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A. Epidemiology

  1. Overall prevalance ~2% in USA, up to 50% of nursing home patients
  2. Affects ~10% persons >64 years
  3. About 50% of persons with urinary incontinence also have fecal incontinence
  4. Highly associated with anxiety, embarrassment, social isolation

B. Etiology (Table 1, Ref [1])

  1. Fecal Impaction - usually with reduced stool sensation
  2. Loss of Normal Continence Mechanisms
    1. Local nerve damage: such as pudendal nerve
    2. Impaired neurological control: spinal reflex arc, autonomic control, central inhibition
    3. Spinal cord lesion
    4. Peripheral neuropathy due to diabetes, multiple sclerosis
    5. Anorectal Trauma
  3. Anorectal Trauma / Sphincter Disruption
    1. Birth trauma - weakness of external anal sphincter only
    2. Anal dilitation (sphincterotomy) - weakness of internal anal sphincter
    3. Anal surgery
    4. Ostomy
  4. Problems Overwhelming Normal Continence Mechanisms (Overflow)
    1. Diarrhea / Colitis
    2. Poor access to toilets
    3. Laxatives
    4. Radiation
  5. Reduced Storage Capacity
    1. Inflammatory bowel disease (IBD)
    2. Radiation therapy - particularly for prostate cancer
    3. Proctectomy or other rectal surgery
  6. Weakness of Puborectalis Muscle
    1. Spinal cord lesion
    2. Peripheral neuropathy
    3. "High" tear after vaginal delivery
  7. Psychological and Behavioral Problems
    1. Severe depression
    2. Dementia
    3. Delirium
  8. Physical Functional Impairment
    1. Hemiparesis
    2. Arthritis
    3. Gait Instability
  9. Neoplasm - rare
  10. Fecal urgency with incontinence (rectal hypersensitivity) may be due to elevated levels of heat and capsaicin receptor vanilloid receptor 1 (TRPV1 or VR1) [4]

C. Evaluation

  1. History
    1. Must be elicited; patients rarely volunteer information
    2. Inquire as to when symptoms initially occurred
    3. Frequency and timing of occurrance of incontinence
    4. How incontinence affects daily activities, social events
    5. Evaluate for etiologies above
  2. Physical Exam
    1. Helps identify etiology and guides additional testing
    2. Neurologic examination including mobility, motor strength, sensory testing
    3. Anal wink: stroke skin lateral to anal canal and observe contraction
    4. Absence of anal wink suggests marked neurologic damage
    5. Inspect perineum: dermatitis, hemorrhoids, fistula, surgical scars, prolapse, soiling
    6. Note baseline sphincter tone, squeeze pressure, any asymmetry
    7. Amount and character of stool
  3. Diagnostic Tests
    1. Priority in diagnostic tests is to exclude fecal impaction
    2. Plain abdominal radiography is first test
    3. Colonoscopy or sigmoidoscopy
    4. Ultrasonography
    5. Anorectal manometry - usually recommended after trial of conservative treatments
    6. MRI of pelvis
  4. Diarrhea should be thoroughly investigated and treated

D. Treatment

  1. Fecal Impaction
    1. Disimpaction and colon cleansing
    2. Large volume warm-water enemas or oral polyethylene glycol (PEG) with electrolytes
    3. Ongoing program of bowel management including high fiber diet
  2. Conservative
    1. Must exclude fecal impaction
    2. Antidiarrheal (if not contraindicated)
    3. Regular post-meal bowel regimen
  3. Bedbound patients treated with scheduled osmotic or stimulant laxative if constipated
  4. Weak Anorectal Tone
    1. Biofeedback may improve week anorectal tone; randomized trials have not shown benefit
    2. Sphincteroplasty if conservative management or biofeedback fails
    3. Artificial anorectal sphincter - makeshift with cotton balls or true sphincter
    4. An artificial anal sphincter with reasonably good success has been developed [5]
  5. Stimulation of Sacral Nerve
    1. Clinical improvement successful in most patients when nerve successfully located
    2. Phase I involves locating sacral spinal nerves on percutaneous probing
    3. Phase II involves temporary placement of electrode to maximally stimulate sphincter
    4. Phase III involves permanent implantation of neurostimulator for long term use

References

  1. Wald A. 2007. NEJM. 356(16):1649
  2. Landefeld CS, Bowers BJ, Feld AD, et al. 2008. Ann Intern Med. 148(6):449 abstract
  3. Madoff RD, Parker SC, Varma MG, Lowry AC. 2004. Lancet. 364(9434):623
  4. Chan CLH, Facer P, Davis JB, et al. 2003. Lancet. 361(9355):385 abstract
  5. Vaizey CJ, Kamm MA, Gold DM, et al. 1998. Lancet. 352(9122):105 abstract