Polyarthralgia: Pain In More Than Four Joints

Introduction

Polyarthralgia, a common presentation in rheumatology, refers to pain in multiple joints (more than four) without significant swelling or inflammation. This comprehensive guide is designed to help Canadian medical students prepare for the MCCQE1 exam, focusing on the essential aspects of polyarthralgia within the Canadian healthcare context.

Epidemiology in Canada

Polyarthralgia affects a significant portion of the Canadian population, with prevalence varying based on underlying causes:

• Osteoarthritis: Affects approximately 1 in 6 Canadians aged 15 years and older
• Rheumatoid Arthritis: Affects about 1% of Canadians
• Systemic Lupus Erythematosus (SLE): Prevalence of 32.8 per 100,000 in Canada

Etiology and Risk Factors

Understanding the causes of polyarthralgia is crucial for MCCQE1 success. Common etiologies include:

1. Inflammatory Disorders

   • Rheumatoid Arthritis (RA)
   • Systemic Lupus Erythematosus (SLE)
   • Psoriatic Arthritis

2. Non-inflammatory Disorders

   • Osteoarthritis (OA)
   • Fibromyalgia

3. Infectious Causes

   • Lyme Disease (more common in certain Canadian regions)
   • Viral arthritis (e.g., Parvovirus B19, Hepatitis B and C)

4. Metabolic Disorders

   • Gout
   • Pseudogout (Calcium Pyrophosphate Deposition Disease)

5. Other Systemic Diseases

   • Sarcoidosis
   • Thyroid disorders

Clinical Presentation

For MCCQE1 preparation, focus on recognizing key features of polyarthralgia:

1. Pain Characteristics

   • Distribution (symmetrical vs asymmetrical)
   • Duration (acute vs chronic)
   • Timing (morning stiffness duration)

2. Associated Symptoms

   • Fatigue
   • Fever
   • Skin rashes
   • Weight loss

3. Joint Involvement Pattern

   • Small joints (e.g., hands, feet)
   • Large joints (e.g., knees, hips)
   • Axial skeleton involvement

Diagnostic Approach

A systematic approach to diagnosis is essential for MCCQE1 success:

Differential Diagnosis

For MCCQE1 preparation, focus on distinguishing between common causes of polyarthralgia:

Management

Treatment approaches in the Canadian healthcare context:

1. Non-pharmacological Interventions

   • Patient education
   • Physical therapy
   • Occupational therapy
   • Weight management

2. Pharmacological Management

   • NSAIDs
   • Disease-Modifying Antirheumatic Drugs (DMARDs)
   • Biologics
   • Corticosteroids

3. Surgical Interventions

   • Joint replacement
   • Arthroscopy

Canadian Guidelines

The Canadian Rheumatology Association (CRA) provides guidelines for managing various rheumatological conditions. Key points for MCCQE1:

1. Rheumatoid Arthritis

   • Early referral to a rheumatologist is recommended
   • Treat-to-target approach aiming for remission or low disease activity
   • Regular monitoring of disease activity and treatment response

2. Osteoarthritis

   • Emphasis on non-pharmacological interventions as first-line treatment
   • Cautious use of opioids, considering their potential risks

3. Systemic Lupus Erythematosus

   • Hydroxychloroquine recommended for all patients unless contraindicated
   • Regular screening for comorbidities (e.g., cardiovascular disease)

Key Points to Remember for MCCQE1

1. Distinguish between inflammatory and non-inflammatory causes of polyarthralgia
2. Recognize red flag symptoms requiring urgent evaluation
3. Understand the role of autoantibodies in diagnosis (RF, anti-CCP, ANA)
4. Be familiar with Canadian guidelines for managing common rheumatological conditions
5. Consider regional variations in disease prevalence (e.g., Lyme disease)
6. Understand the impact of Canada's climate on joint symptoms
7. Be aware of the Canadian healthcare system's approach to managing chronic conditions

Sample Question

A 42-year-old woman presents with a 6-month history of pain and stiffness in multiple joints, including her wrists, knees, and small joints of her hands. She reports morning stiffness lasting about 2 hours. Physical examination reveals swelling and tenderness in the metacarpophalangeal joints bilaterally. Which one of the following investigations is most likely to confirm the diagnosis?

• A. Antinuclear Antibody (ANA) test
• B. Uric Acid level
• C. Anti-Cyclic Citrullinated Peptide (anti-CCP) antibodies
• D. Erythrocyte Sedimentation Rate (ESR)
• E. X-ray of hands and wrists

Explanation

The correct answer is:

• C. Anti-Cyclic Citrullinated Peptide (anti-CCP) antibodies

This patient's presentation is highly suggestive of Rheumatoid Arthritis (RA). The key features include:

• Polyarthralgia affecting small joints of hands, wrists, and knees
• Prolonged morning stiffness (>1 hour)
• Symmetrical joint involvement
• Duration of symptoms (>6 weeks)

While all the listed investigations may be useful in the workup of RA, anti-CCP antibodies are highly specific for RA (specificity >95%). A positive anti-CCP test, along with the clinical presentation, would strongly support the diagnosis of RA.

• ANA (A) is more associated with SLE and other connective tissue diseases.
• Uric Acid level (B) is used to diagnose gout, which typically presents with monoarthritis.
• ESR (D) is a non-specific marker of inflammation and doesn't confirm any specific diagnosis.
• X-rays (E) may show changes in longstanding RA but are often normal in early disease.

References

1. Arthritis Society Canada. (2021). Arthritis in Canada. https://arthritis.ca/about-arthritis/arthritis-facts-and-figures (opens in a new tab)
2. Bykerk, V. P., et al. (2012). Canadian Rheumatology Association recommendations for pharmacological management of rheumatoid arthritis with traditional and biologic disease-modifying antirheumatic drugs. The Journal of Rheumatology, 39(8), 1559-1582.
3. Canadian Rheumatology Association. (2021). Clinical Practice Guidelines. https://rheum.ca/resources/publications/ (opens in a new tab)
4. Gladman, D. D., et al. (2021). 2021 American College of Rheumatology/Vasculitis Foundation Guideline for the Management of Giant Cell Arteritis and Takayasu Arteritis. Arthritis Care & Research, 73(8), 1071-1087.
5. Public Health Agency of Canada. (2020). Lyme Disease in Canada. https://www.canada.ca/en/public-health/services/diseases/lyme-disease.html (opens in a new tab)