Type of renal injury:
(1) crystal deposits within distal tubules and collecting duct
(2) lithiasis
(3) tubulointerstitial nephropathy
Risk factors for crystal deposition and lithiasis:
(1) volume depletion with concentrated urine
(2) urine pH > 3.5
(3) pre-existing renal disease
(4) hepatitis C viral infection
(5) hemophilia
Clinical findings:
(1) renal colic or back pain
(2) dysuria
(3) asymptomatic
(4) stones may or may not be evident on CT scan or other imaging studies
(5) oliguria
Laboratory findings:
(1) rising serum BUN and creatinine
(2) microscopic or gross hematuria
(3) increased white blood cells in the urine sediment (pyruria), occasionally with eosinophiluria
(4) crystalluria (positively birefringent plates, fans, starburst forms)
(5) analysis of the urinary stone does not indicate an alternative type of stone
Management:
(1) Replace any volume depletion and maintain hydration during diuresis.
(2) Diurese to increase urine flow.
(3) Discontinue or reduce dose of indinavir until renal function restored. Therapy can usually be restarted.
(4) Acidifying the urine may be difficult.
(5) Rare cases may require temporary dialysis with most cases reversible on drug discontinuation and diuresis.
Prevention:
(1) Drink at least 2 liters of fluid daily, with additional volumes in hot weather, with exercise and febrile illness.
(2) Avoid excessive dosing, especially with concurrent renal disease.
(3) Regular monitoring of renal function.
