Renal stones in children
Historically, pediatric kidney stones have accounted for less than one in every 3,000 pediatric admissions in the U.S. and about 2 percent of all stone disease. However, renal stones in children are on the rise. Researchers found that between 1999 and 2008, the proportion of kidney stones among all patients at children's hospitals increased about 10 percent a year. Lifestyle factors such as obesity, diets with excess salt and not drinking enough water are possible contributors to the increase.
Still, stones are relatively uncommon in children, and primary care physicians may have limited experience with this diagnosis. Symptoms of pediatric kidney stones include:
- flank pain
- abdominal pain (especially younger children)
- groin, testis or labial pain with ureteral stones
- gross hematuria
- microscopic hematuria
- urinary tract infection
- nausea and vomiting
- colic (infants)
Ultrasound tests are not as sensitive as computed tomography scans in detecting renal stones in children. However, ultrasound is very sensitive for the hydronephrosis associated with obstruction. Because ultrasound does not involve radiation exposure, ultrasound is recommended as the initial imaging test in all children suspected of having a stone.
Patients with small ureteral stones and no signs of infection can undergo a trial of spontaneous passage, with aggressive hydration and treatment with analgesics and anti-inflammatories. “Medical expulsive therapy” with alpha-blockers (tamsulosin, doxazosin) has been shown to increase spontaneous passage rates in adults and children. Smaller stones are most likely to pass:
- <4 mm: 80-90 percent pass
- 4-8 mm: 50 percent pass
- >8 mm: 10 percent pass
Paradoxical to adults, some evidence suggests that children may be more likely to pass larger stones, possibly due the increased tissue pliability, hormonal effects or other factors.
Pediatric patients with renal colic may need to be urgently admitted to a hospital if they have a fever or other evidence of infection, experience severe pain not controlled by oral analgesics, have persistent nausea and/or vomiting or show evidence of renal insufficiency or azotemia. Infection and severe pain or nausea may require temporizing measures, such as percutaneous nephrostomy or an internal ureteral stent.
Surgery may be required in the following cases:
- obstructing stones that fail medical therapy
- large stones, staghorn stones
- infection stones
- asymptomatic renal calculi, particularly if they increase in size
Surgical approaches include extracorporeal shock wave lithotripsy, ureteroscopic surgery, percutaneous surgery and open stone surgery.
For more information, contact Boston Children's Department of Urology at 617-355-7796.