Urge incontinence and overactive bladder

Definition

• A sudden, compelling urge to void that is difficult to hold and often results in involuntary leakage of urine.
• Leakage is usually of moderate to large volume and occurs immediately after the urgent, irrepressible need to void.
• Overactive bladder is defined as urgency, usually with frequency and nocturia, with or without urge incontinence and in the absence of urinary tract infection or other obvious pathology.

Occurrence & epidemiology

Epidemiology

• Urge incontinence is the most common type of incontinence in older adults but also occurs in younger people.
• Urinary incontinence overall affects approximately 37% of older women worldwide.

Aetiopathogenesis

Why urge incontinence develops

• Basic mechanism: involuntary detrusor contractions during the filling phase.
• The umbrella term: overactive bladder, divided into OAB dry without and OAB wet with urine loss.

Aetiology and pathogenesis

• The most common cause is detrusor overactivity with involuntary contractions during filling, usually when the bladder is partially or nearly full.
• Detrusor overactivity may be idiopathic or result from dysfunction of frontal brain areas that suppress micturition, for example due to ageing, dementia or stroke, or from outlet obstruction.
• Neurological causes of overactive bladder include multiple sclerosis, spinal cord injury, Parkinson disease, stroke and dementia.
• It is often precipitated by diuretics; in women, atrophic vaginitis, common with ageing, contributes to urethral irritation and urgency.

Clinical features

• Typical features are urgency, frequent voiding, nocturia and nocturnal incontinence.
• Urgency or an abrupt gush of urine without warning or preceding rise in intra-abdominal pressure typically indicates detrusor overactivity.
• Older adults with urgency are at increased risk of falls and fractures.

Diagnosis

• In the cough stress test, delayed or persistent leakage suggests cough-triggered detrusor overactivity, whereas immediate leakage that starts and stops with the cough indicates stress incontinence.
• Urinalysis, urine culture and kidney function tests are part of the basic work-up; a post-void residual below 50 mL is normal.
• A voiding diary kept over 48 to 72 hours records the time and volume of each void and each incontinent episode.
• If filling of less than 300 mL triggers urgency or contractions on cystometry, detrusor overactivity and urge incontinence are likely.

Keep learning in the app

Further reading (selection)

1. StatPearls: Urge Incontinence (NCBI Bookshelf)
2. MSD Manual Professional: Urinary Incontinence in Adults
3. Overactive Bladder Symptoms Within Nervous System: A Focus on Etiology (Front Physiol 2021, PubMed Central)
4. DocCheck Flexikon, Harninkontinenz

Cross-references