Urinary Incontinence

– Involuntary leakage of urine classified as instability incontinence (sudden urgent desire or detrusor contraction with immediate loss of control), stress incontinence (loss of control on sneezing, coughing, laughing, or straining), overflow incontinence (chronic overdistention of the bladder that results in dribbling), and constant incontinence (continual dribbling).

Causes and Incidence

Causes vary by classification. Instability incontinence is often associated with disease or trauma of the central nervous system (e.g., cerebrovascular accident, parkinsonism, brain tumors, spinal cord injury); bladder outlet obstructions (e.g., benign prostatic hypertrophy); bladder infection; and bladder irritation (e.g., calculi). Other causes of instability incontinence remain unclear and are labeled idiopathic.

Stress incontinence is caused by pelvic relaxation or sphincter incompetence. Pelvic relaxation leads to cystocele, rectocele, or uterine prolapse. Factors associated with relaxation include multiparity, aging, peripheral neuropathy and diabetes, and extensive pelvic surgery. Sphincter incompetence is associated with any factor that loosens the sphincter, such as prostate or urinary surgery or repeat urinary procedures, infection, or a reduction in mucus production.

The two causes of overflow incontinence are deficient detrusor function and bladder outlet obstruction. Detrusor function deficiency is associated with cauda equina syndrome, multiple sclerosis, tabes dorsalis, polio, herpes zoster, pelvic trauma, diabetes, and chronic overdistention. Obstruction is associated with inflammation, benign prostatic hypertrophy, adenocarcinoma of the bladder, urethral stricture in men, and urethral distortion in women.

Constant incontinence results from bypassing of normal sphincter function and failure of the bladder to store urine. Associated factors include urinary fistula, epispadias, urethral etopia, and surgical conduit.

It is estimated that at least 10 million individuals suffer from incontinence in the United States. It occurs in both men and women and increases with age. As many as 50% of institutionalized elderly individuals experience chronic incontinence, and 20% more experience intermittent incontinence.

Disease Process

Stress incontinence occurs when the bladder pressure exceeds the urethral closure pressure. This happens when the urethra is no longer maintained in a normal anatomic position, resulting in inefficient transmission of abdominal pressures along the length of the urethra. Thus sudden increases in abdominal pressure from coughing, sneezing, or straining are not transmitted to the sphincter, and it does not tighten.

Instability incontinence is a result of inappropriate contraction of the detrusor muscle, with loss of coordination between bladder contraction and sphincter release. Overflow incontinence results when the detrusor muscle fails to contract, allowing the bladder to overfill, or when the bladder outlet is blocked and urine backs up and overfills the bladder. Constant incontinence occurs when the sphincter is bypassed and the urine has a new channel or outlet, such as a fistula between the bladder or urethra and the vagina or rectum.

Symptoms

Involuntary loss of urine is the chief manifestation, and the pattern varies by classification of the incontinence. Abdominal distention and associated urinary tract infection (UTI) are also seen in overflow incontinence.

Potential Complications

Complications include UTI, kidney infection, and skin breakdown.

Diagnostic Tests

Voiding cystourethrography
Stress incontinence: pelvic descent below the pubis, urethral excursion, and leakage of contrast material with straining Instability: detrusorsphincter dyssynergia Overflow: large bladder capacity, possible blockage Constant: leakage of contrast material through fistula or ectopic structure.

Urodynamic testing
Stress: normal capacity, sensations, and compliance; stable detrusor; normal electromyographic (EMG) explosive flow with low-pressure detrusor contraction Instability: decreased functional capacity, early sensation, normal compliance, unstable detrusor, normal EMG findings Overflow with detrusor dysfunction: enlarged capacity, delayed sensations, abnormal compliance, poor stream, residuals Overflow with obstruction: normal or enlarged capacity, normal or delayed sensation, normal or impaired compliance, high detrusor contraction with poor flow Constant: impaired urine storage with fistulous tract.

Treatments

Surgery
Stress: vesicourethral suspension to elevate anatomic structures; artificial urinary sphincter, pubovaginal sling to replace or reinforce damaged sphincter Instability: urinary diversions (e.g., suprapubic catheter or ileoconduit) Overflow: transurethral resection of enlarged prostate; urethrotomy to correct urethral stricture; reconstruction of bladder or urethra Constant: repair or removal of ectopic structures or fistulas.

Drugs
Autonomic drugs, spasmolytics to increase detrusor contractility and tone; autonomic drugs to increase or decrease bladder neck tone; muscle relaxants to diminish external muscle tone; antispasmodics to decrease detrusor spasms.

General
Stress: Kegel exercises to strengthen periurethral muscles; electrostimulation therapy to strengthen pelvic muscles; use of pessary to alter anatomic structure Instability: use of a timed voiding schedule; manipulation of fluid intake, avoiding largevolume intake periods; intermittent catheterization Overflow: double voiding techniques; intermittent catheterization; voiding schedules with manual Crede’s maneuvers Other: good skin care with use of barrier cream to protect irritated skin from moisture and urine; use of incontinence aids (e.g., pads, adult diapers, odor elimination substances, external catheters); referral to continence support group; instruction in intermittent catheterization techniques if needed.