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.
See also: Cystinuria
Kidney stones can form when urine contains too much of certain substances. These substances can create small crystals that become stones.
The biggest risk factor for kidney stones is dehydration.
Kidney stones may not produce symptoms until they begin to move down the tubes (ureters) through which urine empties into the bladder. When this happens, the stones can block the flow of urine out of the kidneys. This causes swelling of the kidney or kidneys, causing pain. The pain is usually severe.
Kidney stones are common. A person who has had kidney stones often gets them again in the future. Kidney stones often occur in premature infants.
Some types of stones tend to run in families. Certain kinds of stones can occur with bowel disease, ileal bypass for obesity, or renal tubule defects.
There are different types of kidney stones. The exact cause depends on the type of stone.
Other substances also can form stones.
The main symptom is severe pain that starts suddenly and may go away suddenly:
Other symptoms can include:
Pain can be severe enough to need narcotic pain relievers. The belly area (abdomen) or back might feel tender to the touch.
Tests for kidney stones include:
Stones or a blockage of the ureter can be seen on:
Tests may show high levels of calcium, oxylate, or uric acid in the urine or blood.
The goal of treatment is to relieve symptoms and prevent further symptoms. (Kidney stones that are small enough usually pass on their own.) Treatment varies depending on the type of stone and how severe the symptoms are. People with severe symptoms might need to be hospitalized.
When the stone passes, the urine should be strained and the stone saved and tested to determine the type.
Drink at least 6 - 8 glasses of water per day to produce a large amount of urine. Some people might need to get fluids through a vein (intravenous).
Pain relievers can help control the pain of passing the stones (renal colic). For severe pain, you may need to take narcotic pain killers or nonsteroidal anti-inflammatory drugs (NSAIDS) such as ibuprofen.
Depending on the type of stone, your doctor may prescribe medicine to decrease stone formation or help break down and remove the material that is causing the stone. Medications can include:
Surgery is usually needed if:
Today, most treatments are much less invasive than in the past.
Kidney stones are painful but usually can be removed from the body without causing permanent damage. They tend to return, especially if the cause is not found and treated.
Call your health care provider if you have symptoms of a kidney stone.
Also call if symptoms return, urination becomes painful, urine output decreases, or other new symptoms develop.
If you have a history of stones, drink plenty of fluids (6 - 8 glasses of water per day) to produce enough urine. Depending on the type of stone, you might need to take medications or other measures to prevent the stones from returning.
You may need to change your diet to prevent some types of stones from coming back.
Renal calculi; Nephrolithiasis; Stones - kidney