Stress Urinary Incontinence Disease Profile

Synonyms: genuine stress incontinence, urethral hypermobility,

General description

The symptom includes involuntary loss of urine during physical exertion with increased intrabdominal pressure, such as with coughing, sneezing, laughing, exercise, lifting or sitting. The urine loss is usually not a large amount but the frequency with which it occurs may require wearing a pad constantly to avoid embarassment.

Is it common?

Urinary incontinence has been reported to affect 35% of American women over 50 years of age an almost 15% who have leakage on a daily basis. Approximately 60% of women with incontinence will have stress incontinence. Differentiating
features When lying down with legs apart, coughing produces a visible spurt of urine from the urethra. Standing up, with one leg on a stool and holding a paper towel over the perineum and coughing produces a wet stain on the paper towel.

A cotton-tipped stick lubricated with xylocaine gel is placed into the urethra up to, but not through the internal urethral sphincter (Q-tip test). With straining or coughing, the stick rises more than 30 degrees from it's resting angle. This demonstrates urethral hypermobility and differentiates genuine stress incontinence from an intrinsic urethral sphincteric insufficiency (ISD) without hypermobility.

Under urodynamic testing, the demonstration of the loss of urine when the intravesical pressure exceeds the maximum urethral pressure in the absence of a detrusor contraction.

On static urethral pressure profile, a maximum uretral pressure of greater than 20 cm of water rules out intrinsic urethral sphincteric insuficiency (ISD). On stress urethral pressure profile, a negative urethral differential pressure along the length of the urethra is confirmatory of stress incontinence.

Other features

Urgency can also be associated with stress incontinence and is not specific to urge incontinence. 75% of women with genuine stress incontinence will also report that they experience urge incontinence. 50% of women with pure detrusor instability report some of their incontinence is precipitated by stress. A cystometrogram showing no inhibited bladder contractions and a maximum cystometric capacity or more than 150 ccs (about 5 oz.) will rule out mixed urge and stress incontinence.

A post void residual urine of less than 200 ccs (about 7 oz.) helps to exclude an associated overflow incontinence.

Usually there is a history of vaginal childbirth.

Symptom onset is gradual over time.

Cause The theories:

Traditionally, genuine stress incontinence (GSI) has been viewed as an only an anatomic defect. It is thought that if the bladder and upper portion of the urethra are inside the abdominal cavity the a rise in the abdominal cavity should squeeze the bladder and upper urethra at the same time therefore preventing urine from escaping the bladder. If the upper urethra is not in the abdominal cavity because the muscles or fascia of the pelvic floor are stretched or loose, the urethra gets displaced from its normal intrapelvic location and descends outside of the abdominal cavity. As a result, as the pressure increases in the abdominal cavity during stress (like a cough) the upper part of the urethra is not closed off and the increased pressure in the bladder allows for leakage outside the body.
Recent studies have demonstrated a neurophysiological and histochemical evidence of denervation injury in subjects with GSI. Usually this is related to trauma from vaginal delivery of a child, repeated descent of the pelvic floor from chronic coughing, or straining from lifting or constipation.
There may be a connection with the pressure changes seen on urodynamics and lateral detachment of the anterior vaginal wall and endopelvic fascia from the levator ani muscles.

Unnecessary studies

Complex urodynamic studies are not necessary if there is not a history of other than mild urgency symptoms, the Q-tip test shows hypermobility, the postvoid residual urine is less than 200 ccs, the maximum bladder capacity is more than 150 ccs, there is no history of a previous bladder repair surgery and there is no history of any neurologic or spinal cord disease or trauma. Natural history
untreated If untreated, it usually slowly progresses over the years sometimes with a more rapid worsening right after menopause. Urinary loss episodes are more frequent urine which may be socially or hygenically unexceptable to the patient. Almost constant urine loss significantly irritates the perineal skin. Goals of
therapy (Rx) To stop or minimize the amount of involuntary urine loss 1st choice therapy Depends on the level of distress caused by the symptoms. All may be first line therapy

Use of pads or diapers as needed during other treatment.
Physical therapy to strengthen the external urethral sphincter such as: Kegel exercises, weighted vaginal cones, pelvic floor microstimulation therapy and bladder retraining therapy.
Vaginal pessary use which elevates the urethral vesical angle.
Medical management includes estrogen, phenylpropanolamine (PPA), combined estrogen and PPA, and discontinuance of any antihypertensive medications that are basically alpha receptor antagonists.
Surgical: Burch, MMK or needle-based retropubic urethropexy, sling procedures

Other therapies used See above

Treatments to avoid Avoid:

medications that may promote detrusor contractions such as: bethanechol, prostaglandins, excessive diuretic use or caffeine

agents that promote relaxation of the urethra include: alpha receptor blockers, phenoxybenzamine, phentolamine, prazosin, benzodiazapines (diazepam), progesterone, dantrolene

Reason for Rx choices

These treatments depend on the level of distress the loss of urine is causing, as well as the lifestyle modification needed to adjust to the symptoms. A trial of some form of physical therapy is used mostly for premenopausal women or women with milder symptoms. Bladder retraining is useful for all patients. Pessaries are useful for women who have decreased physical activity due to age or medical problems or who have to put off surgery for other reasons. Removal of medical therapy that causes or aggravates stree incontinence is useful in all patients.

References Thom D

Variation in estimates of urinary incontinence prevalence in the community: effects of differences in definition, population characteristics, and study type.

J Am Geriatr Soc 1998 Apr;46(4):473-480

NIH Consensus Development Panel, Rowe JW, chairperson, Urinary incontinence in adults.
JAMA 1989;261: 2685-90

Berghmans LC, Hendriks HJ, Bo K, Hay-Smith EJ, de Bie RA, van Waalwijk van Doorn ES
Conservative treatment of stress urinary incontinence in women: a systematic review of randomized clinical trials.
Br J Urol 1998 Aug;82(2):181-191

Videla FL, Wall LL
Stress incontinence diagnosed without multichannel urodynamic studies.
Obstet Gynecol 1998 Jun;91(6):965-968

Other resources National Association for Incontinence