Urologic Stone Disease

Urologic Stone Disease Tintinalli Chapters 96-97 Randall Adolph Epidemiology • 3:1 M:F (~7% men/ 3% women) • 3rd-5th decade most common (70%) • Hereditary predisposition (RTA type 1, Hyperparathyroidism, cysteinuria, milk-alkali syndrome, sarcoidosis, Crohn's disease) • Climate (mountainous, desert, or tropical) • Time of year (warmest three months) • Lifestyle (sedentary) • Medications: protease inhibitors, carbonic anhydrase inhibitors, laxatives, triamterene Patient Characteristics • <16 year old comprise 7% of cases • 1:1 M:F • Causes: metabolic abnormalities 50%, urological abnormalities 20%, infection 15%, immobilization 5% • 1/3 have recurrence within 1 year • 50% within 5 years Pathophysiology • Formation requires three key elements 1. Supersaturation of urine with solutes 2. Relative lack of the inhibitors citrate & pyrophosphate 3. Stasis or lack of urine flow • Composition: 1. 75% calcium oxalate 2. 10% staghorn calculi (struvite): associated with urease-splitting bacteria, poor Ab. penetration and usually require surgery 3. Uric acid stones 10% Composition Continued • Calcium oxolate Hyperoxaluria occurs in the presence of small bowel disease-Crohn's disease, ulcerative colitis, and radiation enteritis. • Uric Acid10% of all stones – excessive excretion of uric acid in the urine – increases with uricosuric agents – Radiolucent!!! Obstruction leads to: • Rapid redistribution of renal blood flow, ↓ glomerular filtration rate  renal excretion shifts to unaffected kidney • Causes rapid decrease in ureteral peristaltic activity • Complete obstruction may lead to loss of renal function • Increased occurrence of irreversible damage after 1 to 2 weeks of obstruction • Partial obstruction lower likelihood of renal injury, may still result in irreversible damage. Critical size • 5 mm~ 90% < 5 mm and located in the lower ureter pass spontaneously • 15% pass if between 5 and 8 mm • 95% >8 mm become impacted generally requiring lithotripsy or surgical removal • 75% of stones are located in the distal third of the ureter Area of impaction • Renal calyx • UPJ, where ureter passes over pelvic brim and iliac vessels • UVJ: smallest diameter of the urinary tract • In FM the posterior pelvis: ureter is crossed anteriorly by the pelvic blood vessels and broad ligament Places for obstruction Causes of pain • Colicky, severe flank pain: hyperperistalsis of smooth muscle of the calyces, pelvis, and ureter • Dull ache: attributed to acute obstruction and renal capsular tension Clinically • • • • Usually asymptomatic until obstructs acute onset severe pain, typically at rest little if any POP Typically flank, abdomen with referral to ipsilateral labia or testicle • May be writhing in pain, reluctant to lie still • Episodic as passes, pain free until obstructs more distally Urinary pH • pH> 7.6 suspicious for urea-splitting organisms because the kidney will not, under normal conditions, produce urine in this alkaline range. • pH < 5 often associated with the formation of uric acid calculi. LABORATORY • UA hematuria supports diagnosis, absent in 15% ;crystals seen w/wo stones • Dipstick detects heme, myoglobin and porphyrins, need micro (see RBCs) • Urine C&S, • BUN & Creatinine especially if imaging with RCM, higher rates of complications in DM >1.5, CRF >2.5 Imaging • performed with a first episode of renal colic. • Other indications: – Diagnosis is unclear – Those in whom a proximal UTI, in addition to a calculus, is suspected. • A KUB is the standard, initial radiograph done before injecting contrast media during IVP. Imaging • Helical CT preferred modality • US if pregnant • Others IV urography, Radionuclide renal scan, plain abd. Film • Shows stone, location, IDs complications • Unilateral ureteral dilatation and perinephritic stranding together: PPV 96% • Both absent NPV 93-97% Noncontrast CT • Advantages: fast, avoids RCM, • Disadvantages: specificity/sensitivity low for other pathologies (AAA, appendicitis) • Does not evaluate renal function or degree of obstruction • If negative may need RCM to look for other cause of pain IV Urography • Indicators of obstructing stone: – 1st and most reliable indicator of obstruction is a delayed nephrogram in the 5-minute film – Visualization of the entire ureter is suggestive of obstruction – Ureteral contrast column cutoff, prolonged nephrogram, renal enlargement, dilatation of the collecting system, contrast extravastation Helical CT • • • • • Advantages: provides info on function Disadvantages: uses RCM (allergy,nephrotoxic) Nephrotoxicity: 9% in pts. with RI or DM BUN, Creatinine before RCM Metformin & RCM  severe Lactic acidosis, nephrotoxicity • False negative if stone small, radiolucent, partially