Acute granulomatous interstitial nephritis due to co-trimoxazole

A 51-year-old man with diabetes mellitus and mild hypertension developed acute interstitial nephritis 4 days after starting a course of co-trimoxazole for bronchopneumonia. Following initial symptoms of overt hypersensitivity, he developed azotemia and renal tubular dysfunction with malaise and anorexia requiring hospitalization. Renal pathology demonstrated an acute granulomatous interstitial nephritis superimposed on chronic diabetic renal disease.