Name
NEPHROPATHY, URATE
DESCRIPTION
DETAIL
CAUSES . Primary . Congenital gout, hypertension and hyperuricemia (autosomal dominant) . Congenital HGPRT defi ciency (X-linked recessive) . Congenital PRPP overactivity (X-linked recessive) . Congenital glycogen storage disease, type I . Secondary . Lead intoxication . Diuretics . Cytotoxic chemotherapy in leukemia or lymphoma . Heat stress and exercise . Diabetic ketoacidosis . Starvation ketosis . Chronic myeloproliferative disease . Psoriasis -------------------------------------------------------------------------- DIFFERENTIAL DIAGNOSIS Other causes of acute renal failure, other causes of nephrolithiasis, other causes of chronic renal failure LABORATORY . Gout and hyperuricemia . Hyperuricemia . Hyperuricosuria in 10-20% . Decreased urinary ammonia production . Hyperuricemic acute renal failure . Serum uric acid greater than 15-20 mg/dL (0.88-1.18 mmol/L) . Rising BUN and creatinine . Urinary uric acid to creatinine ratio > 1 . Uric acid crystals in urine . Uric acid nephrolithiasis . Uric acid crystals in urine . Urinary uric acid greater than 600-700 mg (3.54-4.13 mmol) per 24 hours (hyperuricosuria) on purine-free diet . Hyperuricemia . Microhematuria . Pyuria . Positive urine culture . Stone composition uric acid or mixed uric acid and calcium oxalate or calcium phosphate . Hyperuricemia of chronic renal failure . Acute exacerbation of hyperuricemia with serum uric acid greater than 10 mg/dL (0.59 mmol/L) . Acute on chronic BUN and creatinine elevations SPECIAL TESTS Stone analysis IMAGING β’ IVP β’ Renal ultrasound DIAGNOSTIC PROCEDURES β’ Cystoscopy and retrograde pyelography β’ Renal biopsy
TYPENOTES
RISK FACTORS: Sudden increase in uric acid load, Dehydration, Urine pH less than 5, Hypertension, Diabetes mellitus, Renal insufficiency, Renal vascular diseaseGENERAL MEASURES . Hydration to increase urine output . Normalize serum uric acid . Normalize renal uric acid excretion . Decrease uric acid production . Maintain urine pH greater than 6 . Antibiotic treatment of urinary tract infection . Hyperuricemic acute renal failure: . IV hydration . Hemodialysis SURGICAL MEASURES Uric acid nephrolithiasis: Cystoscopic or surgical stone removal for persistent ureteral obstruction ACTIVITY Limited during attacks of acute gouty arthritis DIET . Purine restriction . Protein restriction . For nephrolithiasis, fluid intake adequate to produce urine output at least 2 L per day unless urine output is limited by acute or chronic renal failure . In acute renal failure restrict sodium for hypertension and potassium for hyperkalemia DRUG(S) OF CHOICE . Gout and hyperuricemia . Uricosuric agent - probenecid (Benemid) starting with 250 mg bid and doubling 7-10 day intervals up to 500-1000 mg bid (maximum 3 gm/day) . Xanthine oxidase inhibitor preferred for hyperuricosuria - allopurinol (Zyloprim) 200-300 mg/day. . Treatment of symptomatic or asymptomatic hyperuricemia with uric acid-lowering drugs has no apparent favorable or adverse effect with respect to development of renal insufficiency . Hyperuricemic acute renal failure . Prevent by pretreating with allopurinol and hydrating patient prior to administration of chemotherapeutic agents for leukemia or lymphoma . Loop diuretic . IV alkalinizing solution . Uric acid nephrolithiasis . Allopurinol 200-300 mg/day . Alkali to maintain urine pH 6.0-6.5 - sodium bicarbonate or potassium citrate-citric acid 0.5-1.5 mEq/kg in 5 or 6 divided doses . Hyperuricemia of chronic renal failure . Allopurinol in patients with prior history of gout ALTERNATIVE DRUGS Sulfinpyrazone (Anturane) PATIENT MONITORING . Serum uric acid, urinary uric acid excretion, BUN and/or serum creatinine at least twice a year . Blood pressure screening at least once a year PREVENTION/AVOIDANCE . Appropriate pretreatment prior to chemotherapy of leukemia or lymphoma . Avoid factors that can cause abrupt or persistent increases of serum uric acid or urinary uric acid excretion . Prompt treatment of urinary obstruction or infection . Control blood pressure in hypertensives POSSIBLE COMPLICATIONS . Gout and hyperuricemia . No apparent renal complications . Hyperuricemic acute renal failure . Irreversible renal failure (end-stage renal disease) . Residual renal insufficiency . Persistent renal tubular functional defects . Uric acid nephrolithiasis . Urinary obstruction . Urinary infection . Renal insufficiency . Hyperuricemia of chronic renal failure . Progression to end-stage renal failure EXPECTED COURSE/PROGNOSIS . With effective drug therapy and general management prognosis is excellent in patients with gout, hyperuricemia, or nephrolithiasis . Development or progression of renal insufficiency should not occur unless due to underlying renal disease or associated medical conditions with adverse renal effects
RELATED DISEASE
Not Available Disease
DISEASE
INVESTIGATION
BLOOD UREA, SERUM CREATININE, SERUM URIC ACID, URINE ROUTINE, ULTRA SOUND K.U.B., BUN, COMPLETE BLOOD COUNT