Overview
Urge Urinary Incontinence (OAB)
1. Clinical Overview
Summary
Urge urinary incontinence (UUI) is the involuntary leakage of urine accompanied by or immediately preceded by urgency. It is a component of overactive bladder (OAB) syndrome, which also includes urgency, frequency, and nocturia. UUI is caused by detrusor overactivity.
Key Facts
| Aspect | Detail |
|---|---|
| Definition | Involuntary leakage with urgency |
| Mechanism | Detrusor overactivity |
| Key Symptom | "Can't make it to the toilet in time" |
| Classic Scenario | "Latchkey incontinence" (leaking when putting key in door) |
| First-Line | Bladder training + anticholinergics/beta-3 agonist |
Clinical Pearls
- OAB vs UUI: OAB syndrome may be "wet" (with UUI) or "dry" (urgency/frequency without leakage)
- Neurological cause: Always ask about back pain, leg weakness, numbness (cauda equina)
- Anticholinergic burden: Watch cognitive impairment in elderly
- Mirabegron: Alternative without anticholinergic side effects
2. Epidemiology
Prevalence
| Population | Prevalence |
|---|---|
| Adults | 10-15% |
| Women >65 | Up to 30% |
| Increases with age | Both sexes |
Risk Factors
| Risk Factor | Association |
|---|---|
| Age | Increases prevalence |
| Neurological disease | MS, stroke, Parkinson's |
| Obesity | Increased bladder pressure |
| UTI | Can precipitate/worsen |
| Caffeine/alcohol | Bladder irritants |
| Previous pelvic surgery |
3. Pathophysiology
Mechanism
Normal Bladder Filling
↓
Detrusor Relaxation (sympathetic)
↓
Gradual Stretch → First Sensation → Urge
↓
Voluntary Voiding (parasympathetic)
IN OAB:
Abnormal Detrusor Contractions During Filling
↓
Involuntary Urgency
↓
URGE INCONTINENCE (if can't suppress)
Causes
| Category | Examples |
|---|---|
| Idiopathic | Most common |
| Neurogenic | MS, stroke, Parkinson's, spinal cord injury |
| Bladder pathology | Infection, stones, tumour |
| Outlet obstruction | BPH (secondary detrusor overactivity) |
4. Clinical Presentation
Core Symptoms (OAB)
| Symptom | Definition |
|---|---|
| Urgency | Sudden compelling desire to void, difficult to defer |
| Frequency | Voiding >8 times/day |
| Nocturia | Waking ≥1 time at night to void |
| Urge incontinence | Leakage with urgency |
Distinguishing Stress vs Urge Incontinence
| Feature | Stress Incontinence | Urge Incontinence |
|---|---|---|
| Trigger | Cough, sneeze, exercise | Urgency, key in door |
| Leak volume | Small spurts | Larger volumes |
| Precipitants | Physical exertion | Sound of water, cold |
| Warning | None | Strong urge |
| Mechanism | Sphincter weakness | Detrusor overactivity |
Mixed Incontinence
Combination of stress and urge - treat predominant component first
Common presentation.
5. Clinical Examination
Examination Components
| Component | Purpose |
|---|---|
| Abdominal | Palpable bladder (retention) |
| Vaginal/pelvic | Prolapse, urethral mobility |
| Neurological | Lower limb sensation, reflexes, perineal sensation |
| Cough stress test | Provoke SUI |
Red Flags (Urgent Referral)
| Finding | Concern |
|---|---|
| Haematuria | Malignancy |
| Recurrent UTI | Underlying pathology |
| Pelvic mass | Malignancy |
| Neurological signs | Cauda equina, MS |
6. Investigations
First-Line
| Test | Purpose |
|---|---|
| Urinalysis / MSU | Exclude UTI, haematuria |
| Bladder diary (3 days) | Document frequency, volumes, leakage |
| Post-void residual | Exclude retention |
Second-Line (Specialist)
| Test | Indication |
|---|---|
| Urodynamics | Confirm detrusor overactivity |
| Cystoscopy | Haematuria, recurrent UTI, suspected pathology |
| MRI spine | Neurological symptoms |
7. Management
Conservative (First-Line)
| Intervention | Details |
|---|---|
| Caffeine reduction | Coffee, tea, cola |
| Fluid modification | 1.5-2L/day, avoid excess |
| Weight loss | If overweight |
| Bladder training | Scheduled voiding, gradually increase intervals |
Bladder Training
- Goal: increase time between voids
- Start at current interval, gradually extend by 15-30 min
- Duration: 6 weeks minimum
Pharmacotherapy
| Drug | Class | Notes |
|---|---|---|
| Oxybutynin | Anticholinergic | Avoid in elderly (cognitive effects) |
| Solifenacin | Anticholinergic | Better tolerated |
| Tolterodine | Anticholinergic | Extended release preferred |
| Mirabegron | Beta-3 agonist | No anticholinergic SEs, watch BP |
| Combination | Anticholinergic + beta-3 | If monotherapy fails |
Anticholinergic Side Effects
- Dry mouth
- Constipation
- Blurred vision
- Cognitive impairment (elderly - avoid if possible)
Third-Line (Specialist)
| Treatment | Notes |
|---|---|
| Botox (OnabotulinumtoxinA) | Injection into detrusor, lasts 6-9 months |
| Sacral neuromodulation | Implanted stimulator |
| Percutaneous tibial nerve stimulation | Weekly sessions |
8. Complications
| Complication | Notes |
|---|---|
| Quality of life impairment | Social isolation, depression |
| Skin breakdown | Chronic moisture |
| Falls (elderly) | Rushing to toilet |
| UTI | Pad use, incomplete emptying |
| Anticholinergic side effects | Cognitive impairment, constipation |
9. Prognosis & Outcomes
| Factor | Outcome |
|---|---|
| Bladder training | 50-80% improvement |
| Anticholinergics | 60-70% improvement |
| Botox | Effective for refractory cases |
| Chronic condition | Often requires ongoing management |
10. Evidence & Guidelines
| Organisation | Key Points |
|---|---|
| NICE NG123 | Bladder training first, avoid oxybutynin in elderly |
| ICS | OAB definitions and terminology |
| EAU | Stepwise management approach |
11. Patient / Layperson Explanation
What is overactive bladder? It's when your bladder squeezes unexpectedly, giving you a sudden strong urge to pass urine. Sometimes this can cause leakage if you can't get to the toilet quickly.
What are the symptoms?
- Sudden urge to go ("I need to go NOW")
- Going to the toilet very often (more than 8 times a day)
- Getting up at night to go
- Sometimes not making it in time
What causes it? Usually, we don't know the exact cause. It can happen with age, after stroke, or with conditions like MS or Parkinson's.
How is it treated?
- Lifestyle changes: Reduce caffeine, bladder training (gradually holding on longer)
- Medication: Tablets that relax the bladder
- Specialist treatments: Botox injections into the bladder, nerve stimulation
Will it get better? Most people find significant improvement with treatment. It's a very common condition - you're not alone, and there's lots we can do to help.
12. References
- NICE NG123. Urinary incontinence and pelvic organ prolapse in women. 2019.
- Gormley EA, et al. AUA/SUFU Guideline on Overactive Bladder. J Urol. 2019.
- Abrams P, et al. ICS Standardization Report. Neurourol Urodyn. 2010.