Background Hypercalciuria has been considered as a predisposing factor for recurrent urinary tract infection (UTI) in recent studies. The mechanism may be related to uroepithelial injury by calcium microcrystals. The aim of this study was to evaluate the association of idiopathic Hypercalciuria with recurrent UTI in children.
Methods In this analytic study urine calcium:creatinine ratio of 40 children at the age of 2–16 years with recurrent urinary tract infection (without urinary tract anomalies and voiding dysfunction) was compared with 40 age and sex matched healthy children. Calcium:creatinine ratio more than 0.2 in a spot urine test was considered as hypercalciuria. Cases with hypercalcemia were excluded from the study. Recurrent UTI was defined as at least 3 episodes of UTI during 1 year or 2 episodes in 6 months.
Results Mean age of patients was 5 ± 2.22 years and mean age of control group was 5.13 ± 1.98 years. The mean calcium:creatinine ratio in case group (0.21 ± 0.17) was significantly higher than control group (0.08 ± 0.08) (p < 0.05). Hypercalcuria was detected in nineteen out of forty patients in case group (47.5%) and in 7.5% of control group (p < 0.001). History of familial urolithiasis was positive in 21% of hypercalciuric patients. There was not any significant difference in frequency of urinary symptoms between hypercalciuric and normocalciuric patients with recurrent UTI.
Conclusion Children who suffer from recurrent UTI in spite of absence of urinary tract anomalies should be checked for hypercalciuria. Control of hypercalciuria with low salt regimen and high fluid intake and treatment with hydrochlorothiazide may decrease UTI episodes.