Eosinophiliuria in the setting of renal injury should prompt suspicion of which condition?

• A. ACE inhibitors
• B. Diuretics
• C. Alport syndrome
• D. NSAIDs, sulfa drugs and other antibiotics

Answer: (D)

Eosinophiliuria points toward acute interstitial nephritis, a hypersensitivity reaction in the kidney interstitium. When this interstitial inflammation occurs, eosinophils can spill into the urine, and this is most commonly triggered by drugs. The classic offenders are NSAIDs, sulfa drugs, and other antibiotics, so finding eosinophils in the urine during renal injury strongly suggests drug-induced interstitial nephritis.

In contrast, ACE inhibitors cause kidney injury mainly through hemodynamic effects and aren’t typically associated with eosinophiluria. Diuretics can cause AKI for other reasons, but eosinophiluria isn’t a characteristic finding. Alport syndrome is a genetic nephritis that presents with hematuria and hearing loss, not eosinophiluria.