The radiological diagnosis of analgesic nephropathy.

A study was made of the radiological findings in 57 patients with a clinical diagnosis of analgesic nephropathy. The ages of the patients ranged from 27 to 72 years, and females predominated over males in the ratio 4-7 to 1. Renal failure varied from mild to very severe and the patients showed the usual high incidence of analgesic-induced gastro-intestinal, haematological and neurological disorders. In 82% of cases, kidneys were of normal size, but there was radiological evidence of reduced renal function in 85%. Thus, a small kidney with good renal function was unlikely to be due to analgesic nephropathy. Medullar necrosis was observed in 65%, and papillary atrophy and papillary necrosis each in 46%. Although usually gradual, acute massive sloughing of necrotic papillae could occur and occasionally led to ureteric obstruction. Papillary cavitation was seen in 39% but fistulae and ring shadows were observed in only 11% and 14% respectively, while renal calcification occurred in 26%. With the use of high dose techniques and retrograde pyelography, it is almost always possible to make a positive radiological diagnosis of analgesic nephropathy, even in patients with markedly reduced renal function.