Chronic Abdominal Pain: An MCCQE1 Study Guide

Introduction

Chronic abdominal pain is a common presentation in Canadian primary care and gastroenterology practices. For the MCCQE1, candidates must demonstrate the ability to differentiate between organic and functional etiologies, apply the CanMEDS roles (particularly Medical Expert and Communicator), and utilize a cost-effective, evidence-based diagnostic approach.

Definition

Chronic Abdominal Pain: Continuous or intermittent abdominal discomfort lasting for at least 3 to 6 months. It may be related to a specific organic pathology or be a disorder of gut-brain interaction (DGBI), formerly known as functional gastrointestinal disorders.

Pathophysiology and Classification

Understanding the mechanism of pain is crucial for management. In the context of MCCQE1 preparation, categorize pain into three main types:

Visceral Pain: Dull, poorly localized, often midline. Caused by distension or spasm of hollow organs.
Somatic (Parietal) Pain: Sharp, well-localized. Caused by irritation of the parietal peritoneum (e.g., root of mesentery).
Referred Pain: Perceived at a site distant from the affected organ (e.g., shoulder pain from diaphragmatic irritation).

Functional vs. Organic Pain

The most critical clinical decision is distinguishing functional disorders (like IBS) from organic disease (like IBD or malignancy).

Feature	Functional (e.g., IBS, Functional Dyspepsia)	Organic (e.g., IBD, Cancer, Peptic Ulcer)
Course	Long history, often fluctuating	Progressive or stable
Weight Loss	Rare (unless avoidance of food)	Common (Red Flag)
Nocturnal Symptoms	Rare (does not wake patient)	Common (wakes patient from sleep)
Onset	Often <50 years old	Often >50 years old (new onset)
Relationship to Stress	Highly correlated	Variable
Laboratory Findings	Normal	Abnormal (Anemia, CRP, Calprotectin)

Clinical Evaluation

History Taking (MCCQE1 Focus)

When taking a history for the QE1, focus on the OPQRST mnemonic and specifically screen for Alarm Features (Red Flags).

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CRITICAL: Red Flags (Alarm Features) The presence of any of the following mandates organic investigation (e.g., endoscopy, imaging):

Unintentional weight loss
Rectal bleeding / Melena
Nocturnal symptoms waking the patient
Family history of Colorectal Cancer (CRC), IBD, or Celiac Disease
Onset after age 50 (Canadian screening age for CRC)
Progressive dysphagia or odynophagia
Unexplained iron deficiency anemia
Palpable mass or lymphadenopathy

Physical Examination

General: Signs of anemia, jaundice, wasting.
Abdominal: Distension, scars (adhesions), masses, organomegaly, focal tenderness.
Digital Rectal Exam (DRE): Essential if there are changes in bowel habits or rectal bleeding.

Diagnostic Approach

A stepwise approach prevents over-investigation, aligning with Choosing Wisely Canada recommendations.

Step 1: Baseline Investigations

For most patients with chronic pain, limited screening is appropriate to rule out common organic causes.

CBC: Rule out anemia/infection.
CRP: Rule out inflammation (IBD).
Tissue Transglutaminase IgA (tTG-IgA): Screen for Celiac Disease (High prevalence in Canada).
Urinalysis: Rule out chronic UTI/stones.

Step 2: Targeted Testing

Based on the predominant symptom profile:

Diarrhea-predominant: Fecal calprotectin (to differentiate IBS from IBD), Stool culture/O&P (if risk factors exist).
Upper GI symptoms: H. pylori testing (Urea breath test or stool antigen).
Right Upper Quadrant pain: Abdominal Ultrasound.

Step 3: Advanced Investigations

Reserved for patients with Red Flags or those who fail empiric therapy.

Upper Endoscopy (Gastroscopy): Dysphagia, weight loss, age >55 with new dyspepsia.
Colonoscopy: Rectal bleeding, positive FIT (though FIT is for screening asymptomatic only), suspicion of IBD.
CT Abdomen/Pelvis: Suspicion of chronic pancreatitis, structural lesions.

Common Etiologies

Irritable Bowel Syndrome (IBS)

Irritable Bowel Syndrome (IBS)

The most common cause of chronic abdominal pain in young Canadians.

Rome IV Criteria: Recurrent abdominal pain (at least 1 day/week in the last 3 months) associated with two or more of the following:
1. Related to defecation.
2. Associated with a change in frequency of stool.
3. Associated with a change in form (appearance) of stool.
Subtypes: IBS-C (Constipation), IBS-D (Diarrhea), IBS-M (Mixed).
MCCQE1 Tip: Diagnosis is clinical if no red flags are present. Do not order a CT scan for typical IBS.

Management Strategies

Management should follow a Bio-psychosocial approach.

1. Non-Pharmacologic Management

Dietary:
- FODMAP Diet: Evidence-based for IBS. Recommended to be done under dietitian supervision.
- Fiber: Soluble fiber (e.g., Psyllium) is better tolerated than insoluble fiber (bran) for IBS.
Psychological Therapies: CBT and Hypnotherapy are proven effective for disorders of gut-brain interaction.

