Kidney stones (nephrolithiasis) are hard masses formed from concentrated minerals and salts that accumulate in the kidneys. While historically considered an adult condition, the incidence of kidney stones in children has been steadily increasing globally. These crystalline structures can cause severe symptoms if they migrate from the kidney and become lodged in the ureter, the tube connecting the kidney to the bladder. Immediate medical evaluation from a pediatric specialist is necessary upon suspicion of a stone. This article provides general information and does not replace professional consultation with a pediatric urologist or nephrologist.
Recognizing Symptoms and Initial Steps
The presentation of kidney stones varies significantly depending on the child’s age, location, size, and movement of the stone. Older children and teenagers often experience symptoms similar to adults, including the sudden onset of intense, sharp pain (renal colic) in the side, back, or lower abdomen. This pain may radiate toward the groin and typically comes in waves as the body attempts to move the stone.
Younger children may present with less specific signs, such as general irritability, an inability to get comfortable, or unexplained abdominal pain. Other common indicators include nausea and vomiting, which can quickly lead to dehydration, and changes in urination patterns. Parents may notice blood in the urine (hematuria), or the child may report pain while urinating or a constant urge to go.
Immediate care is necessary if a child experiences severe, unmanageable pain or if the stone is accompanied by fever and chills, which may signal a urinary tract infection or obstruction. Diagnosis typically begins with a urinalysis to check for blood, infection, or mineral crystals, followed by blood tests. Imaging usually starts with a kidney and bladder ultrasound to identify the stone’s size and location without radiation exposure. A computed tomography (CT) scan is highly accurate but is generally reserved for complex cases or surgical planning to minimize radiation in pediatric patients.
Non-Surgical Stone Management
If a kidney stone is small (typically less than 5 millimeters) and is not causing a complete blockage or infection, the initial approach is often non-surgical. This strategy, known as “Watchful Waiting” or Medical Expulsive Therapy (MET), focuses on facilitating the stone’s natural passage while managing pain and hydration. The goal is to avoid invasive procedures, allowing the body to expel the stone naturally.
Aggressive hydration is foundational, as increased fluid intake helps dilute the urine and increase its volume, effectively flushing the stone through the urinary tract. Children are encouraged to drink large amounts of water; intravenous (IV) fluids may be necessary if persistent vomiting prevents oral intake. Teenagers may require six to eight 8-ounce glasses of water daily, while younger children follow specific physician guidance.
Pain control is managed using non-steroidal anti-inflammatory drugs (NSAIDs) or prescription pain relievers for intense discomfort. Controlling pain is important for comfort and to prevent the nausea and vomiting that often accompany renal colic spasms.
MET often includes alpha-adrenergic antagonists (alpha-blockers) to relax the smooth muscles of the ureter. By widening the ureter, these medications (such as tamsulosin or silodosin) can decrease the time it takes for the stone to pass and reduce the need for pain medication. Alpha-blockers are particularly effective for stones located in the distal (lower) ureter, offering a less invasive option.
Interventional and Surgical Treatment Options
Active intervention is necessary if a stone is too large to pass naturally, causes persistent obstruction threatening kidney function, or is associated with an uncontrollable infection. Pediatric urologists use several minimally invasive techniques tailored to the child’s anatomy. The choice of procedure depends heavily on the stone’s size, location, and composition.
Extracorporeal Shock Wave Lithotripsy (SWL)
SWL is a non-invasive treatment using focused sound waves to break the stone into smaller, passable fragments. Directed using ultrasound or X-ray guidance, the procedure is performed under anesthesia. SWL is often the preferred first-line treatment for smaller kidney stones (less than 1 centimeter) because it avoids incisions and allows the child to return home the same day.
Ureteroscopy (URS)
URS involves passing a thin, flexible telescope (ureteroscope) through the urethra and bladder, up into the ureter or kidney. Once the scope reaches the stone, the physician can grasp it with a tiny basket or use a laser to fragment it into minute pieces. URS is a primary option, offering high clearance rates for stones throughout the ureter and kidney, especially when SWL is unsuitable or has failed.
Percutaneous Nephrolithotomy (PCNL)
PCNL is a more involved procedure reserved for large or complex stones (greater than 2 centimeters) or those that have failed other treatments. Surgeons make a small incision in the child’s back to create a tract directly into the kidney’s collecting system. A specialized scope is inserted to remove the stone whole or break it up and suction out the pieces. PCNL offers superior stone clearance for stones larger than 15 millimeters compared to URS and SWL.
Preventing Future Stones
Long-term management focuses on preventing recurrence, which is a significant risk. A stone analysis, performed after the stone has passed or been removed, determines its chemical composition to guide prevention strategies. The most common types are calcium oxalate, calcium phosphate, uric acid, and cystine stones, each requiring a different dietary or medical approach.
The primary lifestyle change for prevention is maintaining a consistently high fluid intake, primarily water, to keep the urine dilute. Dilute urine decreases the saturation of crystal-forming substances like calcium and oxalate. Children should be encouraged to drink water throughout the day, not just when they feel thirsty.
Dietary modifications are tailored based on the stone type identified. For children with calcium stones, reducing sodium intake is necessary because high sodium levels increase calcium excretion in the urine. Parents should aim to reduce processed foods, fast foods, and canned goods, which often contain excessive sodium.
For calcium oxalate stone formers, a reduction in foods rich in oxalates (such as spinach, rhubarb, nuts, and chocolate) may be recommended. Conversely, children should consume beverages containing naturally occurring citric acid, like lemonade, as citrate helps prevent stone formation by binding to calcium in the urine. Specialized follow-up care with a pediatric nephrologist or urologist is necessary to monitor metabolic risk factors and manage medications, such as potassium citrate, to prevent future episodes.