Functional: Urinary Incontinence

See 2017 AUA Female SUI Guideline Notes, 2019 AUA Incontinence after Prostate Therapy Guideline Notes 2017 CUA OAB Guideline Notes, and 2019 AUA OAB Guidelines

Physiology of Urinary Continence

• Urinary continence is maintained during elevations in abdominal pressure by
  1. Passive transmission of abdominal pressure to the proximal urethra presses the anterior wall against the posterior wall
  2. A “guarding” reflex involving an active contraction of striated muscle of the external urinary sphincter can transiently help continence
• Male Sphincteric Mechanisms
  • Internal sphincter
    • Extends from the bladder neck to the distal verumontanum
    • Contributes to continence
  • External sphincter
    • Loss of external sphincter function, such as with traumatic pelvic injury, may not result in incontinence in men with an intact bladder neck. This is in contradistinction to the bladder neck in women, which is relatively weak, making women more vulnerable to incontinence with any deficiency of external sphincter function.
• Female Sphincteric Mechanisms
  • Female urethra
    • Composed of four layers, with the middle muscular layer maintaining the resting urethral closure mechanism and the outer seromuscular layer augmenting this closing pressure.
  • The levator ani, urethropelvic ligament, and pubocervical fascia provide support to the bladder neck and underside of the bladder. The round ligament provides support to the uterus.
  • Unlike the powerful continence zone created at the level of the bladder neck in men, continence in women is largely a result of the bulk of the muscle along the proximal urethra and/or midurethra responsible for sphincteric control.
    • Muscular forces (primarily striated muscle) create a nearly complete circumferential compression of the midurethra under the influence of tonic pudendal innervation.
  • Fixation of the urethra by ligamentous support (pubourethral ligaments) normally minimizes movement of the proximal urethra, further contributing to continence by helping to prevent abdominal forces to be transmitted to the remainder of the urethra.
  • It is the combined effect of these extraurethral forces, intrinsic urethral properties, and muscular elements that promotes continence, and loss of any one, or several in most cases, can result in UI in women.

Types of Urinary Incontinence

1. Stress urinary incontinence (SUI)
   • Occurs when the intra-abdominal pressure exceeds the intraurethral pressure
   • More common in females; usually occurs in males only after a prostatectomy in which the external urethral sphincter is damaged
2. Urgency urinary incontinence (UUI)
   • Involuntary leakage of urine, accompanied or immediately preceded by urgency
3. Mixed urinary incontinence (MUI)
   • Complaint of involuntary leakage associated with urgency and with exertion, effort, sneezing, or coughing. Thus in MUI, both SUI and urgency incontinence (“OAB wet”) are present in the same person.
     • A person with SUI and “OAB dry” does not have MUI
   • Management should be aimed at the most bothersome symptoms
4. Continuous urinary incontinence
5. Nocturnal Enuresis
   • Definition of nocturnal enuresis: the complaint of involuntary urinary loss of urine that occurs during sleep
     • Differentiated from nocturia which is intentionally getting out of bed to pass urine at night and is preceded and followed by sleep
   • An important symptom, especially in males, as it may indicate that these males are in high-pressure chronic urinary retention, which is usually associated with upper tract dilation and the risk of renal failure.
   • Nocturnal enuresis, without residual urine, may be related to the overactive bladder. This can be treated with antimuscarinics and potentially with desmopressin in the melt formulation.
6. Postmicturition leakage or dribble
7. Insensible urinary incontinence
   • Urethral diverticula (typically postvoid urine loss), ectopic ureter in females (typically continuous urine loss), and overflow incontinence (typically small-volume frequent urine loss, urinary frequency, and small volume voids) should be considered
8. Other (coital incontinence, giggle incontinence)

Epidemiology of Urinary Incontinence

• Females
  • Prevalence 25-40%
  • Prevalence rates of stress urinary incontinence tend to be higher (10-25%) than either urge urinary incontinence (3-10%) or MUI (5-20%)
• Males
  • Prevalence in older males 11-34%, considerably lower than the rate found in females
  • Stress urinary incontinence is uncommon in males, except in men who have previously undergone radical pelvic surgery (radical prostatectomy or abdominoperinal resection), previous TURP, or who have a neurologic condition that may predispose them to SUI.
  • Urge urinary incontinence and MUI are more common in males than stress urinary incontinence, and in many cases these may be attributable to BOO from BPH, other outlet disorders, OAB, or other inflammatory or infectious processes.
  • Remission rates for UI are considerably higher in males than females

