Chronic tubulointerstitial nephritis caused by recurrent myoglobinuria.

A 42-year-old man with McArdle's disease had numerous episodes of pigmenturia, but had only one proved episode of acute renal failure that required dialysis. A renal biopsy performed one month after complete recovery from that nephrotoxic event showed severe tubulointerstitial fibrosis. These findings suggest that, while acute renal failure may be an infrequent complication, repeated episodes of myoglobinuria may initiate subclinical nephrotoxic insults, resulting in chronic tubulointerstitial nephritis.