A kidney stone is a small, hard deposit of mineral and acid salts that forms within the urinary tract. Some kidney stones are very small (about the size of a grain of sand), while others grow larger.
There are several different types of kidney stones, categorized by the type of mineral or acid salt they contain. The most common type is calcium oxalate, which accounts for 80% of kidney stones. Other types are: uric acid, struvite, calcium phosphate, and cysteine stones. It is important to identify and properly treat kidney stones, because they can obstruct the flow and drainage of urine.
If your child does not drink enough fluid, his/her urine can become concentrated which increases the chance for crystals to form.
A diet that is very high in protein, salt, fructose, or oxalate-rich foods (including leafy green vegetables, tea, or chocolate) can contribute to kidney stones. Additionally, up to 6% of children on ketogenic diets, for other medical reasons, will develop a kidney stone.
Children have a greater chance of developing stones if they have a parent or sibling who has also had a kidney stone.
An obstruction in the urinary tract prevents urine from flowing properly and emptying from the bladder, which can result in kidney stones.
About 15% of children who have had a bladder augmentation (enlargement) procedure will develop a bladder stone.
Children with a disorder related to the muscles and nerves in the urinary tract are at an increased risk for stones due to urinary stasis.
Teenagers are more likely to develop stones than younger children, and girls are affected more often than boys.
Metabolic disorders like hypertension and diabetes often times are associated with abdominal obesity and insulin resistance. The insulin resistance can lead to an increased risk of kidney stone formation.
Symptoms can vary, especially in children. Typical symptoms include flank pain, nausea, vomiting, abdominal pain, groin pain, blood in the urine, pain with urination, or urinary frequency.
However, sometimes children with stones do not have any symptoms at all. Some children may only complain of non-specific abdominal pain, or they might see small or large amounts of blood in the urine, without having pain elsewhere.
Your child's urologist will conduct a physical exam, medical history evaluation, and a urinalysis to help determine if kidney stones are present. Depending on the size, location, and number of stones, the urologist will determine which imaging study is necessary. Imaging studies that are helpful to diagnose kidney stones include: X-ray, renal ultrasound (RUS), and abdominal/pelvic CT scan.
We may ask your child to ‘strain’ his urine with a special filter so we can send the stone for testing, if necessary, to determine the type of stone.
We can treat stones in several ways, depending on their size, location, number and composition. Based on your child's specific needs, the urologist will recommend the most appropriate and effective treatment.
Most small stones can pass on their own, and do not require surgery. Your urologist may recommend medication:
Surgery may be necessary if your child experiences any of the following:
A follow-up renal ultrasound (RUS) or X-ray will usually be performed to ensure the stone is gone and the treatment was successful.
If your child has a stone, there is a 50% chance of having another stone within the next 5 years. To help us determine what caused the kidney stone, we may get some bloodwork and ask your child to collect urine for 24 hours to measure urine volume and levels of acidity, calcium, sodium, uric acid, oxalate, citrate, and creatinine. We will usually order these tests a few weeks after the symptoms and acute phase have resolved, ideally when the child is stone free. This is done to rule out any underlying metabolic disorder that may be contributing to stone formation.
There are ways to help your children avoid developing kidney stones. Make sure they drink plenty of water, and limit their intake of meat, salt, and foods that are high in oxalate. We may also recommend supplementing citrate in your child's diet to help prevent stones. Citrate is found in certain beverages such as Crystal Light, citrus fruits/juices, and it may also be prescribed for your child in pill form. Your urologist will discuss these options and recommendations with you.
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