The most common sudden cause is a urinary tract infection. However, urge incontinence without infection is the most common type of incontinence in older people and often has no clear cause. Common causes of urge incontinence in older people are overactivity of the bladder and neurologic disorders, such as stroke and dementia, which interfere with the brain's ability to inhibit the bladder. Urge incontinence becomes a particular problem when an illness or injury prevents a person from getting to the bathroom quickly. Stress incontinence is the uncontrolled loss of urine when coughing, straining, sneezing, lifting heavy objects, or performing any maneuver that suddenly increases pressure within the abdomen.
Stress incontinence is the most common type of incontinence in women.
It can be caused by weakness of the urinary sphincter. Sometimes the cause is changes in the urethra resulting from childbirth or pelvic surgery. In postmenopausal women, stress incontinence occurs because a lack of the hormone estrogen contributes to a weakened urethra, thus reducing the resistance to urine flow through this channel. Overflow incontinence is the uncontrolled leakage of small amounts of urine from a full bladder. The leakage occurs when the bladder becomes enlarged and insensitive because of chronic retention of urine.