The bladder acts as a storage site for urine. To empty the bladder, its muscular wall contracts, pushing urine out through the neck of the bladder and into the urethra, the tube that carries urine out of the body. Powerful sphincter muscles control the dilation of the urethra, relaxing when it is time to void the bladder, but contracting to hold urine back at other times. The interplay of the bladder and sphincter muscles and the nerves that govern their contraction comprise bladder control. Urinary incontinence is the involuntary loss of urine from any cause.
Prevalence
Because of the embarrassing nature of the problem, the Merck Manual Online speculates that urinary incontinence is grossly underreported to doctors. Incontinence is more prevalent in the elderly, although it can strike at any age. The manual claims that 30 percent of elderly women and 15 percent of elderly men suffer from urinary incontinence. The National Institute of Diabetes and Digestive and Kidney Diseases says twice as many women experience urinary incontinence because of female-specific factors such as childbirth, hormonal changes and the anatomy of the female urinary tract.
Types
The Mayo Clinic outlines the various types of urinary incontinence. Stress incontinence, a common form in women, occurs when physical pressure on the bladder from factors such as coughing or exercising causes urine to leak. When the bladder fails to empty fully, urine can leak out involuntarily, causing overflow incontinence, rare in women but common in men, especially if they have prostate problems. Overactive bladder results from abnormal nerve communication with the bladder so that it contracts without warning. Abnormal nerve signaling can also cause urge incontinence, in which you suddenly feel an uncontrollable urge to urinate, even if you have no urine to excrete. When mental or physical impairments prevent you from reaching a bathroom in time, you have functional incontinence. Mixed incontinence encompasses symptoms of more than one of the above types.
Evaluation
Your doctor may have you keep a written record of your urination patterns for a few days to help pinpoint the cause of the problem. A urine culture can reveal infection or bladder stones, and a physical exam can diagnose a blockage or prolapse (protusion of the bladder into the vagina). Your doctor may measure the volume of urine left in your bladder immediately after you urinate, or use ultrasound or a special camera called a cytoscope to see inside the urethra and bladder. For men, the doctor will palpate (feel) the prostate.
Risk Factors
Pregnancy and vaginal delivery increase the risk of incontinence in women. Aging, associated with the decline in estrogen levels in women and prostate enlargement in men, increase the likelihood of incontinence. Lifestyle factors such as smoking, drinking alcohol or caffeine, and obesity all worsen incontinence, says the Mayo Clinic.
Treatment
The optimal treatment depends on the cause of incontinence and how aggressive the patient wants to be in pursuing a cure. Choices include changing lifestyle factors, behavioral training, medications and various types of surgery.
