Anatomy

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  Detrusor: “Bladder muscle”—smooth muscle; innervation is parasympathetic (muscarinic acetylcholine—M2, M3; contraction) and sympathetic (β3-adrenergic receptors; detrusor inhibition or relaxation) (Figure 5-1)

  
  
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  Urethral sphincter

  
  
  
  
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    Internal urethral sphincter (IUS): Smooth muscle; sympathetic (α1) innervation; muscarinic acetylcholine, α- and β-adrenergic receptors

    
    
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    External urethral sphincter (EUS): Striated muscle; somatic motor innervation via pudendal nerve (S2–S4); nicotinic acetylcholine receptors

    
    
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    Submucosal endovascular cushions

    
    
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    Surrounding tissue support—hammock hypothesis—the anterior vaginal wall with its attachment to the arcus tendineus of the pelvic fascia forms a hammock of tissue under the urethra and bladder neck that prevents urethral and bladder neck descent, such that the urethra compresses shut with increased intra-abdominal pressure

Physiology

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  Bladder filling = SYMPATHETIC = “STORAGE”

  
  
  
  
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    L1–L3 → lumbar sympathetic ganglia → forms hypogastric nerve to pelvis

    
    
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    Norepinephrine released → decreases smooth muscle tone in bladder

    
    
    
    
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      Relaxation of detrusor muscle: β3-adrenergic receptors in bladder stimulated (bladder fills)

      
      
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      Contraction of IUS: α-Adrenergic receptors in IUS stimulated (sphincter tightens)

      
      
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      Contraction of EUS by trained voluntary action (pudendal nerve originates from S2 to S4 to innervate EUS and perineal muscles—acetylcholine)

  
  
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  Micturition (emptying of bladder) = PARASYMPATHETIC = “PEEING”

  
  
  
  
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    Full bladder sensed by mechano-receptors in bladder

    
    
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    S2–S4 → sacral spinal cord → forms pelvic nerve

    
    
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    Stimulates bladder using acetylcholine and relaxes the urethra employing nitric oxide

    
    
    
    
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      Contraction of detrusor muscle: Muscarinic cholinergic (M3) receptors stimulated (bladder contracts)

      
      
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      Relaxation of IUS: M3 receptors stimulated (sphincter relaxes)

      
      
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      Relaxation of EUS by trained voluntary action (pudendal nerve originates from S2–S4—acetylcholine)

Definition

Involuntary loss of urine. Prevalence in the United States is about 50% of adult women.

Types

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  Stress urinary incontinence (SUI): Most common type (50–70% of UI)

  
  
  
  
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    Involuntary leakage during effort, exertion, sneezing, or coughing

    
    
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    Risk factors include age, parity, vaginal delivery

    
    
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    Leakage with stress test. Bladder capacity and post-void residual (PVR) normal (PVR generally considered normal if <150 cc or <1/3 void volume)

    
    
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    Urethral hypermobility (straining angle ≥30 degrees on Q-tip test) present in many women with SUI

    
    
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    Urodynamic SUI: During filling cystometry, involuntary urine leakage with increased intra-abdominal pressure and without detrusor contraction

  
  
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  Urge incontinence

  
  
  
  
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    Leakage accompanied by or immediately preceded by urge to void

    
    
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    Typically results from sudden, involuntary detrusor contractions

    
    
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    Usually idiopathic; but can be from inflammation/irritation, calculi, neurologic disorders, outlet obstruction, increased urine output

    
    
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    Urodynamics: If detrusor contractions are seen on urodynamics, it is called Detrusor Overactivity (DO). Detrusor instability; small capacity bladder, normal PVR

  
  
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  Mixed urinary incontinence

  
  
  
  
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    Combination of stress and urge incontinence

    
    
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    PVR within normal limits

    
    
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    Leakage with stress test, detrusor contractions on urodynamics

  
  
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  Functional incontinence (Table 5-1)

  
  
  
  
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    Associated with cognitive, psychological, or physical impairments that interfere with appropriate toileting. May be transient.

