Kidney stones are stone-like lumps that can develop in one or both of the kidneys. Kidney stones are quite common. In the UK they affect around three in 20 men and one in 20 women.
How do the kidneys work?
The kidneys are two bean-shaped organs that are roughly four inches in length and located towards the back of the abdomen, on either side of the spine.
Kidneys work by removing waste products from the blood. The waste products are transferred into the ureter (the tube that attaches each kidney to the bladder) along with excess fluids, and from there they are disposed of as urine. The clean blood is then transferred back into the body.
What is a kidney stone?
There are four main types of kidney stone:
- Calcium stones are made from calcium and phosphate, or calcium and oxalate.
- Struvite stones contain magnesium and ammonia, and are often horn-shaped and quite large.
- Uric acid stones are usually smooth, brown and softer than other forms of kidney stones.
- Cystine stones are often yellow and resemble crystals rather than stones.
Kidney stones come in a variety of shapes, sizes and colours. Some resemble grains of sand while, in rare cases, others can grow to the size of a golf ball.
How does a kidney stone form?
The waste products are usually dissolved in the fluids that form urine but, occasionally, they can form crystals that collect around the inside of the kidney. The crystals may gather over time to form a hard stone-like lump. This is a kidney stone.
After a kidney stone has formed, it will often travel through the urinary system as it tries to be passed in urine. However, it is fairly common for a stone to block part of the urinary system, such as the ureter or the urethra (the tube that carries urine from the bladder to the outside of the body). If this happens, you may experience severe pain in your abdomen or groin. A blockage in the urinary system can also lead to infection, kidney damage or, sometimes, kidney failure.
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.
