Pediatric urolithiasis--evaluation of risk factors in 95 children.

OBJECTIVE: Pediatric urolithiasis is a rarely encountered pathology, except in endemic areas such as Turkey. As a recurrent pathology which may reveal functional as well and morphologic changes in the urinary tract, metabolic and environmental factors, in addition to urogenital abnormalities, should be evaluated thoroughly in each patient. In this prospective study, the patient and family histories of 95 children with stone disease were evaluated, together with serum and urine risk factors.

MATERIAL AND METHODS: Between 1996 and 2001, 95 children (25 females, 70 males; mean age 7.3 years; age range 0.6-15 years) referred to our department with urolithiasis were evaluated. All patients were investigated with respect to stone localization, associated abnormalities, urinary tract infection (UTI), positive family history and serum and urine risk factors. In addition to standard risk factors (hypocitraturia, hypercalciuria, hyperoxaluria, hyperuricosuria, hypomagnesuria), diet and 24-h urine volume were also assessed in all children. Children with cystinuria were excluded from the study.

RESULTS: Stone size ranged from 0.3 to 3.3 cm, with an average value of 2.0 cm. The localization of the stones was classified as unilateral single stone in 37 patients, multiple unilateral stones in six and bilateral multiple stones in 27. Hypocitraturia was the commonest risk factor detected in our patients. A positive family history was present in 51 cases (54%). In addition, UTI was present in 59 cases (62%) and 67 cases had a previous history of recurrent UTI. Associated urogenital abnormality was detected in nine cases (9.4%). There were significant correlations between stone size and urinary citrate excretion (p < 0.05) and between the presence of UTI and urinary phosphate excretion (r = 0.59, p = 0.047). Treatments used were open surgery in seven (7.3%) cases, extracorporeal shock-wave lithotripsy in 39 (41%) and endoscopic surgery in 20 (21%). Following these procedures, 39 (41%) patients were completely stone-free, 11 (11%) had residual stones (<5 mm in diameter) and 12 (14.8%) passed the stone(s) spontaneously. During follow-up, regrowth was seen in four (4.2%) patients and stone recurrence was noted in a further four (4.2%).

CONCLUSIONS: In addition to stone removal, treatment of pediatric urolithiasis requires a thorough metabolic and environmental evaluation of all patients on an individual basis. Obstructive pathologies have to be corrected immediately and apparent metabolic abnormalities should also be treated. Children with a positive family history should be followed carefully with respect to stone recurrence. Urine volume increases in parallel with body mass index and medical therapeutic agents which increase urine citrate levels should be encouraged.