Kidney stones are small, solid masses that can build up in a person's urinary
tract. They're hard, like little stones, but are actually crystals that form when
salts and minerals in urine (pee) become extra-concentrated. Over a few weeks or months,
these crystals can sometimes build up in the kidneys to become stones.
Kidney stones mostly happen to adults, though teens can get them.
Kidney stones range in size from a fraction of an inch to several inches. Very
small stones (like those that are less than ¼ inch or about 5 mm in size) usually
can pass through the urinary tract and out of the body on their own with little or
no pain. Larger stones can be quite painful, though. They may block the flow of urine
and cause other urinary tract problems. Luckily, it's rare for kidney stones to do
permanent damage, and doctors have lots of ways to treat them.
There are several kinds of kidney stones with many different causes. Because of
this, doctors treat them based on what kind they are — and how big. Some people
just need to drink a lot of water and take pain medicines to help a kidney stone pass
out the body naturally. Others might need surgery or another medical procedure.
How Do Kidney Stones Happen?
Our kidneys work like
a filter, removing extra fluids and waste products from the blood. These wastes leave
the body as urine.
Urine contains things like calcium, phosphate, oxalate, and uric acid. Usually,
these substances are very diluted so they flow through the urine easily. But
if urine becomes concentrated or something changes the level of a substance in the
urine, crystals might form. The crystals can become lodged in kidney tissue and grow
to become kidney stones.
Types of Kidney Stones
There are four major kinds of kidney stones:
Calcium stones. The most common kind of kidney stone, these develop
when calcium in the urine combines with other substances like oxalate or phosphate
to form crystals.
Uric acid stones. This type of stone forms when there's too much
uric acid in the pee. Uric acid can crystallize by itself or combine with calcium
to form a stone.
Struvite stones (also called staghorn calculi
because they look like a stag's antlers). These stones can grow rather large. They're
made of a mineral called struvite, which is a combination of ammonium, magnesium,
Cystine stones. This rare type of stone forms if someone has
too much of an amino acid called cystine in the urine.
What Causes Them?
Most teens who get kidney stones have a health condition that increases their risk
of developing them. Sometimes it's not clear what caused someone's kidney stones,
but doctors can still treat them.
Some types of kidney stones run in families. If a relative has had kidney stones,
you may be more likely to develop them at some point. People who have had kidney stones
in the past have a higher chance of getting them again.
Here are some reasons why people develop kidney stones:
Not drinking enough fluids can cause urine to become extra-concentrated. This increases
the chance of crystals forming.
An unhealthy diet and lifestyle. Drinking sugary, caffeinated,
or sports drinks and eating a diet high in sodium (salt) can increase the risk of
calcium stones. Obesity
also can make someone more likely to get them.
Urinary tract problems. Some people have a structural defect
in the urinary tract that blocks the flow of urine and creates an area where it sits
in a tiny pool. When this happens, crystal-forming substances may settle together
and form stones. Sometimes people (especially women) with kidney and urinary
tract infections (UTIs) can develop struvite stones.
Certain medicines. Some prescription and over-the-counter medicines
may cause kidney stones if taken in large doses.
Metabolic disorders. If the body has trouble breaking down and
using food, it can lead to concentrated levels of calcium, oxalate, or cystine in
Cystinuria. This genetic condition causes too much cystine to
pass from the kidneys into the urine, causing cystine stones to form.
Other medical conditions. A number of diseases and conditions
can increase the risk of kidney stones. These include gout, other diseases of the
kidneys, conditions that affect the thyroid or parathyroid gland, and some UTIs.
What Are the Symptoms?
Usually, people with kidney stones won't notice them until the stones move around
in the kidney or pass into the ureter. Small stones may move through the urinary tract
and out of the body with no problems. Larger stones, though, can block the urinary
tract and cause symptoms like these:
a sharp pain that starts in the side or back
pain that spreads to the lower belly and groin as stones move through the urinary
If a stone is too large to move, it might cause a blockage called hydronephrosis
(hye-drow-nuh-FRO-sis). Hydronephrosis is when one of the kidneys swells from a backup
of urine. Someone with hydronephrosis might feel side or back pain. Doctors can tell
if someone has it through imaging tests (like X-rays,
ultrasound, or CT scans).
