A kidney stone is a solid mass made up of tiny crystals. One or more stones can be in the kidney or ureter at the same time.
Kidney stones are common. Some types run in families. They often occur in premature infants.
There are different types of kidney stones. The cause of the problem depends on the type of stone.
Stones can form when urine contains too much of certain substances that form crystals. These crystals can develop into stones over weeks or months.
Calcium stones can also form from combining with phosphate or carbonate.
Other types of stones include:
The biggest risk factor for kidney stones is not drinking enough fluids. Kidney stones are more likely to occur if you make less than 1 liter of urine a day.
You may not have symptoms until the stones move down the tubes (ureters) through which urine empties into your bladder. When this happens, the stones can block the flow of urine out of the kidneys.
The main symptom is severe pain that starts suddenly and may go away suddenly:
Other symptoms can include:
The health care provider will perform a physical exam. The belly area (abdomen) or back might feel sore.
Tests that may be done include:
Stones or a blockage can be seen on:
Treatment depends on the type of stone and the severity of your symptoms.
Kidney stones that are small usually pass through your system on their own.
Some people with severe pain from kidney stones need to stay in the hospital. You may need to get fluids through a vein.
For some types of stones, your doctor may prescribe medicine to prevent stones from forming or help break down and remove the material that is causing the stone. These medicines can include:
Surgery is often needed if:
Today, most treatments are much less invasive than in the past.
Talk to your doctor about what treatment options may work for you.
Kidney stones are painful but most of the time can be removed from the body without causing lasting damage.
Kidney stones often come back. This occurs more often if the cause is not found and treated.
You are at risk for:
Call your health care provider if you have symptoms of a kidney stone.
If you have been diagnosed with blockage from a stone, passage must be confirmed either by capture in a strainer during urination or by follow-up x-ray.
If you have a history of stones:
Renal calculi; Nephrolithiasis; Stones - kidney
Curhan GC. Nephrolithiasis. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 128.
Finkelstein VA. Strategies for preventing calcium oxalate stones. CMAJ. 2006;174:1407-1409.
Ferrandino MN, Peitrow PK, Preminger GM. Evaluation and medical management of urinary lithiasis In: Wein AJ, ed. Campbell-Walsh Urology. 10th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 46.
Updated by: Scott Miller, MD, Urologist in private practice in Atlanta, Georgia. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.
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