Urinary Incontinence

• Urinary incontinence is the involuntary loss of urine
• Stress (urinary) incontinence


  Involuntary urine loss on effort or physical exertion (e.g., sporting activities), or on sneezing or coughing
• Urgency (urinary) incontinence


  Involuntary loss of urine associated with urgency, that may be associated with detrusor overactivity
• Mixed (urinary) incontinence


  Involuntary loss of urine associated with urgency and also with effort or physical exertion or on sneezing or coughing
• Overflow (urinary) incontinence


  Loss of urine due to poor or absent bladder contractions or bladder outlet obstruction that leads to urinary retention with overdistention of the bladder and overflow incontinence
• Continuous (urinary) incontinence secondary to urinary fistula

  Loss of urine through a urinary fistula secondary to surgery, radiation, or obstructed labor
• Functional (urinary) incontinence


  Loss of urine due to a physical or psychological (e.g., dementia) inability to respond to voiding cues. Often seen in nursing home patients and geriatric patients
• Types of urinary incontinence

  • Stress (urinary) incontinence
  • Urgency (urinary) incontinence
  • Mixed (urinary) incontinence
  • Overflow (urinary) incontinence
  • Continuous (urinary) incontinence secondary to urinary fistula
  • Functional (urinary) incontinence
• The annual incidence of stress incontinence is estimated to be 4% to 11% and the annual remission rates have been reported as 4% to 5%
• Urgency incontinence occurs in 5% to 10% of women at least monthly
• Risk factors for urinary incontinence

  • Age
  • Obesity
  • Diabetes mellitus
  • Pregnancy and vaginal delivery
  • Genetics
  • Hormonal status
  • Pelvic surgery
  • Smoking
  • Chronic cough
  • Medications
• Stress incontinence


  • More predominant in younger and middle-aged women
• Urgency incontinence and mixed incontinence

  • More predominant in older women
• In postmenopausal women, low estrogen levels may contribute to urinary incontinence
• Treatment with local (vaginal) estrogen was shown to improve symptoms, whereas oral hormone replacement therapy worsened symptoms
• Obesity has been shown to be a significant risk factor for urinary incontinence, with a greater impact on stress incontinence compared with urgency and mixed incontinence
• Type 2 diabetes mellitus is a strong independent risk factor for urinary incontinence, particularly urgency incontinence
• Risk factors for stress urinary incontinence

  • Age
  • Obesity
  • Diabetes mellitus
  • Pregnancy and vaginal delivery
  • Genetics
  • Hormonal status
  • Pelvic surgery
  • Smoking
  • Chronic cough
  • Medications
• Urinary continence at rest

  Intra-urethral pressure exceeds the intravesical pressure
• Mechanisms for maintaining continence at rest


  • Continuous contraction of the internal sphincter
  • External sphincter provides about 50% of urethral resistance and is the second line of defense against incontinence
  • Urethral submucosa vasculature filling with blood increases intraurethral pressure
• Micturition


  1. Bladder releases its contents under voluntary control through a series of coordinated activities, resulting in urethral relaxation and bladder contraction

  2. Stretch receptors in the bladder wall send a signal to the CNS to begin voluntary voiding

  3. Inhibition of the sympathetic sacral and pudendal nerves causes relaxation of the urethra, external sphincter, and levator ani muscles

  4. Activation of the parasympathetic pelvic nerve results in contraction of the detrusor muscle, and micturition begins
• Neurologic control of the bladder and urethra is provided by both the autonomic (sympathetic and parasympathetic) and somatic nervous systems
• The sympathetic nervous system provides continence and prevents micturition by contracting the bladder neck and internal sphincter
• The parasympathetic nervous system allows micturition to occur
• The somatic nervous system aids in voluntary prevention of micturition by innervating the striated muscle of the external sphincter and pelvic floor through the pudendal nerve
• Components of the physical examination for urinary incontinence

  • Internal pelvic examination
  • External pelvic examination
  • Evaluation of pelvic organ prolapse
  • Neurologic examination (deep tendon reflexes, anal reflex, pelvic floor contractions, bulbocavernosus reflex)
• Diagnostic tests for urinary incontinence

  • Voiding diary or bladder chart
  • Urinalysis and urine culture
  • Stress test
  • Postvoid residual
  • Cotton swab test
  • Cystometrogram
  • Uroflowmetry
  • Urodynamic studies
• Stress test


  Filling the bladder with up to 300 mL of normal saline or sterile water through a catheter, then asking the patient to cough while the clinician observes for urine leakage
• Cotton swab test


  Inserting a lubricated cotton swab into the urethra to the angle of the urethrovesical junction, then having the patient strain as if urinating to observe the movement of the cotton swab
• The upper limits of a normal postvoid residual have been reported as 50 to 100 mL
• Stress incontinence test


  1. Clinician inserts lubricated cotton swab into urethra to angle of urethrovesical junction

  2. Patient strains as if urinating

  3. Urethrovesical junction descends and cotton swab moves upward

  4. Change in cotton swab angle normally less than 30 degrees

  5. Change greater than 30 degrees consistent with hypermobile urethra
• Urodynamics


  • Functional study of lower urinary tract
  • Usually reserved for patients contemplating surgery or unclear diagnosis
• Urodynamic studies


  1. Evaluation of urethral function (urethrocystometry, urethral pressure profilometry)

  2. Bladder filling (cystometry)

  3. Bladder emptying (uroflowmetry and voiding cystometry or pressure flow studies)
• Cystometry


  Measures pressure and volume relationship of bladder during filling and/or pressure flow study during voiding
• Normal bladder capacity


  • 400 to 600 mL
• Uroflowmetry


  Measures rate of urine flow and flow time through urethra when patient spontaneously voids
• Uroflowmetry


  • Useful in diagnosing outflow obstruction and abnormal bladder reflexes
• Voiding diary demonstrates urinary frequency, nocturia, urge incontinence, and greater consumption of fluid, caffeine, and alcohol in the evening
• Stress incontinence


  Involuntary loss of urine through intact urethra in response to increase in intra-abdominal pressure
• Causes of stress incontinence

  • Hypermobile urethra
  • Weakness in internal urethral sphincter (intrinsic sphincter deficiency)