2. Pharmacologic Management

Condition	First-Line Agents	Second-Line / Adjuncts
IBS-D	Loperamide (prn)	Tricyclic Antidepressants (TCAs), Rifaximin (restricted coverage in Canada), Eluxadoline
IBS-C	Osmotic laxatives (PEG 3350), Psyllium	Linaclotide, Prucalopride
Functional Dyspepsia	PPI (trial for 4-8 weeks)	TCAs, Prokinetics (Domperidone)
Chronic Pain (General)	Antispasmodics (Pinaverium, Dicyclomine)	Neuromodulators (Low dose Amitriptyline or Nortriptyline)

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Opioid Stewardship: Opioids are contraindicated for chronic functional abdominal pain (IBS/Functional Dyspepsia) due to the risk of Narcotic Bowel Syndrome (Opioid-Induced Hyperalgesia).

Canadian Guidelines

Choosing Wisely Canada

Don’t perform abdominal CT scans for the evaluation of functional abdominal pain in children or young adults unless there are alarm symptoms or signs.
Don’t maintain long-term PPI therapy for gastrointestinal symptoms without an attempt to stop/reduce dose at least once per year.

Canadian Association of Gastroenterology (CAG)

For uninvestigated dyspepsia: If age >60 (or >55 in some contexts) or alarm features → Gastroscopy.
If age <60 and no alarm features → Test and Treat for H. pylori.

Key Points to Remember for MCCQE1

Diagnosis of Exclusion: IBS and Functional Dyspepsia are positive diagnoses based on criteria (Rome IV), not just “diagnoses of exclusion” after exhaustive testing.
Celiac Disease: Always screen with tTG-IgA in patients with IBS-D or mixed symptoms, as Celiac is common in Canada (~1%).
Pelvic Exam: In females with lower abdominal pain, do not forget to consider gynecological causes (Endometriosis, PID) and perform a pelvic exam.
Somatic vs. Visceral: Carnett’s sign (increased pain with abdominal wall tensing) suggests abdominal wall pain (somatic), not visceral pathology.

Sample Question

Clinical Scenario

A 26-year-old woman presents to her family physician with a 6-month history of intermittent lower abdominal cramping. She reports that the pain is often relieved by defecation and is associated with loose, watery stools occurring 3–4 times per day. She notes abdominal bloating that worsens throughout the day. She denies rectal bleeding, weight loss, or nocturnal symptoms. Her past medical history is unremarkable. There is no family history of inflammatory bowel disease or colorectal cancer. Physical examination reveals mild tenderness in the left lower quadrant without rebound or guarding. Digital rectal examination is normal.

Question

Which one of the following is the most appropriate next step in the management of this patient?

A. Refer for colonoscopy
B. Order a CT scan of the abdomen and pelvis
C. Prescribe a trial of opioids for pain control
D. Order a complete blood count (CBC) and tissue transglutaminase IgA (tTG-IgA)
E. Initiate a gluten-free diet immediately

Explanation

The correct answer is:

D. Order a complete blood count (CBC) and tissue transglutaminase IgA (tTG-IgA)

Detailed Explanation: This patient presents with classic symptoms of Irritable Bowel Syndrome - Diarrhea predominant (IBS-D) based on the Rome IV criteria (recurrent abdominal pain related to defecation, associated with a change in stool frequency/form).

Why D is correct: While IBS is a clinical diagnosis, Canadian guidelines recommend a limited screen to rule out common organic mimickers, specifically Celiac Disease and anemia/inflammation. Celiac disease has a prevalence of approximately 1% in Canada and symptoms overlap significantly with IBS-D. A CBC checks for anemia (an alarm feature).
Why A is incorrect: Colonoscopy is not indicated in a young patient (<50 years) with typical IBS symptoms and no alarm features (no bleeding, weight loss, nocturnal symptoms, or family history of CRC/IBD).
Why B is incorrect: CT imaging involves significant radiation and has a low yield for diagnosing IBS. Choosing Wisely Canada specifically advises against this in young patients with functional symptoms.
Why C is incorrect: Opioids are contraindicated in IBS as they can cause Narcotic Bowel Syndrome and worsen constipation/motility issues.
Why E is incorrect: A gluten-free diet should never be started before testing for Celiac disease, as it will normalize serology and histology, making subsequent diagnosis impossible without a gluten challenge.

References

Medical Council of Canada. MCCQE Part I Clinical Decision-Making and Multiple-Choice Questions Objectives.
Canadian Association of Gastroenterology (CAG). Clinical Practice Guidelines for the Management of Irritable Bowel Syndrome (IBS). https://www.cag-acg.org
Choosing Wisely Canada. Gastroenterology Recommendations. https://choosingwiselycanada.org/gastroenterology/
Lacy BE, et al. Bowel Disorders. Gastroenterology. 2016 (Rome IV Criteria).
Moayyedi P, et al. Canadian Association of Gastroenterology Clinical Practice Guideline for the Management of Uninvestigated Dyspepsia.