Bladder stones

The bladder is a muscular container that stores urine until it leaves your body via urination. Sometimes, the waste products in urine can form into crystals in the bladder. These are bladder stones.

Problems can arise when these crystals become too large to be flushed out of the body during urination, particularly if they are trapped in the narrow urethra (the tube that carries urine from the bladder to the outside of the body).

A tiny stone in the urethra can cause great pain and lead to difficulty passing urine, whilst a much larger stone in the bladder may go undetected for some time. The majority of bladder stones are formed of calcium, which comes from too much salt in the urine.

Bladder stones are a common problem in men, and are most common in those over 45. If left untreated, bladder stones can irritate the muscles of the bladder wall and lead to incontinence.

Bladder stones are very common - a change in the acidity of the urine can be enough to make a stone form. A change in acidity is often triggered by an incorrect diet or by not drinking enough fluids.

Bladder stones can also develop if urine stagnates in your bladder as a result of a 'blind pouch'. This is a structural abnormality of the bladder that prevents urine from completely draining away. It is sometimes caused by an enlarged prostate gland pressing on the bladder, that creates a portion of the bladder from which urine cannot entirely empty.

Those who have a history of urinary tract infection are more likely to develop bladder stones, as repeated infections can encourage stones to grow. Medical conditions such as gout, which affect the level of waste products in urine, can also cause bladder stones to form.

However, bladder stones can also form in healthy individuals for no apparent reason.

Most bladder stones are formed within the bladder, but some may initially form in the kidneys and then travel through the urinary system to the bladder.

A bladder stone may go unnoticed until it irritates the soft lining of the bladder wall. You may then see blood in the urine, particularly towards the end of urination.

Bladder stones may also cause:

- pain when passing urine,
- a frequent and sometimes urgent need to empty the bladder, and
- blood in the urine.
If a stone gets stuck at the entrance to the urethra, it may block the emptying of the bladder, or the jet of urine may suddenly stop halfway through urination. This can cause pain in the back or hip, the tip of the penis or scrotum in men, or the perineum (area between the vagina and the anus) in women. The pain may be dull or sharp and is often made worse by sudden movements and exercise.

If your GP suspects you have a bladder stone, you should be refered to hospital for tests. A variety of tests can be used to identify bladder stones, including an ultrasound scan or an intravenous urogram. In an intravenous urogram a dye is injected into a vein, which then travels out of the body through the urinary system. The dye shows up clearly on an X-ray, allowing any bladder stones and their location to be identified.

Abnormalities in the bladder can also be identified with a cystoscopy. In this procedure a thin, hollow viewing tube is inserted into the urethra in order to view the inside of the bladder.

Blood and urine samples may also be tested to identify any underlying medical conditions that may be causing bladder stones.

Bladder stones usually need to be broken down in order to flush them out of the body. This may be done during a cystoscopy, or by using a form of sound energy known as lithotripsy.

During a cystoscopy, an instrument can be passed into the bladder through the cystoscope tube that can break the stone down using laser or ultrasound energy. Alternatively, if the stone is small, an instrument that looks like a tiny grabber can be passed through the tube. The stone can then be held and extracted.

Lithotripsy is usually carried out in hospital, and uses high-energy sound waves applied from outside the body to break bladder stones down into smaller fragments. These fragments are then small enough to be emptied from the bladder with the urine. Painkillers are sometimes given before the procedure as it can cause some discomfort. Your abdomen is likely to feel tender after treatment and you may have blood in your urine for a short time afterwards, but serious complications are uncommon.

Lithotripsy prevents the need for surgery, which is only necessary if the stones are very large.

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Drinking large amounts of fluids - eight to ten glasses of water a day - can keep you properly hydrated and help prevent stones from forming.

Bladder stones often recur - about 60% of those who have a bladder stone will develop another stone within seven years.

Measures to prevent the formation of new stones depend on what the previous stone was made of, but advice is usually based on changes to diet.

Most bladder stones contain a high percentage of calcium, so following a diet low in calcium can help. If the stone contained uric acid, a diet low in meat, fish and poultry is recommended. NHSDEC07