  
  
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  Structural incontinence (Table 5-1)

Definitions of Lower Urinary Tract Symptoms (LUTS)

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  Urgency: Complaint of sudden desire to pass urine, with or without urge urinary incontinence

  
  
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  Frequency: The complaint of voiding too often (more than seven times in waking hours)

  
  
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  Nocturia: The complaint of arousal from sleep to void one or more times per night

  
  
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  Nocturnal enuresis: The complaint of urinary incontinence during sleep

  
  
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  The term “overflow incontinence” is not recommended by the International Continence Society (ICS)

Workup of Urinary Incontinence

Basic Evaluation

History

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  Frequency/amount of leakage, precipitating factors, impact of leakage on daily life, pad use, linkage to temporal events (childbirth, trauma, new medication, surgery, radiation therapy, medical conditions—eg, bronchitis, asthma), precipitants (eg, medications, caffeinated beverages, alcohol, physical activity, coughing, laughing, sound of water, placing hands in water), pelvic bulge/pressure, urinary urgency or frequency, nocturia, hematuria, recurrent UTIs, voiding problems, incontinence, defecating problems, effort maneuvers, interrupted voiding, incomplete emptying, straining to empty, bowel and sexual function (voiding, bowel control, and sexual function share sacral cord innervation; anal incontinence is more common in people with urinary incontinence). Urinary diary may be helpful (24 hours to 3 days)

Physical Examination

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  Pelvic examination: For masses, pelvic organ prolapse (POP), vaginal atrophy

  
  
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  Cough stress test: Ask patient to cough and look for leakage

  
  
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  Palpate pelvic floor muscles (levator ani) for symmetry and bulk, and ability to voluntarily contract muscles

  
  
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  Cotton swab test: Test of urethral hypermobility; place Q-tip in to level of vesical neck, measure change in axis with straining; >30 degrees is urethral hypermobility

  
  
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  Pelvic Organ Prolapse Quantification System (POP-Q), Figure 5-4

  
  
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  Neurologic tests—The sacral reflexes (anal reflex and the bulbocavernosus reflex) should be assessed (pudendal nerve S2–S4). Anal reflex: stroke skin adjacent to anus; causes contraction of external anal sphincter. Bulbocavernosus reflex: tap or squeeze clitoris; causes contraction of the bulbocavernosus muscle and/or external anal sphincter

  
  
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  Post-void residual volume: Passive or active; goal about 150 cc and <1/3 volume

  
  
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  Lab tests: Urinalysis, urine culture, renal function tests, glucose, calcium

Further Evaluation

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  Urodynamic testing: Combination of tests that involves simultaneous measurement of various physiologic parameters or urethral and bladder function during bladder filling and emptying

  
  
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  Cystourethroscopy

Definition

Involuntary leakage during effort, exertion, sneezing, or coughing

Pathophysiology

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  Leakage from urethra occurs when intravesical pressure exceeds urethral pressure

  
  
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  Factors that affect urethral pressure: Bladder neck position, urethral sphincter muscle and nerve integrity, urethral smooth muscle and vascular plexuses, and surrounding tissue support

Mechanisms

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  Urethral hypermobility: Poor urethral support; shown clinically by documenting movement of anterior vaginal wall during straining

  
  
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  Intrinsic sphincter deficiency: Low-pressure urethra resulting from neurologic disease, radiation, scarring

Treatment

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  Lifestyle Interventions: Weight loss, decreasing caffeine intake

  
  
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  Pelvic Floor Muscle Training: Kegel exercises

  
  
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  Medication: Goal to increase urinary sphincter tone

  
  
  
  
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    Imipramine 10–20 mg orally once daily to four times daily

  
  
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  Devices: Pessaries and urethral inserts

  
  
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  Surgery

  
  
  
  
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    Stabilize the urethra to prevent descent with increased abdominal pressure

    
    
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    Create a stable supportive layer for urethral compression

Surgical Approaches for SUI

Retropubic Suspension

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  Marshall–Marchetti–Krantz (MMK) vesicourethral suspension

  
  
  
  
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    Sutures placed on each side of urethra through pubocervical fascia and fixed to periosteum of posterior pubic symphysis, suspending the fascia

    
    
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    Risk of periostitis and osteitis pubis

  
  
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  Burch Retropubic Urethropexy (Figure 5-2)

  
  
  
  
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    Endopelvic fibromuscular tissue adjacent to mid and proximal urethra is attached to pectineal (Cooper’s) ligaments on posterior surface of superior pubic ramus (rather than the periosteum of the pubic symphysis)

  
  
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  Similar cure rates: 80–90% (1 year); 70–90% (5 years); >70% (10 years)