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Urinary incontinence is a significant problem, affecting millions of Americans. Patients may not report incontinence to their primary care providers due to embarrassment or misconceptions regarding treatment. Since incontinence is often treatable, it behooves the health care professional to identify patients who might benefit from treatment. Since the treatment of incontinence varies depending on the etiology, the aim of evaluation is to identify the etiology.
Urinary incontinence is generally the result of either bladder or urethral dysfunction (Table 1)
TABLE 1. Etiology Of Incontinence
There are other commonly used classifications of incontinence.
J. Christian Winters, MD (2011): Female Urology and Urinary Incontinence
Retrieved From: The American Urological Association Educational Review Manual in Urology: 3rd Edition Section: 2 Chapter: 12 Page: 344-344
Incontinence may also occur due to a non-urologic cause which is usually reversible when the underlying problem is treated (Table 2).
TABLE 2. Transient Causes of Incontinence (Diappers)
Resnick, N.M., Urinary Incontinence in the Elderly, Med. Gr. Rounds., 3: 281 – 290, 1984.
More uncommon causes of incontinence include urinary fistulae or ectopic ureteral orifices.
Bladder dysfunction causes urge or overflow incontinence. Urge incontinence occurs when the bladder pressure is sufficient to overcome the sphincter mechanism. Elevated bladder or detrusor pressure tends to open the bladder neck and urethra. An elevation in detrusor pressure may occur from intermittent bladder contractions (detrusor over activity) or because of an incremental rise in pressure with increased bladder volume (poor compliance). Detrusor over activity may be idiopathic or it may be associated with a neurologic disease (detrusor overactivity of neurogenic origin). Detrusor overactivity is common in the elderly and may be associated with bladder outlet obstruction. Poor bladder compliance results from loss of the visicoelastic features of the bladder or because of a change in neural-regulatory activity. The patient with urge incontinence may appreciate a sudden sensation to void but is then unable to suppress it fully. In severe cases the patient may not be aware of the sensation of needing to void until they are actually leaking. The amount of leakage in patients with urge incontinence is variable, depending on the patient's ability to suppress the contraction. Patients with urge incontinence will often have frequency and nocturia in addition to urgency and urge incontinence. They may also have nocturnal enuresis.
Overactive bladder is a newer term that describes patients with frequency and urgency with or without urge incontinence.
Overflow incontinence occurs at extreme bladder volumes or when the bladder volume reaches the limit of the bladder's viscoelastic properties. The loss of urine is driven by an elevation in detrusor pressure. Overflow incontinence is seen when there is incomplete bladder emptying caused either by obstruction or poor bladder contractility. Obstruction is rare in women but can result from severe pelvic prolapse or following surgery for stress incontinence. Patients with overflow incontinence will complain of constant dribbling and they may also describe extreme frequency.
Urethral related incontinence
Urethral related incontinence, or stress incontinence, occurs because of either urethral hypermobility or intrinsic sphincter deficiency (ISD). Incontinence associated with urethral hypermobility has been called anatomic incontinence, since the incontinence is due to malposition of the sphincter unit. Displacement of the proximal urethra below the level of the pelvic floor does not allow for the transmission of abdominal pressure that normally aids in closing the urethra. There are women with mobility of the bladder neck or urethra who do not experience incontinence. ISD was initially felt to occur after failure of one or more operations for stress incontinence. Other causes of ISD include myelodysplasia, trauma, and radiation. Some authors have theorized that all incontinent patients must have an element of ISD in order to actually leak. The patient with stress incontinence will leak urine with any sudden increase in abdominal pressure. In patients with severe ISD the increase in abdominal pressure required to cause leakage is small, and therefore patients may leak urine with minimal activity.
Evaluation of the Incontinent Patient
The evaluation of the incontinent patient includes a history and a physical, laboratory tests and possibly urodynamic testing. The onset, frequency, severity and pattern of incontinence should be sought, as well as any associated symptoms such as frequency, dysuria, urgency or nocturia. Incontinence may be quantified by asking the patient if he or she wears a pad and how often the pad is changed. Obstructive symptoms, such as a feeling of incomplete emptying, hesitancy, straining or weak stream, may coexist with incontinence, particularly in males and in female patients with previous incontinence procedure, cystoceles or poor detrusor contractility. Female patients should be asked about symptoms of pelvic prolapse, such as recurrent urinary tract infection, a sensation of vaginal fullness or pressure, or the observation of a bulge in the vagina. All incontinent patients should be asked about bowel function and neurologic symptoms. Response to previous treatments, including drugs, should be noted. Important features of the history include previous gynecologic or urologic procedures, neurologic problems and past medical problems. A list of the patient's current medications, including use of over-the-counter medications, should be obtained.
