Resolution of Acute Renal Failure in Toxoplasmic Encephalitis Despite Continuance of Sulfadiazine

A patient with AIDS and toxoplasmic encephalitis treated with pyrimethamine and sulfadiazine became hypovolemic and developed acute renal failure. Diagnostic sulfadiazine crystals were abundant in the urine, and ultrasound examination demonstrated sludge and stones, presumably due to sulfadiazine. Renal failure resolved rapidly with hydration and administration of alkali, despite continued administration of sulfadiazine. The relatively old literature concerning crystalluria and renal failure due to sulfonamides is reviewed briefly, since complications due to use of poorly soluble sulfonamides probably will become more widespread as toxoplasmic encephalitis becomes more prevalent.