Pediatric Stone Disease and Endourology
Core concepts
Know the metabolic and anatomic causes of pediatric stones: hypercalciuria, hyperoxaluria, cystinuria, hypocitraturia, and anatomic obstruction. Stones in children are more often metabolic than in adults, so metabolic evaluation is important. Imaging: ultrasound first, low-dose CT when needed. Management depends on size and location: observation for small distal stones, medical expulsive therapy in selected cases, ureteroscopy for most ureteral stones, and percutaneous nephrolithotomy for large renal stones. Shock wave lithotripsy has a role but is limited by stone size and composition. Understand the role of hydration, dietary modification, and stone-specific medications. Endourologic principles: age-appropriate equipment, attention to ureteral caliber, and minimizing radiation. Recognize struvite stones in the setting of infection and uric acid stones in metabolic disorders.
Traps
- Assuming stones in children are rare and not metabolic; always evaluate metabolism.
- Using CT as first-line imaging in children instead of ultrasound.
- Forgetting that cystine stones are radiopaque and resistant to lithotripsy.
- Missing the need for metabolic evaluation after a single stone in a child.
Worked example
A 10-year-old with a 4 mm distal ureteral stone and no obstruction can be managed with hydration and observation; if it fails to pass, ureteroscopy is preferred over prolonged observation.
Rule of thumb
Ultrasound first, metabolic workup for every child, and size/location determine whether to observe or intervene.