Is there unique difference in the type of renal stones in Northern Sri Lanka? Analysis of chemical composition of renal stones in Jaffna by infrared spectroscopy

Introduction
Renal stone disease is a common clinical problem in surgical practice. Renal stone is a common cause for obstructive uropathy and renal impairment. Because of differing “aetio-pathology”, kidney stones are usually mixtures of two or three or more chemical components. Analysis of chemical composition and type of renal stone could aid in the prevention and management of stone formation and its recurrence. The comparison of the prevalence   of renal stone types in Northern Sri Lanka with other geographical regions can help in the identification of possible environmental “geo-chemical” factors associated with nephrolithiasis.

Objective
The objective of this study was to analyse the chemical composition of renal stones in Jaffna by infrared spectroscopy. Age and gender of patients who had surgical intervention for renal stones and type and morphology of renal stones were considered for analysis.

Study design
This is an institutional based prospective “cross-sectional” analytic study. Following ethical approval, clinical profiles of patients were recorded. Chemical composition and type of the stones were analysed. Different stone types and stone morphologies were compared with available local and international data.  

Results
A total of 104 patients were surgically treated for nephrolithiasis during the study period. Their “ages” ranged from 20-70 years with the mean age of 48.21 years [SD 14.43]. Among them 77 [74%] were males and 27[26%] were females. Calcium oxalate, carbonate apatite, uric acid, cystine, struvite and calcium carbonate types of renal stones were found in 79 [75.9%], 7[6.7%],14[13.5%], 1[1%] 2[1.9%] and 1[1%] patients respectively.  86[83%] patients had pure stones and 18 [17%] had mixed stones. Staghorn calculi were found in 23 [22.1%] patients and non-staghorn calculi were found in 81 [77.9%] patients. Among the staghorn calculi, 16 [69.6%] were calcium oxalate and among the non-staghorn calculi 64 [79%] were calcium oxalate. Among 14 patients who had uric acid stone 10 of them had type II diabetes.

Conclusion
Calcium oxalate is the commonest renal stone type in Jaffna. Prevalence of uric acid type renal stone has increased in Jaffna over three decades.