Overview
Urinary Incontinence
1. Clinical Overview
Summary
Urinary Incontinence (UI) is the involuntary leakage of urine. It is a highly prevalent condition affecting physical, psychological, and social well-being. The two main subtypes are Stress Urinary Incontinence (SUI), caused by urethral sphincter incompetence during increased intra-abdominal pressure, and Urge Urinary Incontinence (UUI), driven by detrusor overactivity (Overactive Bladder Syndrome). Many patients exhibit Mixed UI. Diagnosis relies on history and a bladder diary. Initial management is conservative (lifestyle, pelvic floor training, bladder retraining), escalating to pharmacotherapy (anticholinergics/beta-3 agonists) for UUI and surgery for SUI. The use of vaginal mesh for SUI is currently restricted in many jurisdictions due to safety concerns. [1,2]
Key Facts
- Prevalence: Affects ~40% of women and ~10% of men.
- Stress UI (SUI): Leakage on effort or exertion (cough, sneeze, lift). Pathology: Pelvic floor weakness / Urethral hypermobility.
- Urge UI (UUI): Leakage accompanied by or immediately preceded by urgency. Pathology: Detrusor Overactivity.
- Overactive Bladder (OAB): Urgency +/- Incontinence, usually with frequency and nocturia.
- Overflow Incontinence: Leakage from a full, distended bladder (Chronic Retention). Paradoxical "dribbling".
Clinical Pearls
The "Key in the Door" Sign: Pathognomonic for Urge Incontinence. The patient gets a sudden, overwhelming urge to void as soon as they put their key in the front door (conditioned reflex).
Caffeine is a Diuretic AND Irritant: It stimulates the detrusor muscle directly. Cutting caffeine is the single most effective lifestyle intervention for OAB.
Exclude Infection: ALWAYS dip urine first. A UTI can mimic Urge Incontinence perfectly. Do not start anticholinergics without ruling out infection.
Estrogen Deficiency: In post-menopausal women, vaginal atrophy ("Genitourinary Syndrome of Menopause") contributes significantly to urgency and frequency. Topical estrogen can help.
2. Epidemiology
Risk Factors
- Female Gender: Anatomy, Childbirth (vaginal delivery), Menopause.
- Age: Prevalence increases with age.
- Obesity: Increases intra-abdominal pressure (worsens SUI).
- Previous Pelvic Surgery: Hysterectomy, Prostatectomy (in men).
- Smoking: Chronic cough worsens SUI; irritants worsen UUI.
- Comorbidities: Diabetes, Stroke, Parkinson's (UUI).
3. Pathophysiology
Physiological Mechanisms
-
Stress Urinary Incontinence (SUI):
- Failure of the sphincter mechanism to remain closed when intra-abdominal pressure rises.
- Causes: Weakness of pelvic floor muscles (levator ani) or connective tissue laxity (urethral hypermobility).
-
Urge Urinary Incontinence (UUI):
- Detrusor Overactivity (DO): Involuntary contractions of the detrusor muscle during the filling phase.
- Neurogenic (e.g., MS, Spinal cord) or Idiopathic.
-
Overflow Incontinence:
- Bladder outlet obstruction (BPH) or Detrusor Underactivity (Diabetes/Neuro).
- Bladder pressure > Urethral pressure only when bladder is over-full.
4. Clinical Presentation
Distinguishing Types
| Symptom | Stress UI | Urge UI |
|---|---|---|
| Trigger | Cough, sneeze, jump, lift | Sudden urge, running water, "key in door" |
| Leak Volume | Small squirt | Moderate to large (full void) |
| Nocturia | Rare | Common |
| Warning | None | Seconds to minutes |
| Frequency | Normal | Increased (>8/day) |
(Mixed UI presents with features of both).
Impact
Social isolation ("Toilet mapping").
Common presentation.
Depression.
Common presentation.
Falls (fractures) in elderly rushing to toilet at night.
Common presentation.
Skin breakdown (Incontinence Associated Dermatitis).
Common presentation.
5. Clinical Examination
Assessment
- Abdomen: Palpate for distended bladder (Overflow).
- Vaginal Exam:
- Assessment of atrophy (pale, dry mucosa).
- Prolapse assessment (POP-Q).
- Cough Stress Test: Ask patient to cough with full bladder. Observe leakage.
- Pelvic Floor Muscle strength grading (Oxford scale 0-5).
- Digital Rectal Exam: Prostate size (men), anal tone (Sacral roots S2-S4).
6. Investigations
Primary Care
- Urinalysis: Rule out UTI, Glycosuria (Diabetes), Haematuria.
- Bladder Diary (3 days): Gold standard for assessment. Records input, output, and leakage episodes.
- SUI: Normal volumes, leak with activity.
- UUI: Small Frequent voids, urgency leaks.
- Post-Void Residual (PVR): Bladder scan.
- less than 50ml: Normal.
- >100-200ml: Potential retention/overflow. Avoid anticholinergics.
Specialist
- Urodynamics (Cystometry):
- Measures pressures during filling and voiding.
- Defines Detrusor Overactivity vs Sphincter Incompetence.
- Essential before surgery to predict outcomes.
- Cystoscopy: To rule out bladder cancer/stones if haematuria or pain.
7. Management
Management Algorithm
TYPE OF INCONTINENCE
↓
┌───────────┴───────────┐
↓ ↓ ↓
STRESS UI MIXED UI URGE UI
↓ ↓ ↓
LIFESTYLE TREAT MOST LIFESTYLE
(Weight, BATHERSOME (Caffeine,
Smoking) FIRST Fluid mgmt)
↓ ↓
PELVIC FLOOR BLADDER
MUSCLE TRAINING RETRAINING
(3 months) (6 weeks)
↓ ↓
SURGERY REFERRAL PHARMACOTHERAPY
(or Duloxetine) (Anticholinergic
or Beta-3)
↓
Resistant?
