Kidney stones are becoming more common in children where previously they were generally seen in adults.
Kidney stones are hard mineral deposits that generally form in the kidneys and may pass into the ureter and bladder in the urinary system. They can affect any part of the urinary tract. Stones can also form in the bladder, but these are not as common as those starting from the kidney.
Stones are painful when they pass, so if parents suspect that their child has one, they should not hesitate to take their child to the doctor.
Causes of Kidney Stones
There is no single cause of kidney stones. When the urine has crystal-causing substances that are at a higher concentration than the fluid, stones can form.
Possible risk factors include:
- Family history of kidney stones
- Eating too much sugar, sodium, or protein
- History of digestive tract surgery or disease
- Anatomic risk factors that may block urine flow (blocked kidney, ureter, or bladder)
- Some bacteria that cause urine infections can cause stones to form.
- Certain medical conditions, where your child may have limited movement, inherited kidney diseases such as cystinuria or renal tubular acidosis or certain treatments for severe seizures may increase your child’s risk for stone formation.
There are different types of kidney stones, including:
- Calcium type stones are typically in the form of calcium oxalate or calcium phosphate. This could be due to dietary factors, metabolic conditions, or certain seizure medications, such as topiramate, felbamate, or ketogenic diet.
- Cystine stones are usually seen in people with cystinuria, a hereditary disorder.
- Struvite stones may occur as the result of a urinary tract infection or other infection.
In some cases, symptoms are not present until the kidney stone goes into a ureter or starts to move around inside the kidney.
- The most common symptoms is severe intermittent side or back pain that is sudden in onset.
- Nausea and vomiting is common.
- Blood may be seen in the urine that is brown, pink, or red.
- Fever and chills may occur.
- Signs of a possible UTI with fever, chills, foul smelling urine or burning pain with urination.
- As the stone passes lower into the ureter near the bladder, your child may have urinary frequency, void only a small amount with urinary urgency, groin or inner thigh pain.
Some stones are found before there are any symptoms and only found with evaluation for possible UTI or as an unexpected finding on an x-ray or ultrasound test done for some other reason.
Once the doctor evaluates the child and learns about their medical history, there are some diagnostic tests that they may perform:
- The stones are diagnosed with plain X-ray of the abdomen and with an ultrasound in most cases.
- Sometimes a Computerized Tomography (CT) study is needed to make sure that there is a stone when there is some question of the cause of the pain and sometimes the CT scan may be needed to help determine the best treatment for the stone.
Treatment of Kidney Stones
- If the stone is small, the doctor will try to help your child pass the stone by having them drink a large amount of water to help the stone pass on its own. Pain medications will be recommended to help make your child comfortable ( such as ibuprofen or naproxen) and medications to help prevent nausea may be needed to help your child as well. Occasionally, tamsulosin, an alpha blocker medication, may be tried to help the stone to pass.
- Surgery to physically remove the stone if it does not pass on its own or if it is too large (generally larger than 7-10 mm) to pass on its own. This can be through a variety of surgical procedures including percutaneous nephrolithotomy, ureteroscopy with basket retrieval, or using a laser or extracorporeal shock wave lithotripsy (ESWL) to break up the stone.
Once your child’s stone has been treated, it is important to try to prevent new stones from forming.
Once the stone is treated or passed, your child’s doctor will try to determine why a stone formed in the first place and to try to prevent more stones by getting:
- Urine collection for 24 hours can show if the child’s urine contains high levels of stone-forming substances.
- Blood testing can look at potential metabolic causes for stone formation.
- Saving the stone that has passed is important so that it can be analyzed to see what kind of stone it is and to try to find ways to prevent stones from happening again.
Your child should try to drink more fluid throughout the day to prevent dehydration. Limiting salt or sodium intake in the diet and trying to limit sugary drinks such as soft drinks or sodas and dark caffeinated sodas will lessen your child’s chance of making more stones and help limit their risk for obesity which is a major risk factor for stone formation in children and adults.