obstructing, or passes into bladder before contrast passed by kidneys US • • • • • During pregnancy, children May misses stones < 5mm Less sensitive in middle ureter Overall low sensitivity/specificity for stones 98% sensitive for hydronephrosis, however 22% of cases not associated with obstruction US • Advantages: – noninvasive, no dyes or radiation, no known side effects – Superior to IVU for UVJ stones • Disadvantages: – excretion function not evaluated operator and equipment dependant – obesity may hinder ability to perform Plain Films • 90% stones radiopaque (Ca > Struvite > Cystine) • Uric acid and stones associated with medications radiolucent • Overall poor Sensitivity & Specificity • Greatest utility is excluding other pathologies Stone gone wild • infection occasionally occurs in the presence of an obstructive stone. • A history of fever and chills strongly suggests superimposed infection and is a urologic emergency. It is imperative to do an IVP or an ultrasound study in these cases • Sterile pyuria strongly suggests renal tuberculosis; confirmation acid-fast bacilli Differential Diagnosis • Aortic dissection , AAA • Appendicitis: usually don’t see rebound, guarding, distention with stone • Infectious: fever with CVA, consider pyelonephritis • Papillary necrosis: DM, SCD, NSAID abuse; see Hematuria and pyuria • Vascular:Renal vein thrombosis, Mesenteric ischemia • Gynecological vascular etiology • If suspected, a contrast CT or angiogram done. • Relatively rare: m/c renal artery embolism, most often of cardiac origin (atrial fibrillation, subacute bacterial endocarditis, mural thrombus) • IVP should demonstrate decreased or absent excretion of contrast material. Immediate angiogram indicated early diagnosis allows possible salvage of the ischemic kidney Predisposing factors for renal vein thrombosis include the nephrotic syndrome, malignancies, and pregnancy TREATMENT • Pain control: Opiods and nsaids • NSAIDs: analgesic, decrease ureterospasm and renal capsular pressure by diminishing GFR in the obstructed kidney. • Obstruction with Infection: Urology emergency • Consult if: RI, Severe underlying disease, extravasation or complete obstruction, Multiple ED visits, large stone, sloughed renal papillae Management • Average time to pass stone varies (7-20 days) • Long acting CCB (Nifedipine) and steroids may enhance passage • F/U Urology in 7 days • Stone saved/submitted to urologist for analysis. • Dispo: return immediately if intractable, severe pain, persistent nausea and vomiting, fever and chills Indications for Admission • • • • • • • • • • • Obstruction with infection Persistent pain Persistent nausea and vomiting Urinary extravasation Hypercalcemic crisis High-grade obstruction Solitary kidney Intrinsic renal disease Size of obstructing stone Duration of symptoms Social situation Relative Indications for Admission Admit • severely dehydrated • unrelenting pain or vomiting • underlying infection with hydronephrosis Bladder stones • different from renal stones • almost exclusively elderly men • most often complication of other urologic disease (Proteus). • The other common indwelling catheter • May complain of sudden interruption of the urinary stream. This strongly suggests a vesical stone that intermittently obstructs the bladder outlet Hematuria and Hematospermia • Tintinalli Chapter 97 Hematuria • Definition: – >5 RBCs/hpf warrants an attempt at definitive diagnosis • Timing: – Initial suggests urethral disease – B/n voiding and only staining undergarments, with clear urine distal urethral or meatus – Total disease of kidneys, ureters, or bladder – Terminal bladder neck or prostatic urethra • Amount – Gross hematuria lower tract cause while microscopic tends to be kidney disease • Color: – Brown/Smokey colored with casts and proteinuria suggests glomerular – Red clotted blood indicates source below kidney HEMATURIA • a harbinger of serious urologic disease • Gross hematuria  5X more likely to have lifethreatening conditions when compared to those with microhematuria. • Lower and middle urinary tract ~60% • Urologic malignancies 2.2% to 12.5% with microscopic hematuria, up to 20% if > 50 years with gross hematuria. • Gross hematuria (>3 red blood cells/hpf on two of three urinalyses found a potentially life-threatening lesion in 9.1% of these patients. Hematuria • Young Pts. most often urolithiasis or UTI • Consider glomerulonephritis, goodpasture, HSP, Wilms Tumor, SCD/trait • PSGN 7-14 days following pharyngitis, Abs do not prevent this • IgA nephropathy following viral URI • Elderly: infection, Nephroolithiasis, bladder, prostate, renal CA Other sources of bleeding • infection of the bladder (hemorrhagic cystitis) • varices of the