Acute kidney injury from pyelonephritis in an elderly man: case report.

Pyelonephritis is rarely considered in the differential diagnosis of acute kidney injury. Acute non-obstructed bacterial pyelonephritis is an infrequent and rarely considered cause of rapidly progressive acute kidney injury. A diagnostic challenge thus develops as it is difficult to clinically differentiate acute kidney injury secondary to ischemic or toxic acute tubular necrosis or papillary necrosis versus acute interstitial nephritis secondary to drugs or infectious pyelonephritis. We describe a case of acute kidney injury due to suppurative pyelonephritis in an elderly immunocompetent man who presented with dysuria, vomiting, and fever and later found to have histologic and radiologic proven pyelonephritis as the cause of acute kidney injury in the absence of hypotension, nephrotoxic agents, non-steroidal analgesics, immunosuppression, urinary tract obstruction, or other structural anomalies. The patient was managed with antimicrobial therapy, hemodialysis, and a short course of corticosteroids.