What are kidney stones?
Usually, your kidneys remove waste from your blood to make urine (pee). When there is too much waste in your blood and your body is not producing enough urine, crystals begin to form in your kidneys. These crystals attract other wastes and chemicals to form a solid object (a kidney stone) that will get larger unless it is passed out of your body in your urine.
Kidney stones can be as small as a grain of sand or as large as a golf ball.
What causes kidney stones?
Anyone can get a kidney stone, but some people are more likely than others to get them. Men get kidney stones more often than women. Kidney stones are also more common in non-Hispanic white people than in people of other ethnicities. You may also be more likely to get a kidney stone if you:
- Have had kidney stones before
- Have someone in your family with kidney stones
- Do not drink enough water
- Eat a lot of protein, sodium (salt), or sugar
- Are overweight
- Have had a surgery on your intestines
- Have polycystic kidney disease
- Have a health problem that causes your urine (pee) to contain high levels of cystine, oxalate, uric acid or calcium
- Have a health problem that causes swelling or damage in your digestive system or your joints
- Take certain medicines, such as diuretics (water pills) or calcium-based antacids
What are the symptoms of kidney stones?
If you have a small kidney stone, it may travel out of your body through your urine (called passing a kidney stone). You may not have any symptoms and may never know that you had a kidney stone.
If you have a larger kidney stone, it may get stuck in your urinary tract and block urine from getting through. You may notice symptoms, including:
- Pain while urinating (peeing)
- Blood in your urine (pee)
- Sharp pain in your back or lower belly area
- Stomachache that does not go away
- Feeling sick to your stomach or throwing up
- A fever and chills
- Urine (pee) that smells bad or looks cloudy
You may feel a lot of pain when you pass a kidney stone or if a large kidney stone blocks the flow of your urine.
If you are having any of these symptoms, contact your doctor.
How can I prevent kidney stones?
Here are a few steps you can take to prevent kidney stones:
- Drink enough fluids every day. Eight to twelve cups of fluid per day is enough for most people. If you have kidney disease and need to limit fluids, ask your doctor how much fluid you should have each day.
- Limit your sodium (salt) and animal protein such as meat and eggs. If your doctor can find out what your kidney stone is made of, they may give you a specific eating plan to help prevent future kidney stones.
- Take all of your prescription medicines as your doctor tells you to treat health problems that may make kidney stones more likely for you.
Never start or stop any new medicines or an eating plan without talking to your doctor.
How will I know if I have a kidney stone?
To find out the size and type of kidney stone you have, your doctor may do tests, including:
- Blood tests to show if there is too much calcium or uric acid in your blood
- Urine (pee) tests to show the type of wastes that are in your urine. For this test, your doctor may ask you to collect your urine over two days.
- Imaging tests, such as an ultrasound, CT scan or X-ray, to show kidney stones in your urinary tract
If you get kidney stones often, your doctor may ask you to urinate through a strainer to catch stones that you pass. Your doctor will then find out what they are made of to decide what is causing your kidney stones and how to prevent them.
How do doctors treat kidney stones?
The treatment for a kidney stone depends on:
- The size of the stone
- The type of stone
- If the stone is causing you pain
- If the stone is blocking your urinary tract
If your kidney stone is small, your doctor may have you take pain medicine and drink fluids to help push the stone through your urinary tract and out through your urine (pee).
If your kidney stone is large or if it is blocking your urinary tract, a different treatment may be needed. Treatment options include:
Lithotripsy treatment uses shock waves to break up the kidney stone into small pieces. After the treatment, the small pieces of the kidney stone will pass through your urinary tract and out through your urine. This treatment usually takes about one hour and may be done under general anesthesia, which means you will be asleep and unable to feel the procedure.
During a ureteroscopy, a doctor inserts a long tube-like tool into your ureter to take out the stone (if it is small) or break the stone into small pieces (using a laser if it is large) to pass through your urinary tract and out through your urine.
In rare cases, surgery is needed to remove a kidney stone. During the surgery, a doctor will insert a tube into your kidney to remove the stone. You will need to be in the hospital for two to three days to recover from this treatment
What are the types of kidney stones?
There are four types of kidney stones:
Calcium stones are the most common type of kidney stones. They form when calcium mixes with oxalate (a natural chemical found in most food) in your urine. These form when you are not getting enough fluids or calcium.
Uric stones are also a common type of kidney stone. High levels of a natural chemical called purine (in some meats and shellfish) in your body can cause a high level of a chemical called urate that can create these kidney stones. This type of kidney stone tends to run in families.
Struvite stones are less common than calcium and uric stones. Struvite stones can happen when bacteria from upper urinary tract infections (UTIs) get into your urinary tract.
Cystine stones are caused by a rare condition called cystinuria that is passed down in families. Cystinuria causes a natural chemical called cystine to leak into your urine. When there is too much cystine in your urine, kidney stones can form. These stones can get stuck in your kidneys, bladder or anywhere in your urinary tract. Most people with cystinuria will get many stones in their life. It is a lifelong condition that can be treated but not cured.