If it's not treated, it can lead to long-term kidney damage.
If you feel pain in your side, see blood in your urine, or have other symptoms
of kidney stones, talk to your mom or dad and make an appointment to see a doctor
as soon as possible. If you are in pain and also feel nauseated, throw up, have fever
or chills, or have trouble peeing, go to an emergency clinic or hospital ER.
What Do Doctors Do?
Your doctor will examine you and ask about the symptoms and how long you've had
them. The doctor may also ask questions about your lifestyle, like what kinds of things
you eat and drink. The doctor will also be interested in your family medical history,
such as whether any relatives have had kidney stones or other diseases or conditions
that affect the kidneys or urinary tract.
If the doctor thinks you have a kidney stone, you'll probably have blood tests,
urine tests, or kidney
function tests. You also might undergo imaging tests (like an ultrasound or CT scan),
which can show a stone's exact size and location. This information helps doctors provide
the best treatment.
Treating Kidney Stones
Small stones usually work their way out of the body without much treatment. Large
stones may need to be treated with surgery or another procedure.
To help a small stone pass out of your body, the doctor will probably tell you
to drink plenty of water. Doctors may prescribe medicine for pain, but over-the-counter
medicines (like ibuprofen and acetaminophen) are usually enough to ease any pain from
small stones. Doctors may also prescribe medicine that helps move the stone if
it's in the ureter (the tube that connects that kidney to the bladder).
The doctor may ask you to pee through a strainer for a few days to collect kidney
stones as they come out your body. Doctors send the stones to a lab for testing to
find out which minerals make up the stones. Knowing this helps doctors decide the
best way to treat them.
Sometimes kidney stones require a hospital stay. If stones block the urinary tract
or cause severe pain or dehydration, patients need intravenous
(IV) fluids and pain medicines to stay hydrated and help the stone pass through
the urinary tract.
Large stones don't usually pass out of the body on their own. Doctors need to break
them up into smaller pieces, or remove them in one of several ways:
Using sound waves or shock waves to break kidney stones into small pieces. These
pieces can be passed out of the body in the urine (this process is called extracorporeal
shock wave lithotripsy).
Using a ureteroscope to find and break up kidney stones. A ureteroscope is a small
tube with a camera at the end. Doctors give the patient anesthesia,
then thread the tube into the urethra through to the bladder. The tube is then threaded
to the ureter and into the kidney until the stone is found. The ureteroscope has special
tools that can remove the stone from the urinary tract or break it into smaller pieces.
Using surgery to remove large stones. If someone has large stones in or near the
kidneys, doctors do surgery. The most common type of surgery is a procedure called
nephrolithotomy. After giving anesthesia, the surgeon makes a small cut in the patient's
back and inserts a tube called an endoscope into the kidney to remove or break up
the stone. People often stay in the hospital for a couple of days after kidney stone
Preventing Kidney Stones
It's not always possible to prevent some types of kidney stones. The best thing
you can do is drink enough water to avoid dehydration. If your urine is almost clear,
it's a sign that you're getting enough fluids. Another thing all teens can do is cut
back on salt and salty foods.
If you've had kidney stones in the past, your doctor will want you to drink plenty
of fluids (water is the best choice). You'll need about 8 cups (66 ounces or 2000
mL) a day and you'll need to eat a low-sodium diet. Ask your doctor if you need to
reduce the amount of animal protein (like meat or milk) that you consume. It can help
to talk with a doctor or dietitian about the best foods for you.
Doctors will want to monitor people who have had kidney stones to prevent new ones
from forming. So you may need to get a 24-hour urine collection test and blood tests.
Depending on the type of kidney stone someone has had, doctors can prescribe treatments
or medicines to reduce the levels of crystal-forming substances in the urine.
Kidney stones aren't usually a worry for most teens, though it's always a good
idea to eat healthy foods and drink enough fluids to avoid dehydration. If you play
sports, drinking water is your best best — sports drinks have a high concentration