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Case 3: Indinavir Nephrotoxicity

You answered:

A The patient probably had bacterial cystitis caused by an organism resistant to trimethoprim-sulfamethoxazole, and now the infection has evolved into pyelonephritis and should be treated with ciprofloxacin (Cipro).

This answer is incorrect. Crystalluria associated with dysuria or renal colic in the absence of nephrolithiasis occurs in approximately 5 to 8% of patients treated with indinavir. The crystalluria-dysuria syndrome may be misdiagnosed as infectious cystitis, leading to unnecessary antimicrobial therapy. Urinalysis will reveal crystals with or without leukocytes, and bacterial cultures will be negative.

Choose another answer:

B The absence of stones on the CT-KUB scan rules out nephrolithiasis caused by indinavir.
C The patient likely has indinavir-induced nephrolithiasis and should immediately be referred to urology for lithotripsy.
D The patient likely has indinavir-induced nephrolithiasis and antiretroviral therapy should either temporarily be discontinued or changed to a different regimen that does not include indinavir. The patient should initially be managed conservatively with hydration and pain control.

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