Kidney Stones

What are kidney stones?

A kidney stone is a hard mass that develops when chemicals in the urine crystallize or form into a stone within the kidney. The peak age for stones is between 20 years and 50 years, although they may also be found in children. People who have one stone are more likely to have more stones in the future.

Many stones are very small, about the size of grains of sand. These stones pass down the ureter into the bladder and out of the body through the urethra. Other stones may be pea- or marble-sized or be so large that they are unable to be passed out of the kidney. Some of these larger stones can block the ureter. Those with kidney stones often also have blood in their urine and/or pain on the side of the abdomen. Because kidney stone pain can be severe, it is not uncommon for children or adults to vomit.

What causes kidney stones?

In children, the cause of stones is not always known. Studies are completed by our office to help determine the causes of kidney stones in each child. Sometimes the urine will have too much or too little of certain elements that increase the likelihood of stones forming. Poor water intake can also play a vital role in the formation of stones, as can family history of kidney stones. Although uncommon, a metabolic disorder may be diagnosed in a child who forms stones. All possible causes will be looked at during a child’s visit.

What are the types of kidney stones?

These are three main types of kidney stones:

• Calcium stones are a common type of stone contains calcium. They are made of either calcium oxalate or calcium phosphate. The formation is linked to an increased level of calcium in the urine, possibly because of inherited or genetic factors.
• Struvite stones are made of magnesium and ammonia and are often related to urinary-tract infections.
• Uric acid stones form because of an abnormally high amount of uric acid in the urine.

What are the symptoms of kidney stones?

Kidney stones that block the flow of urine require treatment to prevent kidney damage. Large stones also may require surgery to remove the stone or break the stone into smaller pieces that a child can pass more easily. Children experiencing any of the symptoms below should see their doctor as soon as possible:

• Severe pain in the back or side, with or without nausea and vomiting.
• Pain that radiates down into the groin.
• Urine that is colored pink or tinged with blood.
• Fever or chills, and urine that is cloudy or foul-smelling.

What is the treatment for kidney stones?

Most often, non-surgical approaches are taken when treating small kidney stones, with most of the focus on managing the child’s pain. Children waiting to pass stones at home should urinate into a coffee filter, loose tea filter or urine strainer, so that the stone can be collected and brought into the urology center to be analyzed under a microscope.

Today, minimally invasive treatment is used for almost all large or obstructing kidney stones. Although the majority of smaller stones will pass without a medical procedure, large stones that are unlikely to pass through on their own must be broken up by a process known as lithotripsy. Extracorporeal lithotripsy, also called ESWL, uses shock waves from an outside source to break the stones into smaller fragments that can be swept away in urine. This is the most common procedure used to break up large stones.

Sometimes a stone will form or get stuck in the bladder. If this happens, then the child may need a cystoscopy. With this procedure, a small telescope is passed up the urethra to the bladder. The stone is then removed by passing a basket-like device up the scope to retrieve it. This is often done when stones are larger or have irregular shape and is done under general anesthesia.

How can kidney stones be prevented?

After the cause of a child’s stone is identified a specific prevention plan will be put together for your child. This plan may include changes to foods and drinks in the child’s current diet.

The best way to prevent kidney stones is to maintain an appropriate weight and drink the right amount of water each day. The occurrence (or recurrence) of stones is more common for those who do not drink enough water. Learn more about how much water children should drink each day.