UPPER URINARY-TRACT STONE ANALYSIS USING X-RAY-DIFFRACTION - RESULTS FROM A TERTIARY REFERRAL CENTER IN NORTHERN INDIA

Background. The spectrum of urinary stone disease has changed consider ably in India from the common childhood bladder stone to the more freq uent upper tract calculi, We analysed the gravel retrieved from the up per urinary tract using X-ray diffraction analysis in an attempt to ev aluate the composition of the stones, Methods. We analysed 434 upper u rinary tract calculi from May 1993 to June 1994 obtained endourologica lly, as well as by extracorporeal shock wave lithotripsy and open surg ery, The stones were analysed using a Phillips compact X-ray diffracto meter (PW1840). The PC-APD software was used for data collection and p eak search. The phase matching was done by the software using the JCPD S reference database, Results. Oxalate stones comprised 97% of the tot al stones with calcium oxalate monohydrate forming 90% and calcium oxa late dihydrate and mixed stones forming the remainder, Struvite stones were found in 1.4%, while uric acid and apatite stones were less than 1%, There were no cystine calculi, Seventy per cent of calcium oxalat e monohydrate and 40% of calcium oxalate dihydrate stones were pure. A ll the struvite and apatite calculi were almost pure, Only 15% of stag horns did not consist of oxalate. Nine of the ten stones in children w ere of the calcium oxalate monohydrate variety. The stone composition in females was similar to that in males. Conclusions. X-ray diffractio n data indicate that urinary stone disease in north India is different from that in the western world. Calcium oxalate monohydrate stones pr edominate. These stones are hard to break and have a different metabol ic origin from those consisting of calcium oxalate dihydrate. These fi ndings might help in selecting the most appropriate method of treatmen t in north India and they indicate directions in which further metabol ic studies might be planned.