Kidney stones are pieces of a stone or crystal-like material. These stones form inside the kidneys or other parts of the urinary tract. The kidneys remove waste from the body and balance the water and electrolyte content in the blood by filtering salt and water.
There are several types of kidney stones:
- Calcium oxalate
- Calcium phosphate
- Uric acid
The cause of your kidney stone may depend on the type of stone that you have. Calcium stones are the most common type.
- Calcium oxalate or phosphorus stones — These kidney stones form when the concentration of calcium or other minerals in the urine becomes too high.
- Struvite stones — These stones develop as a result of a urinary tract infection. The stones are composed of ammonium, magnesium and phosphate salts.
- Uric acid stones — These stones form when urine is acidic. This may also occur in people with gout or undergoing chemotherapy.
- Cystine stones — These stones form because of a rare genetic disorder that causes the kidneys to accumulate excessive amounts of cystine, one of the amino acids that make up proteins.
Are You at Risk?
Common factors that increase your risk of kidney stones include:
- White adult male under 50 years old
- Personal history of kidney stones
- Family history of kidney stones
Other factors that increase your risk of kidney stones include:
Calcium oxalate or phosphorus stones:
- Excess dietary sodium and oxalate. Oxalate can be found in green, leafy vegetables, chocolate, nuts or tea.
- Low fluid intake, especially during warmer weather, which can lead to dehydration
- Overactive parathyroid gland
- Chronic bowel disorders such as Crohn’s disease or ulcerative colitis
- Some diuretics
- Calcium-based antacids
- History of urinary infection
- More common in women
Uric acid stones:
- Excess dietary red meat or poultry
In many people, kidney stones do not cause symptoms and pass during urination. Other people may have symptoms that include:
- Sharp, stabbing pain in the mid-back that may occur every few minutes and last from 20 minutes to one hour
- Pain in the lower abdomen, groin or genital areas
- Nausea and vomiting
- Blood in the urine
- Frequent urge to urinate
- Burning pain during urination
Your doctor may recommend tests to confirm a diagnosis and rule out other conditions. These may include:
- Urinalysis, 24-hour urine or urine culture
- Blood tests
- Spiral CT scan
- Intravenous pyelogram (IVP)
Treatment depends on the size and location of the kidney stone. Treatment may include one or more of the following.
For small kidney stones, drinking at least two or three quarts of water a day helps the body pass the stones during urination. Your doctor may provide a special cup to catch the stone when it passes so it can be sent for analysis. You may require hospitalization to receive IV fluids if you're having a hard time keeping fluids down.
Your doctor may prescribe you medications to help you pass your kidney stones during urination. He or she may also recommend that you take pain medication.
You may need surgery if the stones are:
- Very large or growing larger
- Causing bleeding or damage to the kidney
- Causing infection
- Blocking the flow of urine
- Unable to pass on its own
Ureteroscopy uses a small camera to locate the stones in your ureter or kidney. Once found, a small basket captures and removes the stones. Larger stones can be broken up into small pieces with a laser.
Percutaneous nephrolithotomy (PNL)
PNL treats large stones in the kidney. Your doctor makes a small incision in your lower back and passes a nephroscope through a tube to make your kidney stones visible. Your doctor breaks the stones into smaller pieces and removes them. A temporary drain may be left in the incision site.
Lithotomy is an open surgery that removes stones. This is rarely used because of the less invasive options available.
Extracorporeal Shock Wave Lithotripsy (ESWL)
Extracorporeal shock wave lithotripsy (ESWL) uses a device called a lithotripter that your doctor applies to the skin. The lithotripter sends shock waves into your body to break up the larger stones for easier passage during urination.
You're more likely to form a kidney stone once you've already had one. Steps to prevent this condition include:
- Drink plenty of fluids, especially water.
- Depending on the type of stone you have, you may need to avoid certain food or drinks.
- Depending on what type of stone you have, your doctor may prescribe certain medication to keep stones from forming again.
Content was created using EBSCO’s Health Library. Edits to original content made by Rector and Visitors of the University of Virginia. This information is not a substitute for professional medical advice.