The relationship between urinary bilharziasis and urolithiasis in the Sudan.

Nine hundred and ninety-seven Sudanese patients presenting to a urological unit in Khartoum were divided into a group consisting of 144 patients with a history or evidence of urinary bilharziasis and a second group of 853 patients with no history or evidence of this disease. Thirty-one per cent of the patients with bilharziasis and 32% of those without were found to have urinary calculi. In the bilharzial group there were recurrent stones in 7% compared with 12.4% in the non-bilharzial group. In the bilharzial group the stones were renal in 63.6%, ureteric in 27.3% and vesical in 9.1%, while in the non-bilharzial group 57% were renal, 30% ureteric and 13% vesical. Comparison of the incidence, rate of recurrence and site of stones in both groups suggests that urinary bilharziasis does not contribute to the high incidence of urolithiasis in the Sudan.