Urolithiasis in infants: evaluation of risk factors.

OBJECTIVE: Urolithiasis in infants is not a very rare situation in Turkey, and the incidence has been increasing in recent years. The purpose of this paper was to investigate the clinical characteristics, metabolic and anatomic risk factors for urolithiasis and microlithiasis in infants. METHODS: The cases of 178 infants (63 girls, 115 boys), who were referred to our department between 1999 and 2009 with urolithiasis, were evaluated. RESULTS: The mean age at diagnosis of stone disease was 11.5 months (range, 10 days-24 months). The mean follow-up duration was 33.6 months (1.2-110 months). The major clinical symptoms of our patients were restlessness in 24 children (13.5%) and vomiting in 23 (13%). Thirty-five infants (19.7%) had a urinary tract abnormality; vesico-ureteral reflux was the most common abnormality (12.9%). Hypercalciuria and hyperuricosuria were detected in 46 and 56%, respectively. Stone analysis was performed in 56 infants, and calcium oxalate was determined in 36 patients (64.3%). A family history of urolithiasis, presenting symptoms and underlying metabolic abnormalities were similar for patients with microlithiasis and those with larger stones. However, infants with microlithiasis had higher ratios for history of vitamin D administration and feeding with formula. Surgical treatment was performed in 42 infants and extracorporeal shock wave lithotripsy in 30 infants. CONCLUSION: Our results showed that urolithiasis in infants may present nonspecific symptoms and may even be asymptomatic and that a positive family history for urolithiasis, urologic abnormalities, metabolic disorders, urinary tract infections, vitamin D administration and feeding with formula may increase the occurrence of urolithiasis in infants.