Kidney stones in children

How common are kidney stones in children?

Kidney stones are often thought of as an adult disease, but in recent years they have been seen more and more often in children too. Azerbaijan has a hot climate and lies in a region where stones are more common. Stones can occur even in babies.

Unlike in adults, in children there is often a specific cause behind a stone: a metabolic disorder, a congenital anomaly of the urinary tract or an infection. So in a child, the stone should not only be removed; its cause must also be found.

Causes

• Metabolic: too much calcium in the urine (the most common cause), too little citrate, too much oxalate or uric acid, cystinuria.
• Anatomic: UPJ obstruction, megaureter, other conditions that cause urine to stagnate.
• Infection: some bacteria create conditions for stones to form in the urine.
• Lifestyle: drinking too little fluid, salty and processed foods, long periods of inactivity, some medications.

Symptoms

• In older children: severe, colicky pain in the flank that spreads to the lower abdomen (renal colic), nausea, vomiting, blood in the urine.
• In young children: there is often no typical pain. Irritability, crying, vomiting, a urinary tract infection, or the stone is found by chance on ultrasound.
• Recurrent urinary tract infections.

Diagnosis

• Ultrasound is the first test and in most cases the only one needed; it involves no radiation.
• Low-dose computed tomography (CT) when the stone is not seen on ultrasound or when an exact size is needed for the treatment plan.
• Blood and urine tests, 24-hour urine collection: to find the cause of the stone. Chemical analysis of a passed or removed stone gives very valuable information, so keep any stone that passes and bring it to the doctor.

Treatment

Small stones

Most stones smaller than 5 mm that are in the ureter pass on their own. During this time, pain relief, plenty of fluids and sometimes a medication that makes passing the stone easier are given. The child is monitored, and if the pain does not go away, a fever develops or the stone does not pass within a few weeks, an intervention is done.

Stones that need an intervention

Open surgery for stones is now almost never done in children. Methods that need no incision or are minimally invasive are used:

• Shock wave lithotripsy (ESWL). Waves delivered from outside the body break the stone into small pieces, which then pass with the urine. It works well for kidney stones up to 1–2 cm.
• Ureteroscopy and retrograde intrarenal surgery (RIRS). A thin endoscope is passed through the urethra, and the stone is broken up with a laser and removed. It is chosen for ureteral stones and some kidney stones.
• Percutaneous nephrolithotomy (PCNL, mini-PCNL). For large kidney stones, the kidney is entered through a small opening in the lower back and the stone is removed.

When blockage and fever occur together, the kidney is first drained with a temporary stent or drain, the infection is treated, and the stone is removed later.

Preventing recurrence

• Plenty of water: urine should be light in color. 1–2.5 liters a day depending on the child’s age, more in hot weather and after sports.
• Less salt: processed foods, chips, sausages and cold cuts.
• Do not cut calcium: dairy products should stay at normal amounts; reducing calcium actually increases the risk of stones.
• Water instead of sweet drinks: lemon juice increases citrate and may be helpful.
• Medication when needed, based on the metabolic workup.