Urinary incontinence is defined as involuntary leakage of urine. This contrasts with urine that leaks from extraurethral sources, such as fistulas or lower urinary tract congenital malformations. Although incontinence is categorized into several forms, this chapter focuses on the evaluation and management of stress and urgency urinary incontinence. Stress urinary incontinence (SUI) is the involuntary leakage of urine with increases in intraabdominal pressure. Urgency urinary incontinence is the involuntary leakage accompanied or immediately preceded by a perceived strong imminent need to void. A related condition, overactive bladder, describes urinary urgency with or without incontinence and usually with greater daytime urinary frequency and nocturia (Abrams, 2009).
According to International Continence Society guidelines, urinary incontinence is a symptom, a sign, and a condition (Abrams, 2002). For example, with SUI, a patient may complain of involuntary urine leakage with exercise or laughing. Concurrent with these symptoms, involuntary leakage from the urethra synchronous with cough or Valsalva may be observed during examination by a provider. And as a condition, SUI is objectively demonstrated during urodynamic testing if involuntary leakage of urine accompanies increased abdominal pressure and absence of detrusor muscle contraction. Under these circumstances, when the symptom or sign of SUI is confirmed with objective testing, the term urodynamic stress incontinence is preferred.
With urgency urinary incontinence, women have difficulty postponing urination urges and generally must promptly empty their bladder on cue and without delay. Common triggers are hand washing, running water, or exposure to cold. Urgency urinary incontinence is sometimes objectively demonstrated during urodynamic testing to correspond temporally with spontaneous detrusor muscle contractions—a condition termed detrusor overactivity. When both stress and urgency symptoms are present, it is called mixed urinary incontinence.
In Western societies, epidemiologic studies indicate a prevalence of urinary incontinence of 25 to 51 percent and even higher among nursing home patients (Buckley, 2010; Markland, 2011). This wide range is attributed to variations in research methodologies, population characteristics, and definitions of incontinence. As part of the 2005 to 2006 National Health and Nutrition Examination Survey (NHANES), urinary incontinence characterized by participants as moderate to severe leakage was identified in 16 percent (Nygaard, 2008). A subsequent review of NHANES confirmed a similar rate of 17 percent (Wu, 2014). Among ambulatory women with urinary incontinence, SUI represents 29 to 75 percent of cases. Urgency urinary incontinence accounts for up to 33 percent, whereas the remainder is attributable to mixed forms (Hunskaar, 2000). However, current available data are limited by the fact that most women do not seek medical attention for this condition (Hunskaar, 2000). It is estimated that only one in four women will seek medical advice for incontinence, due to embarrassment, limited health-care access, or poor screening by health-care providers (Hannestad 2002; Minassian, 2012).