The most common cause of bladder stones is an inability to empty your bladder fully of urine.
Urine is produced by your kidneys. It is made up of water mixed with waste products that the kidneys remove from your blood. One of the waste products is urea, which is a chemical compound made up of nitrogen and carbon.
If urine is allowed to stay in your bladder, the chemicals inside urea will begin to stick together and form crystals. Over time, the crystals will start to harden (calcify) and form bladder stones.
Some common reasons why people are unable to empty their bladder fully are described below.
The prostate is a small gland that is only found in men, and is located behind the pelvis. The prostate is found between the penis and the bladder, and surrounds the urethra (the tube that carries urine from the bladder to the penis).
The main function of the prostate is to help with the production of semen. In many men, the prostate becomes enlarged as they grow older. Prostate enlargement is also known as benign prostate hyperplasia.
The enlarged prostate places pressure on the urethra, interrupting the normal flow of urine, which remains in the bladder.
Neurogenic bladder is a condition where the nerves that the brain uses to control the bladder are damaged, which means that a person is unable to empty their bladder fully.
A neurogenic bladder can develop as a result of spinal cord damage, stroke or neurological conditions (conditions that affect the nervous system), such as spina bifida.
Most people with a neurogenic bladder require a catheter to empty their bladder. A catheter is a tube that is inserted into the urethra and moved up into the bladder. The urine is drained out of the bladder through the catheter.
In some cases, it is not possible for a person to drain their bladder fully using a catheter. This can lead to bladder stones forming inside.
A cystocele is a condition that affects women and develops when the wall of the bladder becomes weakened and begins to drop down on to the vagina. This can affect the normal flow of urine out of the bladder.
A cystocele can develop during a period of excessive straining, such as childbirth, chronic constipation or heavy lifting.
Bladder diverticula are pouches that develop in the wall of the bladder. If the diverticula grow to a certain size, it can become difficult for a person to empty their bladder fully.
Bladder diverticula can be present at birth or develop as a complication of infection or prostate enlargement.
Other causes of bladder stones
Other, less common causes of bladder stones include:
- a diet that is high in fat, sugar or salt
- prolonged dehydration
- vitamin A and/or vitamin B deficiency
All three of these factors can alter the chemical composition of urine, making the formation of bladder stones more likely.
However, these risk factors only tend to affect people who are living in the developing world, and they are uncommon causes of bladder stones in Ireland.