Fecal Incontinence

Introduction

Fecal Incontinence (FI) is the recurrent uncontrolled passage of fecal material for at least 3 months in an individual with a developmental age of at least 4 years. For MCCQE1 preparation, it is crucial to understand FI not just as a physiological failure, but as a condition with profound psychosocial impacts, requiring a sensitive Health Advocate approach within the CanMEDS framework.

In the Canadian context, FI is a major determinant for admission to Long-Term Care (LTC) facilities. It affects approximately 2-10% of the general adult population, with prevalence rising significantly in the elderly.

Etiology and Pathophysiology

Understanding the mechanism is key to selecting the appropriate investigation and management strategy. FI is generally classified into three categories: Passive Incontinence, Urge Incontinence, and Fecal Seepage.

Key Pathophysiological Mechanisms

• Internal Anal Sphincter (IAS): Responsible for 80% of resting tone. Damage leads to passive incontinence.
• External Anal Sphincter (EAS): Responsible for squeeze pressure. Damage leads to urge incontinence.
• Rectal Sensation: Impairment leads to lack of awareness of stool presence.
• Rectal Compliance: Reduced compliance (e.g., radiation proctitis) causes urgency.

Clinical Assessment

History Taking

A detailed history is the cornerstone of the diagnosis. Patients often do not volunteer this information due to embarrassment.

Key Historical Points to Elicit:

• Obstetric History: Forceps delivery, prolonged labour, 3rd/4th-degree tears (OASIS).
• Surgical History: Previous hemorrhoidectomy, fistulotomy, or midline episiotomy.
• Stool Consistency: Differentiate between true incontinence and overflow diarrhea (fecal impaction).
• Medication Review: Laxatives, metformin, SSRIs, or anticholinergics.

Physical Examination

Diagnostic Investigations

Investigations should be guided by the clinical picture.

Management

Management follows a stepped approach, starting with conservative measures.

1. Conservative Management (First-Line)

• Dietary Modification: Avoid caffeine, alcohol, lactose, and spicy foods.
• Fibre Supplementation: Psyllium (Metamucil) acts as a bulking agent to improve stool consistency and rectal sensation.
  • Note: Start low and go slow to avoid bloating.
• Skin Care: Barrier creams (zinc oxide) to prevent dermatitis.
• Scheduled Toileting: Especially for elderly/dementia patients (gastrocolic reflex utilization).

2. Pharmacological Therapy

• Antidiarrheals: Loperamide (Imodium) increases resting anal tone and reduces stool frequency.
  • Dosing: 2-4 mg PRN or scheduled (max 16 mg/day).
• Cholestyramine: Useful for bile acid malabsorption (e.g., post-cholecystectomy).

3. Biofeedback Therapy

Indicated for patients with intact sphincters but impaired sensation or coordination. It is highly effective (evidence-based) for strengthening the pelvic floor.

4. Surgical Management

Reserved for patients who fail conservative and medical therapy.

Canadian Guidelines

Obstetric Anal Sphincter Injuries (OASIS)

The Society of Obstetricians and Gynaecologists of Canada (SOGC) guidelines emphasize:

• Proper repair of 3rd and 4th-degree tears at the time of delivery is crucial.
• Women with transient FI after delivery should be offered physiotherapy.
• Women with permanent FI or abnormal manometry/ultrasound post-repair should be counselled regarding Cesarean section for future pregnancies to preserve remaining function.

Long-Term Care (LTC)

In Canadian LTC settings, management focuses on dignity and skin integrity. “Check and change” protocols are insufficient; prompted voiding and defecation schedules are recommended standards of care.

Key Points to Remember for MCCQE1

• Fecal Impaction: Always rule out overflow incontinence (pseudoincontinence) via DRE in elderly patients presenting with diarrhea/incontinence.
• Loperamide: Mechanism is dual-action: slows transit time AND increases internal anal sphincter tone.
• Investigation Hierarchy: History/Physical $\rightarrow$ Endoscopy (if red flags) $\rightarrow$ Anorectal Manometry (gold standard for functional assessment) $\rightarrow$ Endoanal US (for structural defects).
• CanMEDS: Address the social isolation and depression associated with FI.

Sample Question

Clinical Scenario

A 68-year-old female presents to her family physician complaining of involuntary loss of stool. She reports that she often soils her undergarments without sensing the need to defecate. She has a history of three vaginal deliveries, one of which required forceps. She denies abdominal pain, blood in the stool, or weight loss. Her bowel movements are generally loose (Bristol type 6). Digital rectal examination reveals decreased resting anal tone but normal squeeze tone. There is no fecal impaction.

Which one of the following is the most appropriate initial management step for this patient?

Options

• A. Refer for anorectal manometry
• B. Prescribe oral loperamide and fibre supplementation
• C. Refer for surgical sphincteroplasty
• D. Prescribe oral antibiotics for bacterial overgrowth
• E. Schedule a colonoscopy

Explanation

The correct answer is:

• B. Prescribe oral loperamide and fibre supplementation

Detailed Explanation: This patient presents with passive fecal incontinence, likely due to Internal Anal Sphincter (IAS) dysfunction (suggested by low resting tone) and potentially loose stools.

• Option B is correct: The initial management of fecal incontinence, in the absence of red flags (alarm symptoms), is conservative. This includes dietary modification, fibre supplementation (to bulk the stool), and antidiarrheals like loperamide (which improves stool consistency and increases resting anal sphincter tone). This aligns with Canadian clinical practice guidelines favoring non-invasive measures first.
• Option A is incorrect: While anorectal manometry is the appropriate diagnostic test to confirm the pathophysiology, it is generally reserved for patients who fail conservative management or are being considered for surgery. It is not the initial management step.
• Option C is incorrect: Surgery is reserved for patients who have failed conservative and medical management and have a demonstrable structural defect.
• Option D is incorrect: Antibiotics are not indicated as there is no evidence of infection or bacterial overgrowth in the stem.
• Option E is incorrect: While age-appropriate screening is important, this patient has no red flags (no blood, no weight loss, no pain) suggesting a need for immediate colonoscopy to explain the incontinence. However, she should be up to date with her colorectal cancer screening guidelines.

References

1. Society of Obstetricians and Gynaecologists of Canada (SOGC). (2023). Obstetrical Anal Sphincter Injuries (OASIS): Prevention, Diagnosis, and Repair. SOGC Clinical Practice Guidelines.
2. Canadian Association of Gastroenterology. (2022). Clinical Practice Guidelines for the Management of Irritable Bowel Syndrome (IBS). [Relevant for stool consistency management].
3. Wald, A. (2023). Fecal Incontinence in Adults: Etiology and Evaluation. UpToDate.
4. Medical Council of Canada. (2024). MCCQE Part I Clinical Decision-Making and Objectives: Gastrointestinal System.
5. Rao, S. S. C. (2018). Diagnosis and Management of Fecal Incontinence. American Journal of Gastroenterology. (Standard reference for North American practice).