Despite having a full bladder it is sometimes difficult to pass urine (stranguary) because of anxiety, stress or the location in which it is being attempted. A number of diseases almost invariably affecting men may also be responsible for difficulty urinating.
The prostate gland at the base of the penis is responsible for producing some of the fluid (semen) which is ejaculated during sex. With increasing age this tends to enlarge, putting pressure on the urethra (urine tube from bladder to the outside), which passes through the middle of the gland, making it more difficult to pass urine. In extreme cases it may become impossible to pass any urine and the bladder will increase to an enormous size causing considerable pain.
Cancer of the prostate is a common condition of elderly men, but it progresses very slowly in most cases and its presence may not be noticed until the enlarging cancer puts pressure on the urethra to make passing urine difficult. An aching pain at the front of the pelvis is the other possible symptom.
Other causes include:
- prostatitis (a bacterial infection of the prostate gland),
- urethritis (infection of the urethra),
- an injury to the urethra,
- an inserted foreign body,
- a stone, polyp, tumour, cancer or blood clot in the bladder that may block the opening of the bladder into the urethra.
Damage to the opening of the bladder into the urethra may occur in women who have repeated bladder infections resulting in a bladder outlet obstruction.
Rarely the nerve supply to the bladder may be damaged by an injury to the lower back or pelvis, making bladder emptying difficult or impossible.