Pathophysiology of SUI in Females

• Original theories explaining the pathophysiology of UI in women focused on the descent of the proximal urethra and bladder neck. It was believed that as the urethra became hypermobile, intraperitoneal forces could no longer constrict the urethra and incontinence resulted.
• Posterior musculofascial fascial/ligamentous support of the urethra from the anterior vaginal wall and extending laterally from the vagina to the levator ani and arcus tendineus fascia pelvis contribute to the maintenance of continence seen at times of increases in intraabdominal pressure.
• It is compression of the urethra against this firm posterior backing (hammock) that enables the urethra to prevent urinary loss with stress maneuvers. Loss of backing from this musculofascial support leads to incontinence because of an inability to compress the urethra.
• This theory suggests that repositioning the urethra, previously considered to be essential, is not necessarily essential to restoring continence in females who leak with SUI. The essential element to restoring continence rests with restoring the layer of support to the posterior urethra and therefore allowing the urethra to be compressed adequately.
• Intrinsic Sphincteric Deficiency
  • Some women with no hypermobility have fairly severe SUI which is the concept of intrinsic sphincteric deficiency
  • Patients with ISD have classically been described as having a “pipe stem” urethra, meaning a fixed urethra with little intrinsic closure function. This finding may result from previous surgery and is typically iatrogenic in some way.
  • Subtler forms of ISD, which typically coexist with the finding of urethral hypermobility, are more commonly found and are likely responsible for most forms of SUI.
    • ISD in this setting may be secondary to ischemic injury (birth or other trauma) or other forms of progressive pudendal nerve damage.
  • ISD was historically identified urodynamically using the concept of abdominal leak point pressure (ALPP).
    • ALPP testing describes the abdominal pressure required to cause urethral incontinence.
    • Low ALPP (< 60 cm water) has been associated with ISD.
  • Most forms of SUI likely involve some degree of ISD, even if urethral hypermobility is present.
    • Even among patients with hypermobility, treatments such as pubovaginal sling, midurethral sling, and even bulking agents appear to have reasonable efficacy.
  • However, the reverse is untrue— treatments aimed specifically at the correction of hypermobility may be less helpful in the presence of severe ISD and limited mobility.
    • Burch colposuspension and various needle suspension procedures, for example, have limited usefulness in the treatment of ISD, particularly in the setting of a fixed urethra.

Risk factors for Urinary Incontinence

• Males and Females
  1. Age
     • Age is the strongest risk factor for UI in men
  2. Pelvic floor disorders (e.g. fecal incontinence)
  3. Neurologic disease
• Females
  1. Race/Ethnicity
     • Caucasian women have an increased prevalence of UI and an increased risk of developing incident UI/SUI when compared to African-American women and Asian women.
     • One group has noted higher urethral closing pressures in African-American women.
     • Rates of seeking treatment for urinary incontinence are similar between African-Americans and Caucasians
  2. Pregnancy
     • Prevalence of urinary incontinence, particularly SUI, increases during pregnancy and in general increases with gestational age.
       • Overall, prevalence of SUI during pregnancy is ≈40%.
     • Pelvic floor muscle training can reduce the risk of UI during pregnancy and postpartum, if also performed after delivery
     • Development of UI during pregnancy reflects greater risk of developing UI later in life
     • Any history of vaginal birth of a large baby with increased birth weight has been associated with an increased likelihood for developing UI
       • Cesarean delivery confers an advantage over normal spontaneous vaginal delivery for UI and SUI
     • Increasing parity is associated with increased risk of UI
  3. Obesity
     • All types of UI have been associated with the development of obesity in women
       • BMI > 30 has been shown to more than double a women’s risk of UI
     • Whereas symptomatic SUI appears to be more severe and more common in obese women, abdominal leak point pressure values are higher in obese women who are considering surgery for SUI, indicating gradual accommodation of the pelvic floor in women with SUI.
  4. Females living in long-term care facilities
  5. Smoking
  6. Diabetes
  7. Estrogen
     • Oral estrogen (with or without progestogens) is associated with increased risk of UI in middle-aged and older women
     • Topical estrogen is not associated with risk of SUI, and it has proven its efficacy in treating women with vaginal atrophy and recurrent UTIs
  8. Diet
     • Caffeine intake associated with symptoms of urgency incontinence, mixed incontinence, and OAB. No clear association exists with SUI
     • Carbonated beverages and artificial sweeteners have also been associated with urgency symptoms, though confirmatory studies are lacking
  9. Depression

