[Clinical thinking and decision making in practice. A patient with flank pain and anuria]

A 49-year-old man was admitted because of acute anuria. He had bilateral loin pain and was said to have been suffering from renal calculi seven years earlier. He used diclofenac as a pain killer. The renal pyela were mildly dilated. Eventually it became clear that the patient suffered from retroperitoneal fibrosis. This case illustrates (a) ureteral patency does not ensure actual urine flow; (b) non-steroidal anti-inflammatory drugs (NSAIDs) are a frequent cause of renal function loss, but only if there is an additional renal disease causing increased renal prostaglandin synthesis; (c) pattern recognition and verification are clinically relevant diagnostic tools.