Kidney stones are stone-like lumps that can develop in one or both of the kidneys. The medical name for stones in the kidneys is nephrolithiasis. If the stones cause severe pain, it is known as renal colic.
The kidneys
The kidneys are two bean-shaped organs that are roughly four inches in length. They are located towards the back of the abdomen (stomach ) on either side of the spine.
The kidneys remove waste products from the blood and transfer them into the ureter, along with excess fluids. The ureter is the tube that attaches each kidney to the bladder. From there, the waste products and excess fluid are disposed of as urine. The clean blood is then transferred back into the body.
Kidney stones
The waste products in the kidneys can occasionally form crystals that collect around the inside of the kidney. Over time, the crystals may build up to form a hard stone-like lump. This is a kidney stone.
There are four main types of kidney stone. See Kidney stones - symptoms for more information about the different types of kidney stones.
How common are kidney stones?
Kidney stones are quite common and usually affect people who are between 30-60 years of age. They affect men more than women. It is estimated that renal colic (severe pain caused by a kidney stone) affects about 10-20% of men, and 3-5% of women.
Outlook
After a kidney stone has formed, it will try to be passed in urine, and so will often travel through the urinary system. The urinary system produces, stores, and removes urine. The urinary system is made up of the kidneys, the ureters, the bladder and the urethra (the tube that carries urine from the bladder to the outside of the body) .
While small stones may be passed out in the urine, it is fairly common for a stone to block part of the urinary system, such as the ureter or the urethra. If this happens, it can cause severe pain in the abdomen or groin. A blockage in the urinary system can also lead to:
- infection
- kidney damage
- kidney failure
There are a number of procedures to remove, or break down, larger kidney stones. Around half of people who have had kidney stones will experience them again within the next 10 years .
Kidney
Kidneys are a pair of bean-shaped organs located at the back of the abdomen. They remove waste and extra fluid from the blood and pass them out of the body as urine.
Abdomen
The abdomen is the part of the body between the chest and the hips.
Spine
The spine supports the skeleton, and surrounds and protects the delicate spinal cord and nerves. It is made up of 33 bones called the vertebrae.
Blood
Blood supplies oxygen to the body and removes carbon dioxide. It is pumped around the body by the heart.
Bladder
The bladder is a small organ near the pelvis that holds urine until it's ready to be passed from the body.
Urethra
The urethra is a tube that carries urine from the bladder to the outside of the body.
Pain
Pain is an unpleasant physical or emotional feeling that your body produces as a warning that it's been damaged.
Groin
The groin is the area at the front of the body where the thigh meets the abdomen.
Last updated: 11 November 2011
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