Illness & Conditions - Health Conditions
What are kidney stones?
Kidney stones are made of salts and minerals in the urine that stick together to form small "pebbles." They can be as small as grains of sand or as large as golf balls. They may stay in your kidneys or travel out of your body through the urinary tract . The urinary tract is the system that makes urine and carries it out of your body. It is made up of the kidneys, the tubes that connect the kidneys to the bladder (the ureters), the bladder, and the tube that leads from the bladder out of the body (the urethra).
When a stone travels through a ureter , it may cause no pain. Or it may cause great pain and other symptoms.
What causes kidney stones?
Kidney stones form when a change occurs in the normal balance of water, salts, minerals, and other things found in urine. The most common cause of kidney stones is not drinking enough water. Try to drink enough water, enough so that your urine is light yellow or clear like water (about 8 to 10 glasses a day). Some people are more likely to get kidney stones because of a medical condition, such as gout .
Kidney stones may also be an inherited disease. If other people in your family have had kidney stones, you may have them too.
What are the symptoms?
Kidney stones often cause no pain while they are in the kidneys, but they can cause sudden, severe pain as they travel from the kidneys to the bladder.
Call a doctor right away if you think you have kidney stones. Watch for severe pain in your side, belly, or groin or for urine that looks pink or red. You may also feel sick to your stomach (nausea) and may vomit.
How are kidney stones diagnosed?
You may first find out that you have kidney stones when you see your doctor or go to an emergency room with pain in your belly or side. Your doctor will ask you questions about your pain and lifestyle. He or she will examine you and may do imaging tests such as a CT scan or an ultrasound to look at your kidneys and urinary tract.
You may need more tests if you have more than one stone or have a family history of stones. To find out the cause of your kidney stones, your doctor may order a blood test and ask you to collect your urine for 24 hours. This can help your doctor find out if you are likely to have more stones in the future.
Kidney stones may not cause any pain. If this is the case, you may learn you have them when your doctor finds them during a test for another disease.
How are they treated?
For most stones, your doctor will suggest that you take care of yourself at home. You may need to take pain medicine. You'll need to drink enough water and other fluids so you don't get dehydrated . Your doctor may give you a medicine to help the stone pass.
If a stone is too large to pass on its own, or if it gets stuck in the urinary tract, you may need more treatment. About 1 or 2 out of every 10 kidney stones need more than home treatment. 1
The most common treatment is extracorporeal shock wave lithotripsy (ESWL). ESWL uses shock waves to break a kidney stone into small pieces. The bits can pass out of your body in your urine. Other times, a doctor will need to remove the stone or place a small flexible plastic tube (called a stent ) in the ureter to keep it open while stones pass.
How can you prevent kidney stones?
After you have had kidney stones, you are more likely to have them again. You can help prevent them by drinking plenty of water, enough so that your urine is light yellow or clear like water, about 8 to 10 glasses of water a day. You may have to eat less of certain foods. Your doctor may also give you medicine that helps prevent stones from forming.
Frequently Asked Questions
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Kidney stones may form when the normal balance of water, salts, minerals, and other substances found in urine changes. How this balance changes determines the type of kidney stone you have. Most kidney stones are calcium-type—they form when the calcium levels in your urine change.
Factors that change your urine balance include:
More commonly, kidney stones can run in families, as stones often occur in family members over several generations.
In rare cases, a person forms kidney stones because the parathyroid glands produce too much of a hormone, which leads to higher calcium levels and possibly calcium kidney stones.
Kidney stones form in the kidney. If they stay in the kidney, they typically do not cause pain. When they travel out of the body through the tubes of the urinary tract (including the ureters, which connect the kidney to the bladder, or the urethra, which leads outside the body), their movement may cause:
Conditions with similar symptoms include appendicitis, hernias, ectopic pregnancy, and prostatitis.
A kidney stone begins as a tiny piece of crystal in the kidney. When the urine leaves the kidney, it may carry the crystal out, or the crystal may stay in the kidney. If the crystal stays in the kidney, over time more small crystals join it and form a larger kidney stone.
Most stones leave the kidney and travel through the urinary tract when they are still small enough to pass easily out of the body. No treatment is needed for these stones.
Larger stones may become stuck in the tubes that carry urine from the kidney to the bladder (ureters). This can cause pain and possibly block the urine from flowing to the bladder and out of the body. The pain often becomes worse over 15 to 60 minutes until it is severe. The pain may ease when the stone no longer blocks the flow of urine, and it often goes away when the stone passes into the bladder. Medical treatment is often needed for larger stones.
Problems that may occur with kidney stones include:
Kidney stones are more serious for people who have a single kidney or an impaired immune system or have had a kidney transplant.
Stones in pregnant women
When stones occur during pregnancy, an obstetrician and urologist should determine whether you need treatment. Treatment will depend on your trimester of pregnancy.
What Increases Your Risk
Several risk factors (things that put you at risk) for kidney stones make it more likely that you will get them. Some of these things you can control, and others you cannot.
Risk factors you can control
Risk factors you can control include:
Risk factors you cannot control
Risk factors you can't control include:
When To Call a Doctor
Call a doctor immediately if you have symptoms that suggest you have a kidney stone, such as:
Call your doctor if you have been diagnosed with a kidney stone and have another problem, such as:
Call your doctor to find out if you need an exam when you:
Watchful waiting is a wait-and-see approach. If you get better on your own, you won't need medical treatment. If you get worse, you and your doctor will decide what to do next.
