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. They also balance the water and electrolyte content in the blood by filtering salt and water.
There are several types of kidney stones: Calcium oxalateCalcium phosphateStruviteUric acidCystine
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The cause of your kidney stone may be 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 or when minerals that prevent stone formation are too low.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 those who are on chemotherapy.Cystine stones—These stones form due to a rare genetic disorder that causes the kidneys to build up excess amounts of cystine. Cystine is one of the amino acids that make up proteins.
Factors that may increase your risk of kidney stones include: White adult male under 50 years oldPersonal history of kidney stonesFamily 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 dehydrationOveractive parathyroid gland
Chronic bowel disorders such as
ulcerative colitisSome diureticsCalcium-based antacids
Struvite stones: History of urinary infectionMore common in women
Uric acid stones: Excess dietary red meat or poultryGout
A rare genetic disorder increases the risk of cystine stones.
In many people, kidney stones do not cause symptoms and pass during urination. Other people may have symptoms, including: Sharp, stabbing pain in the mid-back that may occur every few minutes and last from 20 minutes to one hourPain in the lower abdomen, groin, or genital areasNausea and vomitingBlood in the urineFrequent urge to urinateBurning pain during urinationFever
You will be asked about your symptoms and medical history. A physical exam will be done.
Your bodily fluids may be tested. This can be done with:
Urine tests and cultures
Images may be taken of your kidneys and urinary system. This can be done with: X-raySpiral CT scanUltrasoundIntravenous 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. You may be given a special cup to catch the stone when it passes so it can be analyzed. If you are having a hard time keeping fluids down, you may need to be hospitalized to receive IV fluids.
You may be advised to take pain medication. You may also be prescribed medications that may help you pass your kidney stones during urination.
Surgery may be needed if the stones are: Very large or growing largerCausing bleeding or damage to the kidneyCausing infectionBlocking the flow of urineUnable to pass
Ureteroscopy uses a small camera to locate the stones located in the ureter or kidney. Once found, a small basket is used to capture and remove the stones. Larger stones can be broken up into small pieces with a laser.
PNL is used to treat large stones located in the kidney. A small incision is made in the lower back. A nephroscope is passed through a tube so the kidney stones can be seen. The stones are broken into smaller pieces and removed. A temporary drain may be left in the incision site.
Lithotomy is an open surgery used to remove stones. This is rarely used because of the less invasive options available.
ESWL uses a device called a lithotripter that is applied to the skin. The lithotripter sends shock waves into the body. The impact of the shock waves breaks up the larger stones so they can be passed during urination.
Once you have formed a kidney stone, you are more likely to form another. Here are some steps to prevent this condition: Drink plenty of fluids, especially water.Talk to your doctor about what diet is right for you. Depending on the type of stone you have, you may have to avoid certain food or drinks.Depending on what type of stone you have, certain medications may be prescribed to keep stones from forming again.
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Last reviewed March 2014 by Adrienne Carmack, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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