ABSTRACT
OBJECTIVE: To investigate the clinical characteristics of urolithiasis, retrospectively, in children who ingested melamine-poisoned formula as infants, and report a 5-year follow-up analysis. MATERIALS AND METHODS: Clinical data on 207 patients (mean ± standard deviation, 13.6 ± 8.0 months) with melamine-induced urolithiasis were retrospectively analyzed. Patients were subdivided into 2 groups according to treatment. A 5-year follow-up study was conducted with 95.7% (198 of 207) of the children. Ultrasonography, renal function evaluation, and urinalysis were analyzed. RESULTS: A total of 149 (72.0%) patients accepted conservative treatment. Fifty-eight (28.0%) patients accepted surgical intervention after conservative treatment proved ineffective. Of the 48 patients in whom retrograde ureteral catheterization was performed, 33 discharged the stone successfully, 4 had residual stones, 2 were switched to percutaneous nephrolithotripsy, and 9 underwent ureteroscopic lithotripsy. Six patients underwent extracorporeal shock wave lithotripsy, and other 4 patients underwent ureteral lithectomy. The age of onset, clinical presentations, size and location of stones, renal function, and mean time of hospitalization in patients with surgical intervention were significantly different from those of patients who accepted conservative treatment only (P < .001). The main component of the 12 melamine-contained stone samples was urate. The results of 5-year follow-up (mean ± standard deviation, 72.7 ± 4.1 months) study in 198 children did not show any significant difference of stone residue, renal function, and urinalysis between 2 groups. CONCLUSION: If the stones were treated appropriately in patients with melamine-induced urolithiasis, there is no medium-term risk for stone formation. Still, a longer time follow-up study is required to determine if there is any long-term poisonous effect on these patients.
