The urinary system includes two kidneys (that filter urine), two ureters (that move urine from the kidneys to the bladder), the bladder (that holds urine), and the urethra (that carries urine out of the bladder).

Kidney stones develop when a collection of minerals, or other material, form a small "stone”. The stone can cause pain, block the flow of urine, and rarely, cause long-term kidney problems if it is not recognised and treated promptly. Fortunately, most children who develop kidney stones recover without any long-term complications.

Stones are less common in children than in adults. Most children who develop kidney stones have an underlying condition that increases their risk of stones, although some children develop a stone for unknown reasons.

The most common symptoms of kidney stones are; pain in the belly or back, blood in the urine, nausea or vomiting, and excess need to rush to the bathroom to urinate.

However, some children, particularly young children, do not have any symptoms, and the kidney stone is found when an imaging test (like an X-ray) is done for another reason.

Some kidney stone symptoms are similar to those of a bladder infection (also called a urinary tract infection). Your child’s doctor will need to perform an exam and do some testing to know what is causing the symptoms.

Certain factors can increase a child’s risk of developing kidney stones. Children who have had a kidney stone in the past have the highest risk of developing a stone in the future. Preventive measures can decrease the risk of developing a stone in the future. The amount of fluids a child drinks directly affects the amount of urine the body makes. Drinking a small amount of fluids means that the kidneys make a small amount of urine, which increases the concentration of stone-forming substances in the urine. Drinking more fluids can reduce the risk of recurrent stones. Having congenital (from birth) abnormalities in the kidneys, ureters, or bladder can increase the risk of developing a kidney stone. Some medicines increase the risk of forming crystals in the urine. Several uncommon inherited disorders can increase a child’s risk of developing kidney stones. Testing for these disorders might be recommended. Children with a disease called cystic fibrosis are at higher risk of developing kidney stones.

If your child has any of these symptoms of a kidney stone, he or she should see a doctor as soon as possible. The doctor will do an exam and order urine testing.

If a stone is likely, based on the exam and urine tests, he or she will order an imaging test, like a CT scan, ultrasound, or X-ray. The imaging test can show the exact size and location of the stone, which will help guide treatment.

Treatment is different for each child. The right treatment depends on the severity of the condition

If the stone is small and causes only mild symptoms, the child might be allowed to stay home, drink a lot of fluids and he or she might also need over-the-counter medicine for pain as they wait for the stone to pass in the urine on its own.

If the stone is big or the child has severe symptoms, they may be hospitalised and various types of medicines can be prescribed to dissolve and help the stone pass, alleviate with the bothersome symptoms or both.

If your child gets a kidney stone, he or she has a higher risk of getting another one later, about 30 to 65 per cent chance of recurrence. To help keep this from happening, make sure your child drinks plenty of water.

Your doctor will do tests to find out what caused the first stone. Depending on the results, you might need to change what your child eats. If so, the doctor can tell you which foods your child should eat, or not. He or she might also prescribe new medicines to keep your child from having another kidney stone.

Dr. Ian Shyaka Resident in Surgery, Rwanda Military Hospital, iangashugi@gmail.com