Adult Constipation

Introduction

Adult constipation is a common gastrointestinal complaint encountered in Canadian primary care settings. This comprehensive guide is designed to help medical students preparing for the Medical Council of Canada Qualifying Examination Part I (MCCQE1) understand the key aspects of adult constipation, with a focus on Canadian healthcare practices and guidelines.

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Understanding adult constipation is crucial for success in the MCCQE1 exam and for future practice in the Canadian healthcare system.

Definition and Epidemiology

Constipation is generally defined as:

Fewer than three bowel movements per week
Difficult or painful defecation
Hard or lumpy stools

In Canada, the prevalence of constipation is estimated to be:

Population	Prevalence
General adult population	15-20%
Elderly (>65 years)	Up to 30%
Long-term care residents	Up to 50%

Etiology

Understanding the causes of constipation is essential for MCCQE1 preparation. The etiology can be categorized into primary and secondary causes:

Primary Causes

Slow transit constipation
Normal transit constipation
Defecatory disorders

Secondary Causes

Opioids
Anticholinergics
Calcium channel blockers
Iron supplements
Antidepressants

Clinical Presentation

Patients with constipation may present with various symptoms. For MCCQE1 success, remember the following key presentations:

Infrequent bowel movements
Straining during defecation
Hard or lumpy stools
Sensation of incomplete evacuation
Abdominal discomfort or bloating

Diagnostic Approach

The diagnostic approach to constipation in the Canadian healthcare system typically follows these steps:

Step 1: Detailed History

Obtain a comprehensive history, including:

Bowel habits
Dietary and fluid intake
Medication use
Medical conditions
Family history

Step 2: Physical Examination

Perform a thorough physical exam, including:

Abdominal examination
Digital rectal examination
Neurological assessment

Step 3: Laboratory Tests

Consider basic laboratory tests:

Complete blood count
Thyroid function tests
Serum calcium
Serum glucose

Step 4: Additional Investigations

If indicated, consider:

Colonoscopy (for patients >50 years or with alarm features)
Anorectal manometry
Defecography

Management

Management of constipation in Canada follows a stepwise approach:

Lifestyle modifications
- Increase dietary fiber intake (aim for 25-30g/day)
- Ensure adequate hydration
- Regular physical activity
- Establish a regular toilet routine
Bulk-forming agents
- Psyllium (Metamucil)
- Methylcellulose (Citrucel)
Osmotic laxatives
- Polyethylene glycol (PEG 3350)
- Lactulose
Stimulant laxatives
- Bisacodyl
- Senna
Newer agents
- Linaclotide
- Prucalopride

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In Canada, the choice of laxative should be tailored to the patient's preferences, cost considerations, and potential side effects. Always consult the most recent Canadian guidelines for up-to-date recommendations.

Canadian Guidelines

The Canadian Association of Gastroenterology (CAG) has published guidelines for the management of chronic constipation. Key recommendations include:

A thorough history and physical examination should be performed before initiating treatment.
Routine colonoscopy is not recommended in patients with chronic constipation without alarm features.
First-line treatments include lifestyle modifications and over-the-counter laxatives.
Newer agents like linaclotide and prucalopride should be considered for patients who fail first-line treatments.

Key Points to Remember for MCCQE1

🔑 Constipation is defined as fewer than three bowel movements per week or difficult/painful defecation.
🔑 The Rome IV criteria are used for diagnosis of functional constipation.
🔑 Always consider secondary causes, including medications and medical conditions.
🔑 Management follows a stepwise approach, starting with lifestyle modifications.
🔑 Colonoscopy is indicated for patients >50 years or those with alarm features.
🔑 Newer agents like linaclotide and prucalopride are available in Canada for refractory cases.

MCCQE1 Practice Question

Sample Question

A 68-year-old woman presents with a 6-month history of constipation. She reports having fewer than two bowel movements per week and often needs to strain during defecation. She has tried increasing her fiber intake and fluid consumption without improvement. Her medical history is significant for hypertension and osteoarthritis. Which of the following is the most appropriate next step in management?

Explanation

The correct answer is:

B. Order a colonoscopy

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Explanation: Given the patient's age (>50 years) and new-onset constipation, a colonoscopy is indicated to rule out colorectal cancer or other structural abnormalities. In the Canadian healthcare system, screening for colorectal cancer is recommended for all adults aged 50-74 years, and new-onset constipation in this age group warrants further investigation before initiating treatment.

References

Canadian Association of Gastroenterology. (2017). Clinical Practice Guidelines for the Management of Chronic Constipation. Journal of the Canadian Association of Gastroenterology, 1(1), 41-57.
Bharucha, A. E., Dorn, S. D., Lembo, A., & Pressman, A. (2013). American Gastroenterological Association medical position statement on constipation. Gastroenterology, 144(1), 211-217.
Canadian Task Force on Preventive Health Care. (2016). Recommendations on screening for colorectal cancer in primary care. CMAJ, 188(5), 340-348.
Paquette, I. M., Varma, M., Ternent, C., Melton-Meaux, G., Rafferty, J. F., Feingold, D., & Steele, S. R. (2016). The American Society of Colon and Rectal Surgeons' Clinical Practice Guideline for the Evaluation and Management of Constipation. Diseases of the Colon & Rectum, 59(6), 479-492.
Canadian Society of Intestinal Research. (2021). Constipation. Retrieved from https://badgut.org/information-centre/a-z-digestive-topics/constipation/ (opens in a new tab)

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