If you are passing a kidney stone under your doctor's advice, you may be able to pass the stone without medical treatment if you:
Who to see
If you need immediate help because of pain from kidney stones, you may see an emergency medicine specialist .
Health professionals who can diagnose and treat nonurgent kidney stones include:
To prepare for your appointment, see the topic Making the Most of Your Appointment.
Exams and Tests
Your first diagnosis of kidney stones often occurs when you see your doctor or go to an emergency room because you are in great pain. Your doctor or an emergency medicine specialist will ask you questions and examine you. After you pass a stone, your doctor may give you another exam to find out whether you are likely to get kidney stones again.
Tests to diagnose kidney stones
Your doctor may do one or more of the following tests to help diagnose kidney stones, see where they are located, and find out if they are causing or may cause damage to the urinary tract .
Tests to find out the type of stone
Determining the type of your kidney stone will help with treatment decisions and measures to prevent stones from forming again. Tests you may have include:
For small stones, most people don't need any treatment other than taking pain medicine and drinking enough fluids.
Treatment for your first stone
If your doctor thinks the stone can pass on its own, and if you feel you can deal with the pain, he or she may suggest home treatment, including:
Your doctor may prescribe medicine to help your body pass the stone. To learn more, see Medications.
If your pain is too severe, if the stones are blocking the urinary tract , or if you also have an infection, your doctor will probably suggest a medical procedure, such as lithotripsy, or surgery to deal with the stone. For more information, see Other Treatment and Surgery.
Preventing future stones
After you have had a kidney stone, you are more likely to have one again. Almost half of all people who have a stone will have more stones within 7 years unless they take preventive measures. 1
You may be able to prevent getting more kidney stones by drinking more fluids and making changes in your diet. Talk with your doctor or a dietitian if you need help with your diet. If you have risk factors (things that put you at risk) for having more stones, such as a family history of stones, your doctor may suggest medicines that help prevent stones from forming.
What to think about
You may need more treatment for your kidney stones if you have continuing problems and:
After you have had a kidney stone, you are more likely to have stones again. But you can take steps to help prevent them:
If you get more kidney stones despite drinking more fluids and making changes to your diet, your doctor may give you medicine to help dissolve your stones or to prevent new ones from forming. For more information, see Medications.
Home treatment—drinking more fluids and taking pain medicine—is often the only thing you need to do when passing a kidney stone.
When you are passing a kidney stone, you need to drink enough water to keep your urine light yellow or clear like water, about 8 to 10 glasses of water a day. If you have kidney, heart, or liver disease and are on fluid restrictions, talk with your doctor before drinking more fluids.
Use pain medicine
Medicine you can buy without a prescription, such as nonsteroidal anti-inflammatory drugs (NSAIDs), may relieve your pain. NSAIDs include aspirin and ibuprofen (such as Motrin and Advil). Your doctor can prescribe stronger pain medicine if needed.
Medicine to help pass stones
Medicine you can buy without a prescription, such as nonsteroidal anti-inflammatory drugs (NSAIDs), may relieve your pain while you pass a stone.
Your doctor may also prescribe medicine to help your body pass the stone. Alpha-blockers have been shown to help kidney stones pass more quickly with very few side effects. 3 Ask your doctor if these medicines can help you.
Medicine to prevent stones
Which medicine you take depends on the type of stones you have.
Uric acid stones
About 5 to 10 out of 100 kidney stones are made of uric acid, a waste product that normally exits the body in the urine. 1 To prevent these types of stones, you may take:
A very small number of stones are made of a chemical called cystine. 1 Medicines to prevent them include:
Some struvite stones ( staghorn calculi ) form because of frequent kidney infections . If you have a struvite stone, you will most likely need antibiotics to cure the infection and help prevent new stones from forming. You may need surgery to remove the stone. Urease inhibitors may be used to prevent struvite stones.
Surgery is rarely needed to treat kidney stones. Surgery is only needed when the kidney stone is very large, caused by an infection ( staghorn calculi ), blocking the flow of urine out of the kidney, or causing other problems like severe bleeding.
If your kidney stones were caused by a problem with your parathyroid gland , your doctor may suggest surgery to remove a parathyroid gland or glands (parathyroidectomy). This can help prevent future kidney stones.
Other treatments for kidney stones are much more common than surgery. You may need one of these treatments if your pain is very bad, your stone is blocking the urinary tract, or you have an infection. Your options include:
Whether these treatments will work for you will depend on the size of the stone, its location in the urinary tract, and your overall health.
Other Places To Get Help
Last Revised: April 28, 2011
Author: Healthwise Staff
Parmar MS (2004). Kidney stones. BMJ, 328(7453): 1420–1424.
Teichman JMH (2004). Acute renal colic from ureteral calculus. New England Journal of Medicine, 350(7): 684–693.
American Urological Association and European Association of Urology (2007, reaffirmed 2010). Ureteral Calculi: 2007 Guideline for the Management of Ureteral Calculi. Available online: http://www.auanet.org/content/guidelines-and-quality-care/clinical-guidelines.cfm?sub=uc.
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