genitourinary disorders
Urinary Incontinence in Adults
Etiology of Urinary Incontinence in Adults
The disorder tends to differ among age groups. With aging, bladder capacity decreases, ability to inhibit urination declines, involuntary bladder contractions (detrusor overactivity) occur more often, and bladder contractility is impaired. Thus, voiding becomes more difficult to postpone and tends to be incomplete. Postvoid residual volume increases, probably to≤100 mL (normal<50 mL). Endopelvic fascia weakens. In postmenopausal women,decreasedestrogenlevels lead to atrophic urethritis and atrophic vaginitis and to decreasing urethral resistance, length, and maximum closure pressure. In men,prostate size increases, partially obstructing the urethra and leading to incomplete bladder emptying and strain on the detrusor muscle. These changes occur in many normal, continent older adults and may facilitate incontinence due to another cause, but increased prostate size alone does not cause incontinence. In younger patients,self-limited conditions such as urinary tract infection or vaginitis may cause transient incontinence. In such cases, it often begins suddenly, may cause little leakage, and usually resolves quickly with little or no treatment. Often, incontinence has a single cause in younger patients but may have several causes in older adults. Conceptually, categorization into reversible (transient) or established causes may be useful. However, causes and mechanisms often overlap and occur in combination. nfection (commonly, symptomatic Introduction to Urinary Tract Infections (UTIs) ), Established incontinence is caused by a persistent problem affecting nerves or muscles. Mechanisms usually used to describe these problems are bladder outlet incompetence or obstruction, detrusor overactivity or underactivity, detrusor-sphincter dyssynergia, or a combination (see table). However, these mechanisms are also involved in some transient causes. Outlet incompetenceis a common cause of stress incontinence. In women, it is usually due to weakness of the pelvic floor or of the endopelvic fascia. Such weakness commonly results from multiple vaginal deliveries, pelvic surgery (including hysterectomy), age-related changes (including atrophic urethritis), or a combination. As a result, the vesicourethral junction descends, the bladder neck and urethra become hypermobile, and pressure in the urethra falls below that of the bladder. In men, a common cause is damage to the sphincter or to the bladder neck and posterior urethra after radical prostatectomy. is a common cause of incontinence in men, although most men with obstruction are not incontinent. Obstruction in men commonly results from Benign Prostatic Hyperplasia (BPH) , Obstruction leads to a chronically overdistended bladder, which loses its ability to contract; then the bladder does not empty completely, resulting in overflow. Obstruction also may lead to detrusor overactivity and urge incontinence. If the detrusor muscle loses its ability to contract, overflow incontinence may follow. Some causes of outlet obstruction (eg, large bladder diverticula, cystoceles, bladder infections, calculi, and tumors) are reversible. is a common cause of urge incontinence in older and younger patients. The detrusor muscle contracts intermittently for no apparent reason, usually when the bladder is partially or nearly full. Detrusor overactivity may be idiopathic or may result from dysfunction of the frontal micturition inhibitory center (commonly due to age-related changes, dementia, or stroke) or outlet obstruction. Detrusor overactivity (hyperactivity) with impaired contractility is a variant of urge incontinence characterized by urgency, Urinary Frequency , a weak flow rate, is a term sometimes used to describe urinary urgency (with or without incontinence) that is often accompanied by Urinary Frequency and nocturia. causes urinary retention and overflow incontinence in about 5% of patients with incontinence. It may be caused by Spinal Trauma or to nerve roots supplying the bladder (eg, by disk compression, tumor, or surgery), by peripheral or autonomic neuropathies, or by other neurologic disorders (see table Detrusor-sphincter dyssynergia(loss of coordination between bladder contraction and external urinary sphincter relaxation) may cause outlet obstruction, with resultant overflow incontinence. Dyssynergia is often due to a spinal cord lesion that interrupts pathways to the pontine micturition center, which coordinates sphincter relaxation and bladder contraction. Rather than relaxing when the bladder contracts, the sphincter contracts, obstructing the bladder outlet. Dyssynergia causes severe trabeculation, diverticula, a “Christmas tree” deformation of the bladder seen on cystogram, hydronephrosis, and renal failure. Functional impairment(eg, cognitive impairment, reduced mobility, reduced manual dexterity, coexisting disorders, lack of motivation), particularly in older patients, may contribute to established incontinence but rarely causes it. 