Obituary to analgesic nephropathy--an autopsy study.

BACKGROUND: To determine whether classic analgesic nephropathy with renal papillary and urothelial capillary sclerosis could still be detected at autopsy in the beginning of the 21st century, the present study which is similar to a previous one performed in 1980 was undertaken as suggested by the Ad Hoc Committee of the International Study Group on Analgesics and Nephropathy.

METHODS: Consecutive autopsies of 616 adults performed at the Basle Institute of Pathology between November 2000 and February 2002 were analysed. Tissue samples of renal cortex and papilla of 1220 kidneys and of each ureter and main renal artery available were subjected to a very careful and meticulous study using classical histopathological methodology.

RESULTS: A number of lesions was found macroscopically but not a single case of papillary necrosis or analgesic nephropathy could be detected preceding histological analysis. Histologically, the most frequent lesions were vascular in 57.8% of kidneys followed by glomerular lesions in 13.1% (mostly diabetic glomerulosclerosis). Tubulo-interstitial lesions, mostly pyelonephritis were detected in 9.3% with only a single case of classic analgesic nephropathy with bilateral complete papillary necrosis and ureteral capillary sclerosis in a female who had received a renal transplant 14 years before her demise at the age of 67. In another five cases, complete papillary necrosis was detected associated with pyelonephritis, hydronephrosis or in completely shrunken kidneys. However, in the absence of capillary sclerosis, a histopathological diagnosis of classic analgesic nephropathy could not be made in any of these five cases.

CONCLUSIONS: The Basle autopsy prevalence of analgesic nephropathy decreased continuously from some 3% in 1980 to 0.2% in 2000 as shown by the present study. Similarly, capillary sclerosis of the urinary tract, the initiating event in the pathophysiology of papillary necrosis and analgesic nephropathy and the histological hallmark of the effect of toxic metabolites of phenacetin in analgesic abusers decreased from 4% of autopsy cases between 1978 and 1980 to the single case of the present study observed at the end of 2000. Thus, the classic analgesic nephropathy has disappeared some 20 years after the removal of phenacetin from the analgesic market despite the fact that mixed analgesics containing paracetamol, the main metabolite of phenacetin, have continued to be popular and widely used drugs.