What is the difference between urge and stress incontinence?

Differences Between Urge and Stress Urinary Incontinence

Stress urinary incontinence (SUI) and urge urinary incontinence (UUI) are fundamentally different conditions with distinct pathophysiology, symptoms, and treatment approaches.

Key Differences

Defining Characteristics

• Stress Urinary Incontinence (SUI):

  • Involuntary leakage of urine during activities that increase abdominal pressure
  • Occurs during sneezing, coughing, physical exercise, lifting, bending, or changing positions 1
  • No preceding sensation of urgency
  • Related to urethral sphincter failure associated with intra-abdominal pressure 1

• Urge Urinary Incontinence (UUI):

  • Involuntary leakage accompanied by or immediately preceded by urgency 1
  • Characterized by a sudden, compelling desire to pass urine 1
  • Often associated with overactive bladder syndrome
  • Typically occurs when trying to reach the toilet after feeling urgency 2

Pathophysiology

• SUI:

  • Anatomical issue with urethral support or intrinsic sphincter deficiency
  • Results from inability to maintain urethral closure against increased abdominal pressure
  • Associated with pelvic floor weakness, often from childbirth trauma or aging 1

• UUI:

  • Traditionally considered a neurological dysfunction of the bladder 2
  • May involve detrusor overactivity
  • Recent evidence suggests anatomical instability at the bladder outlet may also play a role 2

Timing and Triggers

• SUI:

  • Occurs immediately with physical exertion
  • No warning sensation before leakage
  • Typically stops when physical exertion ceases

• UUI:

  • Preceded by a strong urge to urinate
  • Often occurs when changing positions (96% when getting up from sitting position) 2
  • May wake patients at night with urgency

Clinical Assessment

A simple clinical assessment can help distinguish between types:

1. Key questions to differentiate:

   • "Do you leak urine when you cough, laugh, sneeze, or exercise?" (SUI)
   • "Do you leak urine when you have a strong, sudden urge to urinate?" (UUI)
   • "When exactly do you lose urine after feeling urgency?" 2, 3

2. Physical examination:

   • Cough stress test (positive in SUI)
   • Assessment for pelvic organ prolapse (associated with SUI)
   • Post-void residual measurement 4, 5

Treatment Approaches

• SUI Treatment:

  • First-line: Pelvic floor muscle training (PFMT) for at least three months 6
  • Weight loss and exercise for obese women 1
  • Surgical options: midurethral synthetic slings, urethral bulking agents, Burch colposuspension 6

• UUI Treatment:

  • Behavioral therapy including bladder training
  • Pharmacologic therapy (e.g., tolterodine) for overactive bladder symptoms 7
  • Avoid systemic pharmacologic therapy for SUI 6

Mixed Urinary Incontinence

• Combination of both SUI and UUI symptoms 1, 8
• Treatment typically addresses the most bothersome component first
• Combined approach of PFMT with bladder training is recommended 6

Clinical Pearls

• The 3 Incontinence Questions (3IQ) questionnaire has acceptable accuracy for classifying urge and stress incontinence in primary care settings (sensitivity 0.75 for UUI, 0.86 for SUI) 3
• Persistent urgency after anti-incontinence surgery reduces patient satisfaction and overall continence 8
• 96% of patients with UUI lose urine when getting up from a sitting position on their way to the toilet 2
• Urodynamic testing is not required before initiating conservative treatment but may be needed before surgical intervention 4, 5

Understanding these differences is crucial for proper diagnosis and treatment selection, as the management approaches differ significantly between these two conditions.