Causes of Transient Incontinence (DIAPPERS)

• Delirium
• Infection (UTI)
• Atrophic vaginitis/urethritis
• Psychological (e.g. severe depression, neurosis)
• Pharmacologic
• Excess urine production
• Restricted mobility
• Stool impaction

Diagnosis and Evaluation of Urinary Incontinence

• History and Physical Exam
  • History
    • Characterize incontinence (subjectively, quantify leakage, duration of symptoms, any inciting events that contributed to the onset of leakage, impact on daily life and activities)
    • Voiding pattern should be defined
    • Treatment expectations and an understanding of the balance between benefits and risks/burden of available treatment options.
    • Females
      • Regarding pelvic prolapse specifically, focus on whether the patient is aware of any prolapse and what, if any, symptomatology and bother the prolapse may be causing.
      • Gynecologic and obstetric history, including gravity, parity, and hormonal status.
      • Determination of whether the patient is premenopausal, perimenopausal, or post-menopausal and whether she has used any exogenous hormones such as oral contraceptives or local or systemic hormone replacement therapy
  • Physical examination
    • Body habitus (BMI)
    • Females
      • External genitalia: general appearance, estrogen status, lesions, and labial size, and adhesions.
        • Attention to the overall tissue appearance and color is important. Hormonally deficient vaginal tissue has a pale, flat, dry appearance with no rugae, as opposed to the healthy, pink rugated tissue of well-estrogenized tissue
        • Estrogen status can be evaluated based on the presence or absence of a urethral caruncle, urethral prolapse, and/or labial adhesions, all of which, if present, may indicate estrogen deficiency.
      • Urethral position and mobility
        • Should be assessed at rest and with straining and coughing.
        • The Q-tip test was developed to objectify the evaluation of urethral mobility.
          • With the patient in the lithotomy position, a Q-tip is inserted into bladder through the urethra and the angle that the Q-tip moves from horizontal to its final position with straining is measured.
          • Hypermobility is defined as a Q-tip angle of > 30° from horizontal.
      • Assessment of prolapse
        • Ideally, should be performed in both the lithotomy and standing position.
    • Anal sphincter tone, which is a reflection of the function at S2-4, is particularly important in neurologic patients with pelvic floor dysfunction.
• Laboratory:
  • Urinalysis
  • Optional: PSA, blood tests (eg. urea and electrolytes)
• Imaging
  • Standard imaging studies are not necessary in the initial evaluation of uncomplicated incontinence.
    • Upper and lower urinary tract imaging in patients in whom renal damage or pelvic pathologic conditions are suspected should be performed.
  • Voiding cystourethrogram (VCUG)
    • Optional in patients with recurrent UTIs, but can be helpful in the diagnosis of a urethral diverticulum or VUR.
  • MRI
    • Has been proposed as an ideal method by which to evaluate the anatomy of the bladder neck and urethra with good correlation with functional studies.
    • Has also been advocated for evaluation of pelvic floor relaxation and pelvic organ prolapse.
• Other
  • Circumstances that warrant consideration of supplemental evaluation:
    • Inability to establish a diagnosis based on the patient’s symptoms and initial evaluation
    • Concomitant overactive bladder symptoms
    • Prior lower urinary tract surgery including anti-incontinence surgery
    • Known or suspected neurogenic bladder
    • Negative stress test
    • Abnormal urinalysis (e.g. unexplained hematuria or pyruia)
    • Elevated postvoid residual
    • High-grade (stage ≥3) pelvic prolapse
    • Evidence of dysfunctional voiding
  • Symptom quantification instruments
    • Voiding diaries can provide both diagnostic and therapeutic advantages.
      • The use of diaries often helps patients realized their pattern of urination and is more accurate than recall. Furthermore, the diary can provide patients with insights into those behaviors that can be altered to decrease urinary frequency.
    • 3-day voiding diary offers the same information as a 7-day one without being too exhaustive for patients
  • Questionnaires
    • Several validated questionnaires exist, including the International Consultation on Incontinence questionnaire short form (ICIQ-SF).
    • Both the voiding diary and the quality of life questionnaire not only help in the assessment of patients but also help in looking at treatment effects if repeated after the same patient has been treated
  • Postvoid residual
