Renal and Ureteric Stone Composition: A five year retrospective study for Northern Ireland

INTRODUCTION: The study aimed to present the types of renal and ureteric stones (calculi) present in the population of Northern Ireland. The data may help in future planning treatment of stone services, patient education and prevention. METHODS: Consecutive retrospective renal and ureteric stones analysed over 5.75 years (January 2008 – September 2013) in Northern Ireland. Exclusions included patients < 16 years, and calculi listed as bladder stone. RESULTS: Total of 1618 stones analysed. Male to female calculi ratio 1.93: 1. Age range 16 – 94 years (52.2 mean), most common age for stone analysis 31–60 years. From 2008 to 2012 the number of stones analysed increased by 132.9%. Calcium was demonstrated in 94.5% (1529) of stones, of which 2.5% (40) pure calcium oxalate. Calcium oxalate and phosphate 72.9% (1182) of all stones, male to female ratio 2.4:1. Stones containing uric acid 9.6% (156), with uric acid male to female ratio 4.83:1. Struvite 13.7% (222), male to female ratio 1:1.6. Pure cystine 1.1% (18) of stones, male to female ratio 1:1.3. CONCLUSION: There is a high proportion (94.4%) of stones containing calcium oxalate in Northern Ireland; these patients should be aiming to produce 2L of urine a day to aid prevention. Most common age for stone analysis (31–60) is in keeping with most common age for presentation. The steep increase in calculi analysis of 132.9% must be met with personalised stone treatment and prevention strategies.