CHAPTER 31 Urinary incontinence
Urinary incontinence is a common problem, particularly in older adults. It is so common in older women that some think of it as “normal.” The prevalence in U.S. women is 26% during reproductive years and 30% to 40% in postmenopausal years. In noninstitutionalized elderly women, the prevalence is 15% to 30%, and in men it is 8% to 22%. In elderly persons in nursing homes, the rate rises to almost 50%.
Urinary incontinence in adults is categorized according to the underlying anatomical or physiological impairment—specifically, stress incontinence, urge incontinence (overactive bladder), overflow incontinence, and incontinence from reversible causes.
Stress incontinence is leakage of urine during activities that increase abdominal pressure, such as coughing, sneezing, laughing, or other physical activities. It occurs most often in females and is caused by hypermotility at the base of the bladder and urethra associated with pelvic floor relaxation or intrinsic urethral weakness.
Urge incontinence is an abrupt and strong desire to void with the inability to delay urination and is caused by bladder hyperactivity or hypersensitive bladder. Detrusor muscle overactivity occurs when pathological brain disorders interfere with central inhibitory centers and fail to prevent detrusor muscle contractions.
Overflow incontinence occurs with overdistention of the bladder caused by an underactive or acontractile detrusor muscle; by sphincter-detrusor dyssynergia, which is loss of the synergistic urinary sphincter relaxation that normally occurs with bladder detrusor muscle contraction; or from bladder outlet or urethral obstruction. Sphincter weakness can occur from damage to the urethra or its innervation or from pelvic floor muscle relaxation.
Incontinence from reversible factors originates outside of the lower urinary tract and is caused by mental status impairment, immobility, or medication. Some sources term this functional or transient incontinence.
A final category of incontinence is called mixed incontinence. This occurs when the incontinence is produced as the result of several anatomical, physiological, or functional factors. Involuntary discharge of urine in children is abnormal beyond the age of 4 years for daytime wetting and beyond the age of 6 for nighttime wetting. Daytime wetting constitutes diurnal enuresis; nighttime wetting is known as nocturnal or sleep enuresis. In children, enuresis may be organic or nonorganic; nonorganic enuresis can be primary or secondary. Primary nonorganic enuresis occurs in 75% to 90% of children. This enuresis is defined as wetting that has continued since infancy without an established pattern of dryness. Secondary nonorganic enuresis occurs in 10% to 25% of children and is defined as recurrence of wetting after continence has been established for at least 6 months. The possibility of abnormal urinary anatomy is high in young children who present with urinary tract symptoms.
Diagnostic reasoning: focused history
Adults
Could this be the result of reversible factors (see box 31-1)?
Key questions
What medications are you taking?
Do you have any of the following urinary symptoms: urgency, frequency, burning, pain, blood in the urine, flank pain?
Do you have vaginal dryness or itching?
Do you have pain/discomfort with sexual activity?
Have you had changes in bowel function?
When was your last bowel movement?
Are you feeling depressed or “blue”?
Are you aware of incontinence?
Are you able to get to the toilet easily?
Box 31-1 Reversible Factors that Can Cause Urinary Incontinence in Adults
| D | Delirium, dementia, depression |
| I | Infection |
| A | Atrophic vaginitis/urethritis |
| P | Pharmaceuticals |
| E | Endocrine/excess urine production |
| R | Restricted mobility, retention |
| S | Stool impaction |
Modified from Resnick NM: Initial evaluation of the incontinent patient, J Am Geriatr Soc 38:311, 1990.
Medications
Hypnotic-sedatives, diuretics, anticholinergic agents, adrenergic agents, and calcium channel blockers can cause incontinence. α-Adrenergic agonists and β-adrenergic agonists increase sphincter tone and may cause retention. Anticholinergics, prostaglandin inhibitors, calcium channel blockers, and narcotic analgesics decrease detrusor tone. Diuretics can cause incontinence because of increased production of urine. Central nervous system (CNS) depressants, such as hypnotic-sedatives, can interfere with functional ability.
Table 31-1 lists categories of medications and their mechanism of action in urinary incontinence.
