The composition of urinary stones in the Sudan.

Seventy-eight urinary stones from the Sudan were analysed quantitatively; 75.6% of upper urinary tract (UUT) stones and 37.8% of lower tract (LUT) stones were composed of pure calcium oxalate monohydrate. The composition of adult UUT stones in the Sudan is almost identical to that of similar stones from Leeds except that the former contain much more calcium oxalate and much less calcium phosphate. A smaller proportion of adult LUT stones from the Sudan contain magnesium ammonium phosphate and a larger proportion contain uric acid/urate than similar stones from Leeds. Juvenile LUT stones from the Sudan probably contain more calcium oxalate and less uric acid/urate than juvenile bladder stones in some other developing countries.