Phenacetin abuse and chronic pyelonephritis.

A history of phenacetin abuse has been found almost three times more frequently among subjects diagnosed on clinical and functional grounds as suffering from chronic pyelonephritis than among those suffering from other renal diseases or among non-renal controls. The chronic pyelonephritis in subjects admitting phenacetin abuse has been usually characterized by a more frequent intense bacteriuria and leucocyturia, by a slightly more frequent haematuria, history of renal colic, presence of stones and more rapid downhill course of glomerular filtration rate than in subjects without phenacetin abuse. A sterile lesion also without any past evidence of infection was observed only in subjects with the heaviest analgesic abuse. The discontinuation of the abuse in 5 subjects led to an improvement of the renal function.