Loss of urine can occur for a number of reasons that are related to the bladder (where urine is stored in the body) or the bladder sphincter (a thick muscle that controls the flow of urine out of the bladder).
Although aging itself doesn't cause incontinence, normal changes that occur in the urinary and genital systems as people age make this condition more common in the elderly.
For example, the bladder and the muscles that support it tend to sag with age, making it more difficult to store urine. Many medications taken by seniors for various medical conditions (e.g., high blood pressure, depression) can also increase bladder problems and lead to incontinence.
A common cause of temporary urinary incontinence is a urinary tract infection. Other causes of incontinence include severe constipation, delirium, depression, reduced mobility, and diabetes.
There are four types of urinary incontinence:
Stress incontinence: Urine will leak out in sudden spurts when someone coughs, sneezes, strains, or laughs. All these activities increase the pressure on the abdomen and bladder, causing urine to abruptly flow out. It's most commonly the result of weakened or stretched muscles that support the uterus and bladder. Childbirth via vaginal delivery, prolonged or difficult labour, previous pelvic surgery, being overweight, and having a family history of stress incontinence can all increase the risk of stress incontinence. As well, the loss of estrogen associated with menopause can lead to weakness of the pelvic muscle support and cause stress incontinence. Stress incontinence typically does not occur in men and may be seen only after some type of prostate surgery.
Overflow incontinence: This occurs when the bladder stores more urine than it can handle. It often affects elderly men who have enlarged prostate glands (called benign prostatic hyperplasia) or in women and men with a weak bladder muscle. In BPH, the large prostate squeezes or compresses the urethra (the tube that empties urine from the bladder) and prevents normal flow of urine. The urine then starts to collect in the bladder until there's so much excess that the bladder becomes distended (overstretched) and urine leaks out. Other conditions that can cause overflow incontinence include diabetic neuropathy and multiple sclerosis. Chronic untreated BPH can eventually lead to bladder muscle weakening.
Urge incontinence: Also referred to as "overactive bladder," this condition causes people to feel an urgent need to urinate due to muscle spasms in the bladder. It is the most common type of incontinence in older people. As a result of infection, stones, strokes, and dementia, the bladder spasms and causes urine loss.
Functional incontinence: This type of incontinence occurs when people have urge incontinence but are unable to get to the toilet because of conditions such as dementia, stroke, or immobility.
Some people may have mixed incontinence, which is a combination of the four types. The most common combination is urge and stress incontinence. Incontinence can either be temporary (e.g., caused by infections or medications) or persistent (e.g., due to a stroke or multiple sclerosis).