What are kidney stones?
Kidney stones are made of salts and minerals in the urine that stick together to form small "pebbles." They are usually painless while they remain in the kidney. But they can cause severe pain when small pieces leave the kidney and travel through the narrow tubes (ureters) to the bladder.
Symptoms of a kidney stone include severe pain in the flank, which is felt just below the rib cage and above the waist, usually on only one side of the back. The pain may spread to the lower abdomen, groin, and genital area. Other symptoms include blood in the urine (hematuria), painful or frequent urination (dysuria), and nausea and vomiting.
What causes them?
Kidney stones form when a change occurs in the normal balance of water, salts, minerals, and other things in urine. The most common cause is not drinking enough water. Some people are more likely to get kidney stones because of a medical condition, such as gout. They may also be an inherited disease.
How are they diagnosed?
Kidney stones may be diagnosed when you see your doctor or go to an emergency room with pain in your belly or side. Your doctor will ask questions about your symptoms and examine you. You may get imaging tests, such as a CT scan or ultrasound, to look at your kidneys and urinary tract.
How are kidney stones treated?
For most stones, your doctor will recommend home care, such as pain medicine and drinking plenty of water. You may get a medicine to help the stone pass. If it is too large to pass, you may need other treatment, such as one that uses shock waves to break the stone into small pieces.
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The most common cause of kidney stones is not drinking enough water. When you don't drink enough water, the salts, minerals, and other substances in the urine can stick together and form a stone. Most kidney stones form when the calcium levels in your urine change.
Kidney stones may also be an inherited disease. If other people in your family have had kidney stones, you may have them too.
In rare cases, a person forms kidney stones because the parathyroid glands produce too much of a hormone. This leads to higher calcium levels and may form kidney stones.
What Increases Your Risk
Several things can affect your risk for getting kidney stones. These include:
- How much fluid you drink. The most common cause of kidney stones is not drinking enough water.
- Your diet. Diets high in protein and sodium increase your risk for kidney stones. So do oxalate-rich foods, such as dark green vegetables. If you think that your diet may be a problem, a dietitian can help.
- Being overweight. This can cause both insulin resistance and increased calcium in the urine, which can increase your risk for kidney stones.
- Medicine. Some medicines can cause kidney stones to form.
Your age, gender, and whether you have a family history of kidney stones can also affect your risk. But these things are out of your control.
You can help prevent kidney stones by drinking plenty of water. Try to drink about 8 to 10 glasses a day. Eating less of certain foods may also help. Your doctor may give you medicine that helps prevent stones from forming.
If kidney stones stay in the kidney, they typically do not cause pain. When they travel out of the body through the tubes of the urinary tract, their movement may cause symptoms. These include:
- Sudden, severe pain that gets worse in waves. Stones may cause intense pain in the back, side, abdomen, groin, or genitals.
- Nausea and vomiting.
- Blood in the urine. This can occur with stones that stay in the kidney or with those that travel through a ureter.
- Frequent and painful urination. This may happen when the stone is in the ureter or after the stone has left the bladder and is in the urethra. Painful urination may occur when a urinary tract infection is also present.
If kidney stones are small enough, they may not cause symptoms.
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 ureters, which are the tubes that carry urine from the kidney to the bladder. This can cause pain and possibly block the urine from flowing. The pain can become severe. But it often goes away when the stone passes into the bladder. Medical treatment may be needed for larger stones.
When to Call
Call a doctor now if you have symptoms that suggest you have a kidney stone, such as:
- Severe pain in your side, belly, groin, or genitals. It may get worse in waves.
- Blood in your urine.
- Signs of a urinary tract infection, such as pain or burning when you urinate.
Call your doctor if you have been diagnosed with a kidney stone and have another problem, such as:
- Severe nausea or vomiting.
- Fever and chills.
- Severe pain in your side in the area of your kidney (flank pain).
Call your doctor to find out if you need an exam when you:
- Have been diagnosed with a kidney stone, and you need a stronger pain medicine.
- Pass a stone, even if there was little or no pain. Save the stone, and ask your doctor if it should be tested.
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:
- Can control your pain with medicine.
- Know how to look for and collect kidney stones you pass.
- Don't have signs of infection, such as fever and chills.
- Are able to drink plenty of fluids.
- Don't have severe nausea or vomiting.
Exams and Tests
Kidney stones may be diagnosed when you see your doctor or go to an emergency room with pain in your belly or side. Your doctor will ask about your symptoms and examine you.
Your doctor may do tests to help diagnose kidney stones and see where they're located. Tests include:
- A noncontrast spiral CT scan. This is a special type of CT scan that moves in a circle.
- An ultrasound exam (ultrasonogram). This uses reflected sound waves to examine your urinary tract.
- An intravenous pyelogram (IVP). This is an X-ray test that shows pictures of the urinary tract and kidney stones.
- A retrograde pyelogram. This uses a dye to check whether a kidney stone or something else is blocking your urinary tract.
- Urinalysis and urine cultures. These test your urine.
- An abdominal X-ray (KUB). This creates a picture of the kidneys, the bladder, and the tubes that connect the kidneys to the bladder (ureters).
If your doctor thinks the stone can pass on its own, you may be told to take medicine, such as nonsteroidal anti-inflammatory drugs (NSAIDs). The doctor may also suggest drinking enough fluids. You'll need to keep drinking water and other fluids when you are passing a kidney stone.
Your doctor may prescribe medicine (alpha blockers) to help your body pass the stone.
If your pain is too severe, you have an infection, or the stones are blocking the urinary tract, your doctor will probably suggest a medical procedure, such as lithotripsy. This uses shock waves to break a kidney stone into small pieces. Or the doctor will need to remove the stone or place a small, flexible plastic tube in the ureter. This is done to keep the ureter open while stones pass.
Drinking more fluids and taking pain medicine are often the only things you need to do when you pass a kidney stone.
- Drinking fluids.
When you are passing a kidney stone, drink plenty of water.
If you have kidney, heart, or liver disease and need to restrict fluids, talk with your doctor before drinking more fluids.
- Using 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 Advil and Motrin). Be safe with medicines. Read and follow all instructions on the label. Your doctor can prescribe stronger pain medicine if you need it.
Current as of: June 16, 2022
Author: Healthwise Staff
E. Gregory Thompson MD - Internal Medicine
Adam Husney MD - Family Medicine
Kathleen Romito MD - Family Medicine
Tushar J. Vachharajani MD, FASN, FACP - Nephrology