calculi—Treatment • Small stones eventually passed out • Larger stones – Extracorporeal shock-wave lithotripsy (ESWL) • Decreases need for invasive surgery – Some drugs can partially dissolve • Need to prevent recurrences ESWL Urinary Tract Obstructions: Tumors—Renal Cell Carcinoma • Primary, silent tumor • Arises from tubule epithelium • Asymptomatic in early stage – Often metastize to liver, lungs, bones, CNS at time of diagnosis • Common after 50 – More freq in males and smokers • Initial sign is painless hematuria • Other manifestations – Dull aching flank pain, palpable mass, anemia • Treatment is kidney removal – 5 yr survival rate 50% Renal Failure: Acute Renal Failure—Pathophysiology • • • • • May fail suddenly for different reasons Failure reversible if primary problem successfully treated Dialysis required Develops rapidly Either: – Directly decreases blood flow to kidney – Inflammation and necrosis of tubules cause obstruction and back pressure • Greatly decreases GFR and oliguria • Blood tests show high N (kidneys not removing wastes) • If cause not promptly treated, chronic Acute Renal Failure—Etiology • Acute bilateral kidney disease – Glomerulonephritis • Low GFR • Severe prolonged circulatory shock or heart failure – Results in tissue necrosis – Burns: Hb accum in tubules = obstruction • Nephrotoxins – Drugs, chemicals, toxins • Aspirin, NSAIDs, penicillin – Cause tubule necrosis and obstruction of blood flow • Mechanical obstruction – Calculi, blood clots, tumors – Block urine from leaving kidney Acute Renal Failure—Treatment • Important to reverse primary problem quickly • Dialysis • Recovery evidenced by increased urine output – May take couple months before renal tubules fully recover Chronic Renal Failure— Pathophysiology • Gradual, irreversible destruction of kidney nephrons • May result from: – Chronic kidney disease • Bilateral pyelonephritis – Systemic disorders • Hypertension • Diabetes – Long term exposure to nephrotoxins • Asymptomatic until well advanced – Due to reserve function of nephrons – Can’t be stopped once in advanced • Scar tissue and loss of functional organization – Further degenerative changes Chronic Renal Failure— Pathophysiology: Stages • Decreased reserve – 60% nephron loss – Low GFR, high creatinine levels • Both still in normal range – Normal urea levels – No apparent clinical signs – Remaining nephrons adapt • Increase capacity for filtration Stages • Renal Insufficiency – – – – – 75% nephron loss Changes in blood chemistry and manifestations GFR decrease to 20% of normal Significant retention of N wastes in blood Decrease tubule function • Failure to concentrate urine and control secretion for exchange of acids and electrolytes – Excretion of lg vol of dilute urine – High bp – Cardiovascular system compensates Stages • Uremia (End-stage renal failure) – +90% nephron loss – negligible GFR – Fluid, electrolytes, wastes retained in body • All systems affected – Oliguria or anuria – Regular dialysis or transplant needed to sustain life Chronic Renal Failure—Signs and Symptoms • Early signs – Increase urine output (polyuria) – General signs – Increase wastes and altered blood chemistry • Bone marrow depression, impaired cell function – Increase bp • Uremic signs – – – – – – – Oliguria Dry, hyperpigmented skin Peripheral neuropathy (abnorm sensations in lower limbs) Males impotence, decrease libido; females irreg menstrual cycle Encephalopathy (lethargy, memory lapses, seizures, tremors) CHF, arrhythmias Failure of kidneys to activate vitamin D • Leads to hypocalcemia, osteodystrophy, osteoporosis, tetany – Uremic frost on skin, urine-like breath – Systemic infection • pneumonia Chronic Renal Failure—Diagnostic Tests • Metabolic acidosis becomes decompensated – Serum pH below 7.35 – Low GFR – Tubule function lost • Azotemia – Presence of N wastes in blood • Severe anemia • Varying electrolyte levels – Depends on amt water retained Chronic Renal Failure • Affects all body systems • Difficult to maintain control of blood chemistry and body fluid levels • Drugs to treat: – Hypertension, arrhythmias, heart failure – Dosages adjusted b/c decreased ability to excrete them • Subject to many complications – Affect uremia – Infection increases wastes in body; compromises all body systems