    • No established volumes that define normal or impaired emptying
  • Cystoscopy
    • Routine cystoscopy is not advocated in the evaluation of uncomplicated urinary incontinence
      • Cystoscopy should be considered in patients with urinary urgency, hematuria, or other irritative symptoms, particularly if they have undergone a previous anti-incontinence procedure, pelvic radiation, or pelvic prolapse repair.
  • Urodynamics
    • Should only be performed when it is going to change the management of the patient
      • Similar to cystourethroscopy, the routine use of UDS is the subject of much discussion; however, one should or may consider UDS in patients who are considering invasive, potentially morbid or irreversible surgery; have failed previous pelvic floor reconstruction; or have mixed incontinence, urinary urgency, or obstructive symptoms; and in patients who have elevated PVRs or neurologic disease.
    • Multichannel UDS offers an extensive evaluation of LUT function.
      • The degree of accuracy provided by multichannel UDS is important in a variety of circumstances, including:
        • Conservative treatment methods fail
        • Diagnosis is unclear
        • Previous diagnostic procedures are inconclusive
        • Clinical pictures complicated by radiation therapy, neurologic disease, or prior failed pelvic floor reconstruction or antiincontinence surgery
        • Symptoms that cannot be confirmed by the clinician.
    • One important scenario that can occur during urodynamics is cough-induced detrusor overactivity incontinence, which happens when the patient coughs and this action initiates an involuntary detrusor contraction, and the patient leaks because of the detrusor overactivity contraction rather than because of the raised intra-adominal pressure generated by the cough. Clinically, it sounds as if the patient is leaking because of SUI, whereas the urodynamics show that he has cough-induced detrusor overactivity.
    • Occult SUI is SUI unmasked by reduction of prolapse; 11-50% of clinically continent patients will develop de novo SUI after repair of high-grade prolapse.
    • Colpopexy and Urinary Reduction Efforts (CARE) trial
      • Population: women with SUI undergoing sacrocolpopexy for prolapse
      • Randomized to concomitant Burch colposuspension vs. no concomitant procedure
      • Results
        • Premature termination of trial after the first interim analysis at 3 months which showed significant reduction in SUI in patient undergoing Burch vs. control (24% vs. 44%)
  • Pad tests
    • Can be helpful in quantifying leakage
    • Tedious and cumbersome; generally used for academic purposes.
      • Most guidelines have not recommended the use of pad testing.
      • Many investigators advocate for pad tests in clinical trials, because pad tests can provide objective, precise information for assessment of actual volume of urine lost over an established period.
      • The International Continence Society recommends both a 3-day bladder diary and pad weight test as proper measures for symptom quantification in incontinence research.
    • Urine loss >1.3g is considered a positive 24-hour pad test, whereas others consider up to 8g of urine loss in 24 hours to be normal
      • Vaginal secretions should be taken into consideration, although the volume attributable to normal vaginal secretions may be as low as 0.3g in 24 hours.
  • Dye testing in females
    • Can be helpful to verify that the leakage represents urine versus another fluid such as vaginal discharge or peritoneal fluid and to substantiate the diagnosis of urinary tract fistulae.
    • Oral phenazopyridine (100-200mg three times per day), also known as pyridium, colors the urine orange, and this simple test can confirm that the leakage fluid is indeed urine.
    • Diagnosis of a vesicovaginal or urethrovaginal fistula can be supported by blue or orange staining of an intravaginal tampon after intravesical instillation of methylene blue or pyridium dissolved in sterile water or saline.
    • In the case of a suspected ureterovaginal fistula, intravesical methylene blue with concurrent oral phenazopyridine (pyridium) can elucidate the fistula location based on the staining pattern on the vaginal tampon
      • Orange staining suggests a ureteral communication
      • Blue staining suggests a bladder communication
      • Simultaneous vesicovaginal and ureterovaginal fistulae can occur.

References

• Wein AJ, Kavoussi LR, Partin AW, Peters CA (eds): CAMPBELL-WALSH UROLOGY, ed 11. Philadelphia, Elsevier, 2015, chap 72
• Wein AJ, Kavoussi LR, Partin AW, Peters CA (eds): CAMPBELL-WALSH UROLOGY, ed 11. Philadelphia, Elsevier, 2015, chap 74