BOTOX / NEURO
MODULATION
General Lifestyle Measures (All types)
- Weight Loss: BMI >30 reduction improves SUI significantly.
- Fluid Management: Normalise intake (1.5-2L). Avoid caffeine/alcohol.
- Stop Smoking.
Management of Stress UI
- Pelvic Floor Muscle Training (PFMT): First line. Supervised (physio). 3 sets of 8 contractions, 3 times/day for >3 months. Cure/Improvement in 50-70%.
- Pharmacotherapy:
- Duloxetine: SNRI. Increases sphincter tone. Nausea is common. Second line if surgery contraindicated.
- Surgery (If PFMT fails):
- Urethral Bulking Agents: Injection into urethra. Low risk, lower durability.
- Colposuspension (Burch): Open/Laparoscopic hitch for bladder neck.
- Autologous Facial Sling: Patient's own fascia.
- Mid-urethral Tape (Mesh): Note: Use of synthetic mesh is restricted/paused in UK/many nations due to complications.
Management of Urge UI / OAB
- Bladder Retraining: "Holding on" techniques to increase interval between voids. Minimum 6 weeks.
- Pharmacotherapy:
- Anticholinergics (e.g., Solifenacin, Tolterodine, Oxybutynin).
- Warning: Anticholinergic burden in elderly (Confusion/Dementia risk). Avoid Modified Release Oxybutynin in elderly.
- Beta-3 Agonists (Mirabegron).
- Relaxes detrusor. No cognitive side effects. Contraindicated in severe uncontrolled hypertension.
- Anticholinergics (e.g., Solifenacin, Tolterodine, Oxybutynin).
- Vaginal Estrogen: If atrophy present.
- Specialist procedures:
- Intravesical Botox: Injections into detrusor. Risk of urinary retention (patient must be willing to self-catheterise). Repeated every 6-9 months.
- Sacral Neuromodulation (SNS): Pacemaker for the bladder.
- Percutaneous Tibial Nerve Stimulation (PTNS).
8. Complications
- Incontinence Associated Dermatitis: Urinary burns, fungal infection.
- Social Isolation: Impact on employment and relationships.
- Falls: Fractured neck of femur (associated with nocturia).
- Catheter complications: In overflow incontinence.
9. Prognosis and Outcomes
- SUI: Surgery has high success rates (80-90%), but recurrence occurs over 10-20 years.
- UUI: Often a chronic condition managed rather than cured. Pharmacotherapy persistence is low due to side effects.
10. Evidence and Guidelines
Key Guidelines
| Guideline | Organisation | Key Recommendations |
|---|---|---|
| NG123 | NICE (2019) | PFMT first line for SUI. Bladder training first line for UUI. Caution with vaginal mesh. |
| OAB Guidelines | EAU | Mirabegron as alternative to anticholinergics. |
| Mesh Safety | Cumberlege Report | Major restrictions on synthetic mesh due to erosion/pain risks. |
Landmark Studies
1. The ABC Trial (2012)
- Comparison: Anticholinergic vs Botox for OAB.
- Result: Botox slightly superior for symptom reduction but higher risk of UTI and retention.
2. ESTHER Trial
- Topic: Anticholinergics in elderly.
- Result: High cognitive burden. Strong recommendation to avoid Oxybutynin in frailty.
11. Patient and Layperson Explanation
Why am I leaking?
- Stress Leak: The muscles closing your bladder (the tap) are weak. When you cough, the pressure inside is stronger than the muscle, and urine squirts out.
- Urge Leak: The bladder muscle (the tank) is twitchy. It squeezes when it shouldn't, giving you a sudden desperate need to go that you can't control.
Stress Incontinence Treatment
- Physiotherapy: Exercises to strengthen the pelvic floor muscles act like tightening the tap. You must do them intensively for 3 months to see results.
- Surgery: If exercises don't work, an operation can support the urethra (like a hammock) to stop leaks.
Urge Incontinence Treatment
- Training: We teach the bladder to hold more urine and be less twitchy.
- Tablets: Medicines can relax the bladder muscle.
- Botox: Just like for wrinkles, Botox relaxes the bladder muscle if injections are used.
12. References
Primary Sources
- NICE Guideline NG123. Urinary incontinence and pelvic organ prolapse in women: management. 2019.
- Abrams P, et al. Incontinence. 6th International Consultation on Incontinence. 2017.
- Nambiar AK, et al. EAU Guidelines on Assessment and Nonsurgical Management of Urinary Incontinence. Eur Urol. 2018;73:596-609.
- Independent Medicines and Medical Devices Safety Review (The Cumberlege Report). First Do No Harm. 2020.
13. Examination Focus
Common Exam Questions
- Gynaecology: "Treatment for Mixed Incontinence?"
- Answer: Treat the most bothersome symptom first. Usually bladder retraining (Urge) then PFMT (Stress).
- Pharmacology: "Side effects of Oxybutynin?"
- Answer: Dry mouth, dry eyes, constipation, confusion (anticholinergic).
- Urology: "Mechanism of Mirabegron?"
- Answer: Beta-3 adrenergic receptor agonist (relaxes detrusor).
- Geriatrics: "Elderly woman with new incontinence + confusion. First test?"
- Answer: Urine Dip (Rule out UTI).
Viva Points
- Mesh Scandal: Why was it stopped? Erosion into vagina/urethra causing chronic pain and dyspareunia.
- Overflow Incontinence: How to spot it? Dribbling, paradoxical nocturnal leakage, palpable bladder. Do NOT give anticholinergics (will cause acute retention).
Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Clinical decisions should account for individual patient circumstances. Always consult appropriate specialists.