What is the initial workup for a patient presenting with fecal incontinence?

Initial Workup for Fecal Incontinence

The initial workup for fecal incontinence should include a thorough clinical assessment, digital rectal examination, and basic laboratory testing before proceeding to specialized tests such as anorectal manometry and imaging studies. 1

Clinical Assessment

History

• Detailed characterization of bowel habits and circumstances surrounding fecal incontinence:
  • Frequency and severity of episodes
  • Relationship to meals and activities
  • Stool consistency (using Bristol stool chart - type 5 and above indicates diarrhea) 1
  • Ability to sense rectal filling
  • Urgency before episodes
  • Prior treatments and their effectiveness 1

Risk Factor Assessment

• Identify key risk factors:
  • Diarrhea (strongest risk factor with OR=53) 1
  • Obstetrical trauma/history
  • Prior anorectal surgeries
  • Neurological disorders (stroke, dementia, spinal cord injury)
  • Diabetes or other conditions causing peripheral neuropathy
  • Inflammatory bowel disease
  • Advanced age
  • Cholecystectomy
  • Current smoking
  • History of rectocele
  • Stress urinary incontinence
  • Higher BMI 1

Physical Examination

• Digital rectal examination is essential and should include:
  • Assessment of resting sphincter tone
  • Evaluation of sphincter augmentation during squeeze
  • Assessment of the puborectalis muscle
  • Evaluation of expulsionary forces
  • Testing for localized tenderness along puborectalis (feature of levator ani syndrome) 1
  • Checking for rectocele or other pelvic floor abnormalities 1
  • Assessment for fecal impaction (which can cause overflow incontinence) 1

Laboratory Testing

• Complete blood count is strongly recommended as the primary screening test 2
• Consider metabolic tests (thyroid-stimulating hormone, serum glucose, creatinine, calcium) if clinically indicated, though their utility is likely low 1

Specialized Testing

After initial assessment, if the cause remains unclear or if surgical intervention is being considered, proceed with:

First-line Specialized Tests

1. Anorectal manometry - to identify:

   • Anal weakness
   • Reduced or increased rectal sensation
   • Impaired rectal balloon expulsion 1

2. Anal imaging (if surgery or devices are being considered):

   • Endoanal ultrasound (preferred for internal sphincter tears)
   • MRI (better for external sphincter defects)
   • These can identify sphincter defects, atrophy, and patulous anal canal 1

Second-line Specialized Tests (if indicated)

• Defecography - to identify structural abnormalities like rectocele, enterocele, or rectal intussusception 2
• Pudendal nerve conduction studies - particularly important as a predictor of functional outcome 3
• Electromyography - to assess sphincter innervation 4

Common Pitfalls to Avoid

1. Misdiagnosis: Fecal incontinence is commonly misinterpreted as diarrhea by patients, and this discrepancy must be clarified during initial assessment 1

2. Incomplete evaluation: Many patients labeled as "refractory" to conservative therapy have not received an optimal trial of such therapy 1

3. Overlooking fecal impaction: Patients with fecal seepage often have evacuation disorders with overflow of retained stool in the rectum 1

4. Failure to identify defecatory disorders: These can be effectively managed with pelvic floor biofeedback therapy 1

5. Inadequate digital rectal examination: A cursory examination without assessment of pelvic floor motion during simulated evacuation is insufficient 1

By following this systematic approach to the workup of fecal incontinence, clinicians can identify the underlying causes and develop appropriate treatment strategies to improve patients' quality of life and reduce morbidity associated with this condition.