WHAT IS URINARY INCONTINENCE?
- 1WHAT IS THE MEANING OF URINARY INCONTINENCE?
- Urinary incontinence (UI) is the complaint of involuntary leakage of urine.
- 2WHAT ARE THE CAUSES OF URINARY INCONTINENCE?
- The urethral sphincter, a combination of smooth and striated muscles within and external to the urethra, maintains adequate resistance to the flow of urine from the bladder until voluntary voiding is initiated.
- Volitional and involuntary bladder contractions are mediated by activation of postsynaptic muscarinic receptors by acetylcholine. Bladder smooth muscle cholinergic receptors are mainly of the M2 variety; however, M3 receptors are responsible for both emptying contraction of normal micturition and involuntary bladder contractions, which can result in UI. Therefore, most pharmacologic antimuscarinic therapy is anti-M3 based.
- UI occurs as a result of overactivity or underactivity of the urethra, bladder, or both.
- Urethral underactivity is known as stress UI (SUI) and occurs during activities such as exercise, running, lifting, coughing, and sneezing. The urethral sphincter no longer resists the flow of urine from the bladder during periods of physical activity.
- Bladder overactivity is known as urge UI (UUI) and is associated with increased urinary frequency and urgency, with or without urge incontinence. The detrusor muscle is overactive and contracts inappropriately during the filling phase.
- Urethral overactivity and/or bladder underactivity is known as overflow incontinence. The bladder is filled to capacity but is unable to empty, causing urine to leak from a distended bladder past a normal outlet and sphincter. Common causes of urethral overactivity include benign prostatic hyperplasia; prostate cancer; and, in women, cystocele formation or surgical overcorrection after SUI surgery.
- Mixed incontinence includes the combination of bladder overactivity and urethral underactivity.
- Functional incontinence is not caused by bladder- or urethra-specific factors but rather occurs in patients with conditions such as cognitive or mobility deficits.
- Many medications may precipitate or aggravate voiding dysfunction and UI (Table 1–1).
(ACEIs, angiotensin-converting enzyme inhibitors.)
- 3WHAT ARE THE SIGNS AND SYMPTOMS OF URINARY INCONTINENCE?
- Signs and symptoms of UI depend on the underlying pathophysiology (Table 1–2). Patients with SUI generally complain of urine leakage with physical activity, whereas those with UUI complain of frequency, urgency, high-volume incontinence, and nocturia and nocturnal incontinence.
- Urethral overactivity and/or bladder underactivity is a rare but important cause of UI. Patients complain of lower abdominal fullness, hesitancy, straining to void, decreased force of stream, interrupted stream, and sense of incomplete bladder emptying. Patients can also have urinary frequency, urgency, and abdominal pain.