The incidence of pediatric urinary stones in the United States is less than 2% that of the adult population. Stone disease in the United States and Scandinavian countries is usually related to metabolic disorders. Hypercalciuria, or elevated calcium in the urine, has been increasingly identified as a significant metabolic risk factor for stone disease. The most commonly seen stone type is calcium oxalate stone. These children are usually older, and clinically present in a similar fashion to the adult stone formers.
In the Middle and Far East countries including Thailand and India, endemic stones are very common. These stones are generally composed of ammonium acid urate and oxalate. These stones typically occur in the bladder and are more common in males. They are also seen in lower socioeconomic groups.
In Europe, stone disease is less common than in the Far East, but more frequently seen than in the United States. Over 85% of stones occur in the kidneys and ureters, typically referred to as the upper urinary tract. Two thirds of these stones are infection related. The bacterial organism, Proteus mirabilis, is typically responsible for these stones in 75% of cases and usually result in magnesium ammonium phosphate stones. These stones are also known as struvite stones. The majority of these stones occur in males and are seen under 5 years of age. The recurrence of these stones is related to the inability of the patient to remain infection free.