Table 31-1 Medications that Can Cause or Contribute to Urinary Incontinence
| MEDICATION CATEGORY | TYPE OF INCONTINENCE | MECHANISM OF ACTION |
|---|---|---|
| Anticholinergics | Overflow | Decreased bladder contractions with retention |
| Antidepressants | Overflow | Decreased bladder contractions with retention |
| Antipsychotics | Overflow | Decreased bladder contractions with retention |
| Sedative-hypnotics | Overflow | Decreased bladder contractions with retention |
| Antihistamines | Overflow | Decreased bladder contractions with retention |
| Narcotics | Overflow | Decreased bladder contractions with retention |
| Alcohol | Overflow | Decreased bladder contractions with retention |
| Calcium channel blockers | Overflow | Decreased bladder contractions with retention |
| β-Adrenergic agonists | Overflow | Decreased bladder contractions with retention |
| α-Adrenergic agonists | Overflow | Sphincter contraction with outflow obstruction |
| α-Adrenergic antagonists | Stress | Sphincter relaxation with urinary leakage |
| Diuretics | Urge | Contractions stimulated by high urine flow |
| Caffeine | Urge | Diuretic effect |
| Sedative-hypnotics | Urge | Depressed CNS inhibition of micturition |
| Alcohol | Urge | Diuretic effect and depressed CNS inhibition |
Adapted from Weiss BD: Diagnostic evaluation of urinary incontinence in geriatric patients, Am Fam Physician 57:2675, 2688, 1998.
Urinary tract infection, vaginal dryness, and dyspareunia
Urinary tract infection (UTI) and atrophic vaginitis can cause incontinence through local irritation and loss of muscle tone.
Bowel function
Fecal impaction can cause incontinence through mechanical obstruction of the urethra.
Mental status, mobility, and chronic health problems
Excessive urine production may be a problem if mobility is restricted, health is poor, or orientation is variable. Chronic health problems, psychological factors, and restricted mobility can result in incontinence because of loss of functional ability and/or mentation.
What do the presenting symptoms tell me?
Key questions
What is the primary symptom (e.g., urgency; dribbling; lack of sensation; nocturia; abdominal discomfort; leakage with laughing, coughing, or sneezing)?
How frequently do you urinate?
How much urine is voided each time?
Do you have difficulty starting to urinate?
Does your urine stream start and stop while you are urinating?
Primary symptom
Urgency is the primary symptom of detrusor instability. Dribbling indicates overflow incontinence, and sphincter weakness usually increases with postural changes. Men often report nocturia and dribbling with overflow incontinence. Abdominal discomfort often occurs with overflow incontinence because of bladder distention. Incontinence with an increase in intraabdominal pressure is usually stress incontinence but can also be the result of detrusor overactivity and bladder irritability.
Frequency of voiding
Increase in frequency of voiding occurs with detrusor instability or hyperactivity and may occur with some transient causes such as use of diuretics or large-volume fluid intake. Decreased frequency is common in overflow incontinence.
Amount of urine lost with each episode
Involuntary loss of small amounts of urine occurs with stress incontinence and overflow incontinence.
Character of stream
Voiding a small-caliber or intermittent stream or difficulty in starting the stream indicates obstructive uropathy. In males, this may be secondary to an enlarged prostate.
Fluid intake
A significant increase in the amount of fluid intake or an unusually large volume may indicate diabetes mellitus (DM). Caffeine and alcohol can act as diuretics and may be a cause of reversible incontinence. Caffeine can also be a bladder irritant and either produce or exacerbate urge incontinence. A large volume of fluid intake may produce enuresis secondary to a large urine volume, particularly if fluids are consumed in the evening before bedtime.
Children
Is this primary or secondary enuresis?
Key question
Primary enuresis occurs when a child has never achieved consistent dryness. Secondary enuresis is involuntary voiding of urine in a child who has had a period of dryness of more than 6 months. Secondary enuresis is often indicative of some other form of voiding dysfunction or significant underlying pathology. In children, daytime urinary incontinence beyond the age of 4 years may indicate congenital abnormalities in the urinary tract or nervous system.
Is this organic enuresis?
Key questions
Does the child have pain on urination?
Does the child have intermittent daytime wetness?
Does the child seem thirsty and urinate a lot?
Has the child had nervous system trauma?
Does the child have constipation or encopresis?
Does the child have constant wetness or dribbling throughout the day?
Does the child have an abnormal stream, such as dribbling or hesitancy?
Has the child had a change in gait?
Has the child had a recent lumbar puncture?
Does the child snore or have apnea at night?
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