Four cases of nafcillin-associated acute interstitial nephritis in one institution.

BACKGROUND: Over the course of 1 year, four patients in a single institution developed acute kidney injury most likely secondary to nafcillin-associated acute interstitial nephritis, indicating that this complication might not be as rare as is commonly believed. The main case presented here is that of a 73-year-old man with a history of chronic low back pain who presented with worsening back pain, as well as nausea, vomiting and volume depletion. Imaging studies revealed a soft tissue abscess in the left psoas major muscle. INVESTIGATIONS: Physical examination, complete urine analysis, blood and urine cultures, measurement of peripheral eosinophil and plasma creatinine levels, and renal ultrasound. DIAGNOSIS: Nafcillin-associated acute interstitial nephritis. MANAGEMENT: Discontinuation of nafcillin and provision of supportive care.