bladder • Diverticula • bladder stones • postradiation changes • Anticoagulation at currently recommended levels does not predispose patients to hematuria Risk factors for Uroepithelial CA • • • • • • • Age >40 Excessive analgesic use Smoking Exposure to dyes, benzenes, aromatic amines Pelvic irradiation Cyclophosphamide Hematuria in patients on blood thinners, have underlying disease 80% of the time glomerular and nonglomerular • glomerular origin: frequently associated with dysmorphic erythrocytes, RBC casts, and significant proteinuria (2+ to 3+) • IgA nephropathy (Berger's disease) m/c, cause • nonglomerular hematuria: uniformly round erythrocytes and absence of erythrocyte casts and proteinuria. glomerular disease • Typically young males have hematuria, erythematous skin rash, and fevers suggesting immunoglobulin nephropathy, or Berger's disease • Family history of deafness, renal disease, and hematuria is linked to Alport nephritis. • A rash, arthritis, and hematuria are seen with systemic lupus erythematosus. • Hematuria, hemoptysis, and microscopic anemia are common presentations of Goodpasture's syndrome. • A preceding upper respiratory infection, pharyngitis, skin infection, or rash with associated hematuria suggests poststreptococcal glomerulonephritis. nonglomerular disease • A family history of bleeding disorders or renal cystic disease suggest hemophilia and polycystic kidney disease, respectively. • Suspect papillary necrosis in diabetics, sickle cell patients, and analgesic abusers (Classic urolithiasis, sudden flank pain and hematuria) Diagnosing • • • • • Clarify symptoms and source: traumatic/atraumatic Gross/micro Initial/total/terminal Associated symptoms: flank pain, menstruation, dysuria, etc. • Travel (schistosomiasis) • Abnormal RBC morphology, casts, protein suggest glomerular source • Strenuous exercise frequently cause, but deserves investigation even if spontaneously resolves Exercise-Induced • Exercise-induced hematuria that does not resolve after 48 hours commonly results from punctate hemorrhagic lesions suggesting bladder cancer • Diagnosed by cystoscopy dipstick • positive only if there has been lysis of RBCs or with myoglobinuria. • [Hemoglobin] greater than 0.003 mg/L (10,000 red blood cells/mm3 or 1 to 2 RBCs/hpf) • Current recommendations: urinalysis and cytology for 3 consecutive years if resolution of hematuria or persistent asymptomatic microhematuria • ross hematuria should be reevaluated in all instances Renal Imaging • IVP clearly delineates most renal tumors, obstruction, or stones and their precise location – Disadvantage: RCM, does not assess aorta, retroperitenium and pelvis • Helical CT fast highly sensitive and specific for stone, RCM used for other pathologies • Renal US to screen for AAA, Hydro, obstruction. Study of choice in Pregnant and children – Disadvantages: rarely identifies small stones, no idea of functioning, Treatment • Abs. for infection • Pain meds. & hydration for nephrolithiasis • D/C only if asymptomatic, tolerating PO, Abs. & analgesics & no sig. comorbidities • <40 to PCP for repeat UA 1-2 weeks, if persists or >40 and risk for CA, Urology for cystoscope • Asymptomatic microscopic hematuria associated with a 2 fold increase of future RF • Proteinuria: a sign of prognostically significant glomerular disease & needs further workup Complications • Gross hematuria may lead to intravesical clot and subsequent outflow obstruction • New glomerulonephritis: at risk for Pulmonary edema, volume overload, azotemia or HTN emergency need admission • Pregnant: May be preeclampsia, pyelonephritis, obstructing stone call OB and possibly admit Hematospermia • Trauma, injury (tumor with erosion), inflammation, infection of ejaculatory system • M/C iatrogenic from instrumentation, radiation. • >40 prostate CA, BPH considerations • <40 prostatitis, seminal vesiculitis, urethritis, STD, epididymo-orchitis, calculi, TB • UA warranted • Usually benign, but urology referral indicated Questions? Question 1 • What season is associated with an increased incidence of stones? a) b) c) d) Winter Spring Summer Fall Answer C Question 2 • True or false: Hematuria seen in a patient on therapeutic levels of blood thinners is usually microscopic and benign? False: underlying pathology 80% of time Question 3 • In the ED what is a value fror defining hematuria? a) b) c) d) Any RBCs/hpf 2 RBCs/hpf 4 RBCs/hpf 5 RBCs/hpf Answer: D Question 4 • The most common cause of stone formation is? a) b) c) d) metabolic abnormalities urological abnormalities infection Immobilization a) Answer: A 50% Question 5 • What is the most common composition of renal stones? a) b) c) d) Uric acid stones struvite calcium oxalate Magnesium Answer: C