Although the history may define the patient's problem, it may be misleading. Urge incontinence may be triggered by activities such as coughing, so that according to the patient's history, he or she would seem to have stress incontinence. A patient who complains only of urge incontinence may also have stress incontinence. Mixed incontinence is very common, with at least 65% of patients with stress incontinence having associated urgency or urge incontinence.
A complete physical examination is performed with emphasis on a neurologic assessment and the abdominal, pelvic and rectal examination. In females, the condition of the vaginal mucosa and the degree of urethral mobility is determined. Simple pelvic examination with the patient supine is sufficient to determine if the urethra moves with straining or coughing. The degree of movement is not as important as the determination of whether movement occurs. In the patient with suspected stress incontinence urethral leakage with a cough or a stress maneuver must be demonstrated prior to invasive treatment. The presence of associated pelvic organ prolapse should be noted as it can contribute to the patient's voiding problems and may have an impact on diagnosis and treatment. A rectal exam in both males and females includes the evaluation of sphincter tone and perineal sensation.
A urinalysis is performed to determine if there is any evidence of hematuria, pyuria, glucosuria, or proteinuria. A urine specimen is sent for cytology if there is hematuria and/or irritative voiding symptoms. The urine is cultured if there is pyuria or bacteriuria. Infection should be treated prior to further investigations or interventions. Hematuria, greater than 3 red cells per high powered field, warrants further investigation.
A post void residual (PVR) should be measured either with pelvic ultrasound or directly with a catheter. A normal PVR is less than 50 mL and a PVR in excess of 200 mL is abnormal. A significant PVR urine may reflect either bladder outlet obstruction or poor bladder contractility. The only way to distinguish outlet obstruction from poor contractility is with urodynamic testing.
A voiding diary may be used to quantitiate the amount of fluid taken in, the amount of urine per void, the number of voids and the number of incontinent episodes.
A pad weight test is done to quantitate the amount of incontinence which is important in counseling male patients about their treatment options.
Urodynamic testing is used to accurately diagnose the etiology of patient's incontinence however many patients can be successfully treated without urodynamic testing. The purpose of urodynamics is to examine bladder compliance, to diagnose stress incontinence and to rule out obstruction as a cause of either overflow or urge incontinence. Urodynamics are often done prior to invasive therapies and should always be done in patients undergoing repeat procedures following failed procedures.
Treatment of Urinary Incontinence
The patient with urge incontinence needs to understand that they leak urine because their bladder contracts with little or no warning. The first line of treatment is timed voiding. Often, reminding patients to void every one to two hours during the day, before they get an urge to void, will result in them staying dry. Other behavioral interventions such as modification of fluid intake, avoidance of bladder irritants, or bladder retraining, where the patient attempts to consciously delay voiding and to increase the interval between voids, may also have a role in the treatment of urge incontinence. Pelvic muscle exercises can be used to abort a detrusor contraction provided that the patient gets a warning of needing to void prior to the detrusor contraction starting.
Anticholinergic-antimuscarinics are the mainstay of medical therapy in achieving continence. The side effects of anticholinergics include urinary retention, dry mouth, constipation, nausea, blurred vision, tachycardia, drowsiness and confusion. They are contraindicated in patients with narrow-angle glaucoma. Anticholinergic-antimuscarinics are also used to decrease bladder pressure in patients with poor compliance. Anticholinergic-antimuscarinics are combined with clean intermittent catheterization in patients who have a significant PVR prior to treatment, or in patients who develop retention while on anticholinergics.
Patients with intractable detrusor over activity may require surgical intervention, consisting of neuromodulation with a sacral nerve stimulator or various forms of bladder augmentation. Injection of the detrusor muscle with botulinum toxin (Botox ) has also been successfully used although this a non-approved use.
The primary goal in treating the patient with poor bladder compliance is to treat the high bladder pressure. Complete bladder emptying with clean intermittent catheterization combined with anticholinergics will often lower bladder pressure to a safe range. A combination of anticholinergic-antimuscarinics and alpha-agonists may be required in some patients. Bladder augmentation is required when medical management fails.
Overflow incontinence is treated by emptying the bladder. If the cause of overflow is obstruction, then relieving the obstruction should lead to improved emptying. Anatomic obstruction in males is from either urethral stricture disease or prostatic obstruction. Depending on the severity of urethral stricture disease the patient may require a urethral dilation, internal urethrotomy or a urethroplasty. Prostatic obstruction may be treated in a variety of ways but transurethral resection remains the "gold standard." If a woman is obstructed from previous surgery or from pelvic prolapse, she may benefit from a urethrolysis or surgical correction of the prolapse. Clean intermittent catheterization is an option in the obstructed patient who does not want or could not tolerate further surgery.
The patient with overflow incontinence secondary to poor detrusor contractility is best treated with clean intermittent catheterization.
