The only two functions of the bladder are to store urine and to expel urine in a coordinated fashion under appropriate circumstances. The bladder needs to be of adequate capacity and compliance in order to store urine. The tone within the bladder neck and sphincter (valve) prevents urine from leaking from the bladder. During voiding, the bladder muscle contracts while the sphincter relaxes in a coordinated fashion.
Incontinence can be classified according to the mechanism causing the leakage of urine or according to the type of symptoms.
The main types of urinary incontinence are:
- Stress urinary incontinence
- Urge incontinence
- Overflow incontinence
- Total incontinence
Urge incontinence is the leakage of urine associated with a great desire to urinate that cannot be suppressed. It's invariably associated with symptoms of urgency and frequency. The bladder is incapable of storing adequate amounts of urine, because it's either too small or unstable. There are many different causes of urge incontinence.
Overflow incontinence is associated with chronic retention of urine. The bladder is permanently full and distended with urine. The kidneys continue to produce urine and the excess spills out of the urethra, much like a dam that's overflowing. Overflow incontinence is associated with a poor stream and difficulty passing urine. Chronic retention is either due to bladder-outlet obstruction or bladder-muscle dysfunction. Bladder-outlet obstruction is relatively common in elderly males and rare in females.
Total incontinence is the continuous leakage of all the urine. It's most often due to a vesicovaginal fistula, which is an abnormal communication between the bladder and the vagina.
Urinary incontinence affects about 8% of females and 3% of males. It's more common in the elderly, but shouldn't be regarded as normal at any age. There's no single treatment for urinary incontinence. The treatment options will depend on the type and severity of the incontinence.
Most people with urinary incontinence can be cured or improved.