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BASICS

  • Involuntary passage of feces through anal canal >1 month in previously continent individual
  • Categories: Major (involuntary stool evacuation), Minor (flatus/occasional seepage)
  • Types: Urge and passive incontinence
  • Endorectal ultrasound (EUS) is reliable, noninvasive to detect sphincter defects
  • Goal: Restore continence and improve quality of life

EPIDEMIOLOGY

  • Prevalence: 7% adults, increasing to 15% in those >90 years
  • More common in women
  • 56-66% of hospitalized older adults and >50% nursing home residents affected
  • 50-70% with urinary incontinence also have fecal incontinence
  • Obstetric injury common cause in pregnancy

ETIOLOGY AND PATHOPHYSIOLOGY

  • Complex coordination of pelvic muscles, nerves, reflex arcs required for continence
  • Factors: stool volume/consistency, colon transit, anorectal sensation, rectal compliance, reflexes, sphincter tone, puborectalis function, cognition
  • Congenital: spina bifida, myelomeningocele
  • Trauma: obstetric, surgical
  • Medical: diabetes (pudendal neuropathy), stroke, spinal cord injury, neurodegeneration, IBD, rectal tumors
  • No clear genetic links found

RISK FACTORS

  • Older age, female sex, obesity, low physical activity
  • Neurologic disorders: MS, stroke, spinal injury, diabetic neuropathy, dementia, depression
  • Pelvic trauma: surgery, vaginal delivery (esp. prolonged labor, assisted delivery, episiotomy)
  • GI disorders: diarrhea, IBS, IBD, constipation, fecal impaction
  • Congenital anomalies: imperforate anus, rectal prolapse

PREVENTION

  • Lifestyle: weight control, exercise, diet, smoking cessation
  • Scheduled bowel emptying after meals (gastrocolic reflex)
  • Pelvic floor exercises during/after pregnancy or surgery
  • Increase dietary fiber (>30 g/day)

COMMON ASSOCIATED CONDITIONS

  • Diabetes, dementia, stroke, depression, immobility
  • COPD, IBS, IBD
  • Perineal trauma, pelvic surgery, radiation
  • Urinary incontinence, pelvic organ prolapse

DIAGNOSIS

History

  • Often underreported; direct questioning needed
  • Assess stool consistency, frequency, severity, constipation or diarrhea
  • Review diet, medications, obstetric and surgical history, lifestyle, mobility
  • Screen for depression, social withdrawal

Physical Exam

  • Inspect perineum: dermatitis, scars, hemorrhoids, prolapse, soiling
  • Anal wink reflex (absent suggests neuropathy)
  • Bear down test for prolapse (standing preferred)
  • Digital rectal exam: tone, bleeding, hemorrhoids, stool consistency
  • Neurologic exam including perianal sensation and mental status

Differential Diagnosis

  • Anorectal: hemorrhoids, prolapse, trauma, infection, ischemia, neoplasm
  • Neurologic: stroke, dementia, spinal cord disease, pudendal neuropathy
  • Others: infectious diarrhea, impaction/overflow, IBS, myopathy, behavioral

DIAGNOSTIC TESTS

  • Usually clinical diagnosis
  • Imaging: abdominal x-ray (fecal impaction), sigmoidoscopy, colonoscopy if indicated
  • Stool studies: culture, parasites, C. difficile if relevant
  • Labs: TSH, electrolytes, BUN in elderly
  • EUS: best for sphincter defects and predicting response to surgery
  • Defecography (plain or MRI) for prolapse and pelvic floor assessment
  • Anorectal manometry: sphincter pressures, reflexes, sensation
  • Pudendal nerve terminal motor latency (PNTML) and EMG for neuromuscular assessment

TREATMENT

General Measures

  • Scheduled or prompted defecation, especially for overflow incontinence
  • Pelvic floor (Kegel) exercises
  • Stool deodorants and barrier creams for dermatitis
  • Bowel regimens in bedridden patients

Medications

  • Treat underlying causes (e.g., diarrhea, IBD)
  • Stool bulking agents (fiber, psyllium, methylcellulose) for mild incontinence
  • Antidiarrheals (loperamide, codeine) for diarrhea-associated incontinence
  • Limited evidence for sphincter tone enhancers (phenylephrine gel, sodium valproate)

Additional Therapies

  • Biofeedback therapy for patients with voluntary control and motivation
  • Biofeedback + electrical stimulation more effective than either alone

Surgery

  • Reserved for refractory cases with defined sphincter defects
  • Sphincteroplasty
  • Injectable tissue bulking agents for internal sphincter dysfunction
  • Artificial anal sphincter or dynamic graciloplasty for severe, irreparable damage
  • Colostomy/ileostomy for disabling incontinence failing all therapies
  • Anal plugs for selected immobilized/neurologically impaired patients (often poorly tolerated)
  • Sacral nerve stimulation (neuromodulation) improves tone and continence
  • SECCA procedure (radiofrequency ablation) for mild/moderate cases
  • Magnetic anal sphincter devices for moderate/severe incontinence
  • Vaginal bowel control devices (Eclipse system)
  • Posterior tibial nerve stimulation and mesh pelvic floor repair (TOPAS system) emerging options

Complementary & Alternative Medicine

  • Acupuncture shows some QoL improvement but limited data

INPATIENT CARE

  • Manual fecal evacuation for impaction with lubrication
  • Avoid hot water, soap, hydrogen peroxide enemas

ONGOING CARE

  • Periodic rectal exams
  • Monitor bowel movement frequency; consider impaction if <1 every other day

DIET

  • High fiber (20–30 g/day)
  • Adequate hydration (>1.5 L/day)
  • Avoid caffeine and other precipitants

PATIENT EDUCATION

  • Kegel exercises useful but insufficient alone
  • Encourage bowel training and lifestyle modifications

PROGNOSIS

  • High recurrence of impaction if bowel regimen stopped
  • ~50% failure rate for overlapping sphincteroplasty at 5 years

COMPLICATIONS

  • Depression, social isolation
  • Skin ulcerations
  • Artificial bowel sphincter: infection, erosion, mechanical failure

REFERENCES

  1. Tjandra JJ, Dykes SL, Kumar RR, et al. Practice parameters for the treatment of fecal incontinence. Dis Colon Rectum. 2007;50(10):1497-1507.
  2. Omar MI, Alexander CE. Drug treatment for faecal incontinence in adults. Cochrane Database Syst Rev. 2013;(6):CD002116.
  3. Assmann SL, Keszthey D, Kleijnen J, et al. Guideline for the diagnosis and treatment of faecal incontinence—a URG/ESCP/ESNM/ESPCC collaboration. United European Gastroenterol J. 2022;10(3):251-286.
  4. Rosenblatt P. New developments in therapies for fecal incontinence. Curr Opin Obstet Gynecol. 2015;27(5):353-358.

Clinical Pearls

  • Scheduled defecation after meals, bulking agents, and enemas minimize fecal impaction
  • Differentiate true fecal incontinence from overflow or functional pseudoincontinence
  • New onset incontinence warrants evaluation for spinal cord compression