Indwelling catheters are not an optimum long term treatment modality in the treatment of incontinence. All patients with indwelling catheters will have infected urine which predisposes them to bladder calculi and ultimately to squamous cell carcinoma of the bladder. Any foreign object in the bladder can cause or exacerbate elevated bladder pressure which then causes hydronephrosis, ureteral obstruction, renal stones and eventually renal failure.
The amount of incontinence and how it affects the patient will often determine the aggressiveness of treatment. The patient who is severely restricted because of severe leakage with minimal movement may not want to try medical therapy but may opt for surgical treatment, whereas the patient who leaks small amounts infrequently may choose conservative treatment. Pelvic floor exercises can improve anatomic stress urinary incontinence by augmenting closure of the external urethral sphincter and by preventing descent and rotation of the bladder neck and urethra. To benefit from the exercises, women must be taught to do them properly and they must do them. Adjuncts to learning pelvic floor exercises include weighted vaginal cones, a perineometer or electrical stimulation.
Alpha-agonists such as pseudoephedrine (Sudafed) may be used for the treatment of stress incontinence. The bladder neck and proximal urethra have abundant alpha receptors. Activation of these receptors by alpha-agonists leads to an increase in smooth muscle tone. The usual dose is twice daily, but some women who are incontinent with exercise may benefit from taking an alpha-agonist one hour before exercise. Tricyclic antidepressants, such as imipramine (Tofranil), although not approved for incontinence, have both alpha-agonist and anticholinergic properties.
Pessaries that support the bladder neck can also provide relief to the patient with stress incontinence.
Surgical therapy for stress incontinence is indicated when a patient doesn't wish to pursue non surgical therapy or if medical treatment has failed. The type of surgical therapy depends on the diagnosis. Patients who have anatomic stress incontinence can benefit from a variety of surgical repairs that restore the bladder neck to its normal retropubic position, retropubic bladder neck suspensions, or improves urethral support, sling procedures. Patients with intrinsic sphincter deficiency usually have a well-supported bladder neck. These patients require a procedure that will close or coapt the proximal urethra. Coaptation may be achieved with a variety of bulking agents that are injected into the bladder neck or proximal urethra.
A pubovaginal sling which is placed at the bladder neck is the ideal procedure for the patient with both intrinsic sphincter deficiency and anatomic stress incontinence, as a sling will coapt the proximal urethra and restore the bladder neck to its normal location.
Synthetic mid urethral slings are ideal for the patient with anatomic stress incontinence who is looking for a surgery with minimal recovery time. In a randomized surgical trials for stress incontinence the TVT mid urethral sling has been shown to be comparable to a Burch colposuspenion which is a retropubic suspension at 6, 12 and 24 months. Due to concerns of bladder, bowel or major vessel injury slings have been developed that are placed transversely underneath the mid urethra from one obturator foramina to the other. The advantage of this sling is that the retropubic space is avoided. These slings do have more groin issues with pain and or numbness at the site of the sling at the top of the leg. Infection, although exceedingly rare, may result in necrotizing fasciitis. A randomized surgical trial by the NIH comparing a TVT mid urethral sling to two different obturator slings, Monarc and TOT, showed that no procedure is superior to the other.
The newest synthetic slings are very small, approx 4-6 cm, and therefore have none or less retropubic or obturator issues such as vessel injury or exit site pain. One year outcome data is promising but more work needs to be done to sort out which patients are best treated with these procedures.
Male patients with stress incontinence can be treated with an artificial urinary sphincter or a variety of sling procedures. An artificial urinary sphincter provides continence because a cuff compresses the bulbar urethra. It is considered the gold standard treatment. Male slings provide compression under the urethra and elevate the urethra to a more retropubic position. Slings are best suited for men with lesser degrees of incontinence as determined by a pad weight test.
Stress and urge incontinence often coexist. Burgio et. al. have advocated pelvic muscle exercises with biofeedback for the treatment of stress and urge incontinence. Behavioral therapy can result in a reduction in incontinence episodes and a patient perceived improvement.
Imipramine is beneficial in patients with mixed (stress and urge) incontinence. The recommended dose is 10 to 25 mg, three times daily.
Seventy percent of patients with combined incontinence (stress and urge) will be relieved of urge incontinence following a procedure for stress incontinence. Patients whose urge incontinence does not respond to anticholinergics preoperatively may have a good response to anticholinergics once their stress incontinence is treated.
Indications to Refer to Urology
The main indication to refer the patient with incontinence to urology is failure to respond to medical therapy. There is no reason that an internist or family doctor can't do a basic work-up (history, physical, urinalysis, +/- PVR) and consider medical therapy. If the patient fails to respond adequately to medical therapy then referral is warranted. The presence of hematuria, recurrent infections or complicated incontinence, such as following radical prostatectomy in a male, or that thought to be neurogenic, should always prompt a referral.
Key Diagnostic Points
Overview of Treatments
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