Urinary stones, or calculi, are seen in adults more often than in children. They result when a chemical in the urine crystallizes and grows to form a stone. Most stones are composed of calcium, but others may be made of uric acid, oxalate or even certain medications. Unlike adults, children with kidney stones are more likely to have an underlying medical problem, such as urinary tract infections, inflammatory bowel disease or certain genetic diseases.
Symptoms of Kidney Stones
Blood in the urine is the most common symptom, followed by abdominal pain that is sometimes accompanied by nausea and vomiting. Kidney stones by themselves don't usually cause pain unless they pass down into the ureter (the portion of the urinary tract between the kidney and bladder), causing blockage of the urine flow. If an infection of the urinary tract is also present, the child may develop fever.
Diagnosis of Kidney Stones
A spiral computed tomography (CT) scan is generally the most accurate test for diagnosing kidney stones. This is a noninvasive X-ray study that takes only a few minutes and does not require an injection of dye. However, CT does involve exposure to radiation, so your child's doctor may choose to perform an ultrasound instead. Ultrasound is also noninvasive, but is not quite as sensitive as CT for finding stones, especially if they're small.
Most stones smaller than six millimeters (about the size of a small pea) will pass on their own. During this time, the child is treated with oral fluids and pain medicines. If the child cannot drink, or has severe pain or fever, he or she may need to be admitted to the hospital until the stone passes or is removed. Sometimes the pediatric urologist will place a tube or stent in the ureter (the portion of the urinary tract between the kidney and bladder). This procedure, done under anesthesia, clears any obstruction and relieves pain while gently stretching the ureter to allow the stone to pass. The stent is usually removed after a few weeks.
If the stone doesn't pass out of the kidney, it can be treated with extracorporeal shock wave lithotripsy (ESWL). While the patient is under anesthesia, X-rays are used to target the stone. Shock waves are then focused on the stone to break it up into pieces small enough to pass on their own.
In other cases, depending on the size, composition and location of the stone, the pediatric urologist might find it necessary to surgically remove the stone. This can be done via ureteroscopy, in which is a small scope is passed through the urethra, into the bladder, and up the ureter. The stone can then be removed with special instruments or broken up with a laser. If a kidney stone is very large, a scope can be passed directly into the kidney through a tiny incision in the back, then broken up or removed. This is done in a procedure called percutaneous nephrolithotripsy, or PCNL.
Very rarely, stones may need to be removed directly with laparoscopic or open surgery via a larger incision.
Prevention of Kidney Stones
The biggest risk factor for stone disease is a history of prior episodes of stones. Once any acute problems such as infection or blockage are treated, the child undergoes a metabolic evaluation by a pediatric nephrologist. This consists of a series of urine and blood samples, often before and after dietary changes. A treatment program to prevent further stones can then be tailored to the child's particular problem. In many cases, all that is required is increased water intake.
Pediatric Urology at Cedars-Sinai
Children are affected by different urologic conditions than adults, and their smaller bodies respond differently to anesthesia and surgical incisions. For these reasons, the Cedars-Sinai Urology Academic Practice is guided by the philosophy that pediatric patients are best evaluated and treated by pediatric specialists. Andrew Freedman, MD and Barry Duel, MD, the Urology Academic Practice's pediatric urologists, devote their practice to the evaluation and treatment of children. Both are board certified in Pediatric Urology, and offer broad experience in minimally invasive laparoscopic procedures. Dr. Barry Duel is experienced in robotic procedures adapted for the needs of children. The majority of their procedures are conducted on an outpatient basis, with both outpatient and inpatient surgeries attended by specialized pediatric anesthesiologists.