Urinary Incontinence in Women
by Jay A. Naliboff, MD
What is urinary incontinence?
Urinary incontinence is the involuntary loss of urine. Leakage may or may not be associated with coughing, sneezing, or straining. It may occur during the day or during sleep and may or may not be associated with the urge to urinate.
How big a problem is it?
It is unknown how many women have urinary incontinence, but a walk down the aisle at the supermarket or pharmacy gives an idea of how much money is spent on adult incontinence products. It is a problem which many women suffer in silence either because they are embarrassed or because they feel that it is a normal consequence of aging.
Is there more than one type of urinary incontinence?
Actually, there are several types of urinary incontinence. One common variety is called urge incontinence. This occurs when the urge to void is followed rapidly by uncontrollable emptying of the bladder. It can be caused by bladder infection, by lack of estrogen, or by an abnormal sensitivity of the bladder nerves which causes the bladder to empty inappropriately. It can also result from sensitivity of the bladder lining to foods or drinks such as alcohol, caffeine, or acidic fruits and fruit juices (see list).
Closely related to urge incontinence is what is called an 'unstable bladder.' In this condition, certain stimuli such as cold or running water can cause an uncontrolled bladder contraction and leakage of large amounts of urine. Drinking excessive amounts of fluid can also cause urinary urgency and frequency as well as nocturia (getting up several times at night to void). Most of the liquid we drink ends up as urine. Women who drink continuously or who drink prior to going to bed often have frequency and nocturia.
Another type of incontinence is called overflow incontinence. Overflow incontinence occurs when the bladder doesn't empty completely and a large amount of urine remains after voiding. As more urine enters the already full bladder, it overflows and dribbles out continuously. This type of leakage can be associated with neurologic conditions such as multiple sclerosis or spinal cord injury and sometimes follows extensive pelvic surgery or radiation.
A third type of incontinence is due to an abnormal communication between the bladder and the vagina. This is called a urinary fistula and can occur after pelvic surgery such as hysterectomy, after radiation treatment for cervical cancer, and after difficult childbirth. The chief symptom of a fistula is continuous leakage of urine.
An additional reason to leak urine is called anatomic stress incontinence. This occurs when small to moderate amounts of urine are leaked when coughing, sneezing, exercising, and during other activities when there is increased pressure inside the abdomen. Normally when there is increased pressure on the bladder there is also increased pressure squeezing shut the bladder neck and urethra preventing loss of urine. If the bladder neck rotates down out of the abdomen with straining, there isn't as much squeeze applied to the bladder neck, and leakage of urine occurs. This is usually due to weakness of the tissue supporting the bladder due to childbirth and can be made worse by smoking, weight gain, and menopause.
A final cause of urinary incontinence is a lower than normal resting pressure inside the urethra. If the urethra is unable to stay closed, continuous leakage of urine will result. This condition can occur in women who have had previous surgery around the bladder or urethra who develop scar tissue holding the urethra open.
How do you decide what type of incontinence is present?
Often just taking a history will point toward the correct diagnosis. Women with urge incontinence give a history of urgency and frequency. Women with stress incontinence will only lose urine with coughing, straining, sneezing, and other activities that raise abdominal pressure. An unstable bladder may cause bed-wetting. Women with overflow incontinence may have a history of neurologic disease, diabetes, or spinal injury. Women with a scarred 'drainpipe' urethra will usually have a history of previous bladder or vaginal surgery.
The physical examination will show dropping of the bladder neck into the vagina with staining in women with stress incontinence but may be relatively normal in women with other types of leakage. If a fistula exists, thee may be a steady trickle of urine into the vagina.
A urine analysis and urine culture is always obtained to look for bladder infection.
The most common test done to determine the type of incontinence is called cystometrics. First the woman empties her bladder. Next a catheter is inserted into the bladder and the amount of urine remaining (called the residual) is measured. Women with overflow incontinence due to neurologic conditions or bladder nerve damage will have a high residual. Next, small amounts of water are infused into the bladder through the catheter and the pressure inside the bladder is measured. The volume of water required to feel the first urge to void is recorded. The amount of water that can be infused before the bladder contracts is measured. This is called the bladder capacity. Any uncontrolled bladder contractions are also noted. At the end of the cystometrogram, some of the water is drained from the bladder and the woman is asked to cough or strain, and any leakage of urine is recorded.
The table below shows the cystometric findings one would expect for the various types of incontinence.
|Overflow||Irritable Bladder||Stress Incontinence||Low Pressure Urethra|
|Uncontrolled Contractions||May have||Yes||No||No|
Some women who have had prior surgery or unusual leakage histories may require urodynamic evaluation done in a special laboratory with measurements of bladder and urethral pressures during voiding.
What can be done about the various types of incontinence?
Some forms of incontinence are best treated with medication. Estrogen replacement may restore enough tone to the bladder neck and urethra to stop the leaking. Bladder infections are treated with antibiotics. Leakage due to an irritable bladder often responds to tolerodine (Detrol TM), oxybutynin (Ditropan TM), or amitriptyline (Elavil TM). Avoiding certain foods and drinks and modifying fluid intake can also help.
Women with overflow incontinence can learn self-catheterization to keep bladder volume down.
Anatomic stress incontinence is best treated surgically. Many operations have been devised to keep the bladder neck from dropping during stress. The operation I perform is called a Burch procedure, which can be done either through an abdominal incision, or in some cases, with a laparoscope through a small belly button incision. Women with bladder fistulas also require surgery to close the defect.
Women with low urethral pressures are treated with either a 'sling' operation, in which a stripe of material is placed beneath the urethra to partially block it, or with collagen injections around the bladder neck.
Pine Tree Women's Care is a Program of Franklin Memorial Hospital.