Epidemiology of pediatric urolithiasis

The current epidemiology of urolithiasis in children has been described in numerous surveys conducted in various countries showing different patterns of the disease. A pattern of relatively rare calcium-based upper tract stones is prevalent in children from industrialized countries. Endemic bladder stones, composed of uric acid and calcium oxalate in the presence of sterile urine, are typical of children living in developing countries, especially in rural areas. However, the incidence of endemic bladder stones is gradually decreasing, as poverty and infantile malnutrition disappear and affluence spreads to all social classes. Other patterns of urolithiasis can also be observed in relation to genetic and socioeconomic or climatic factors. Cystinuria and hyperoxaluria account for up to 5-15% of pediatric stones. Infection stones, mainly composed of struvite and carbonate apatite, are associated with chronic infection and often related to poor health conditions. In particular, boys are prone to infected stones, although this type of calculi is decreasing in Western countries. Upper urinary stones composed of calcium oxalate mixed with calcium phosphate and uric acid are becoming frequent in tropical regions where the risk of stone formation is compounded by low urine volume. Prematurity, neurological problems, ketogenic diet, and reconstructed or augmented bladders are increased risk factors for stones in babies.