Urolithiasis in Children—Clinical Picture, Pathogenesis, and Diagnostic Approach

As in adults, urolithiasis is a significant health problem in children from an early age, having a very negative impact on health and quality of life and potentially leading to kidney function impairment. The occurrence of deposits in the urinary tract in a child is almost always the result of significant predisposing factors, including metabolic defects involving the kidney or the entire body (often inherited in a Mendelian fashion), urinary tract defects, or urinary tract infections. Among metabolic disturbances, idiopathic hypercalciuria, preceded by hypocitraturia, is the most common one. Any child with nephrolithiasis requires a careful metabolic evaluation, including blood tests, urinalysis, and, in many cases, molecular diagnosis. This narrative review presents the epidemiology, pathophysiology, and diagnostic process in children with nephrolithiasis. Special emphasis is put on pathophysiological pathways leading to metabolic kidney stone disease and metabolic diagnostic steps in children with urolithiasis, as metabolic disturbances are the most common cause of recurrent urolithiasis in Europe and North America. Nephrolithiasis should be treated as a symptom of renal or systemic disorders, and in every child, the cause of these disorders should be sought to prevent recurrence.