Urinary Incontinence

The compression of pelvic nerves and the stretching of the pelvic floor during vaginal delivery can result in neuromuscular damage. The function of the urethral sphincter may thus be compromised, contributing to the higher prevalence of stress urinary incontinence (SUI; loss of urine with stress maneuvers such as coughing, laughing, or sneezing) in women who have had many children, compared with women who have had none. Aging and/or diseases that affect the peripheral, autonomic, or central nervous system control of continence, can also result in urinary incontinence. Some older men and women lose cerebral cortical control for unclear reasons, resulting in an unstable, ‘‘overactive’’ bladder (so called idiopathic detrusor instability). This condition is manifested by urinary urgency (e.g., the sudden need to void) and urgency incontinence.

Diseases affecting the cerebral cortex, such as strokes and multiple sclerosis, may result in bladder overactivity (detrusor hyperreflexia) because of central nervous system involvement. Diseases that affect the midbrain or spinal cord, such as multiple sclerosis and spinal cord injury, interfere with the coordination of sphincter relaxation during voiding. This loss of synchronization of sphincter relaxation with bladder contraction is termed detrusor-urethral dyssynergia, and results in voiding that is uncoordinated and incomplete.

Interference of bladder sensory nerves due to long-standing diabetes or physical injury to the pelvic motor nerves may result in loss of bladder sensation or contractility of the detrusor muscle. This causes the bladder to contract poorly, resulting in incomplete emptying of the bladder and urine retention. Obstruction to the flow of urine from the bladder commonly occurs in elderly men due to prostatic gland enlargement. Narrowing of the urethra (urethral stricture) in men or women can also cause physical obstruction to urine flow, resulting in urinary retention and overflow incontinence. In older men, radical surgery for prostate cancer can interfere with sphincteric urinary control. However, urgency urinary incontinence is the most common type of incontinence in men, with lower urinary tract symptoms, functional and cognitive impairment, prostatectomy and urological conditions as recognized risk factors. This condition can be a symptom of an enlarged prostate.

In developing countries where health care resources are scarce, maternal birth injury due to obstructed labor is not uncommon. Injury to the urethra, bladder, and vagina can result in the formation of fistula, which are abnormal tracts that connect the bladder or urethra directly with the vagina, resulting in constant uncontrolled urine loss. For women affected, this is a devastating complication.

Post-menopausal estrogen decline may cause changes in the urogenital tract, especially shrinkage (atrophy) of supporting tissue. With age, pelvic muscle function is reduced and pelvic tissues lose elasticity. Obesity in older women increases abdominal pressure and may be a contributing factor to SUI.