Oligoarthralgia: Approach to Pain in One to Four Joints

Introduction

Oligoarthralgia refers to joint pain affecting two to four joints. However, clinically, the approach often overlaps with monoarthritis (one joint) and the early stages of polyarthritis (five or more joints). For the MCCQE1, distinguishing between inflammatory and non-inflammatory causes, and ruling out septic arthritis in acute presentations, are critical competencies.

This guide focuses on the assessment and management of patients presenting with pain in 1-4 joints, tailored for the Medical Council of Canada Qualifying Examination Part I (MCCQE1).

Clinical Approach to Joint Pain

The primary objective in the MCCQE1 is to categorize the pain to narrow the differential diagnosis. The most critical distinction is Inflammatory vs. Non-Inflammatory.

Diagnostic Framework

Differential Diagnosis

The differential for oligoarticular pain is broad. Use the following categorization for your MCCQE1 study strategy.

Investigations

Synovial Fluid Analysis

For acute mono/oligoarthritis with effusion, arthrocentesis is the gold standard investigation.

Imaging

• X-ray: Initial modality. Look for erosions (inflammatory), joint space narrowing/osteophytes (OA), or chondrocalcinosis (CPPD).
• Ultrasound: Detects effusion and synovitis.
• MRI: Best for soft tissue, early erosions, and sacroiliitis (Spondyloarthropathies).

Laboratory Workup

• CBC, ESR, CRP: Markers of inflammation.
• Rheumatoid Factor (RF) / Anti-CCP: If RA suspected (usually poly, but can start oligo).
• HLA-B27: If Spondyloarthropathy suspected (low specificity for screening, use for confirmation in appropriate clinical context).
• Serology: Lyme titers (ELISA followed by Western Blot) if history of tick exposure in endemic areas.

Canadian Guidelines & Choosing Wisely

Choosing Wisely Canada Recommendations

For MCCQE1, knowing what not to do is as important as knowing what to do.

1. Don’t order ANA testing as a screening test in patients without specific signs or symptoms of SLE or other connective tissue diseases.
2. Don’t order HLA-B27 unless there is a high pre-test probability of spondyloarthropathy (e.g., inflammatory back pain).
3. Don’t prescribe antibiotics for septic arthritis before obtaining synovial fluid for culture (unless the patient is unstable/septic, then draw blood cultures and treat).

Lyme Disease in Canada

• Endemic Areas: Parts of Ontario, Quebec, Nova Scotia, New Brunswick, Manitoba, and British Columbia.
• Guideline: Two-tiered testing (ELISA first, then Western Blot if positive/equivocal). Clinical diagnosis is sufficient for Erythema Migrans; serology is for disseminated/late disease (arthritis).

Management Principles

1. Septic Arthritis

• Admission: IV Antibiotics + Joint Drainage (Needle aspiration or Arthroscopic washout).
• Empiric Rx: Cefazolin (or Vancomycin if MRSA risk) + Ceftriaxone (if Gonorrhea suspected).

2. Crystal Arthropathies (Acute)

• NSAIDs: Indomethacin or Naproxen (avoid in renal failure/GI bleed risk).
• Colchicine: Effective if started early (within 24 hours).
• Corticosteroids: Intra-articular (if septic excluded) or systemic (Prednisone) if NSAIDs/Colchicine contraindicated.

3. Spondyloarthropathies

• First line: NSAIDs and Physiotherapy.
• Second line: DMARDs (Sulfasalazine, Methotrexate) for peripheral disease.
• Biologics: TNF-inhibitors (e.g., Infliximab, Adalimumab) for axial disease resistant to NSAIDs.

4. Osteoarthritis

• Non-pharmacologic: Weight loss, exercise, physiotherapy (CanMEDS Health Advocate).
• Pharmacologic: Acetaminophen (limited efficacy), Topical NSAIDs, Oral NSAIDs (with gastroprotection).

Key Points to Remember for MCCQE1

• Septic Arthritis Rule: A hot, swollen joint is septic until proven otherwise. Tap it!
• Gonococcal Arthritis: Consider in young, sexually active patients. Look for the triad of tenosynovitis, dermatitis, and polyarthralgia.
• Reactive Arthritis: Remember the timeline (1-4 weeks post-infection) and the trigger (Chlamydia or GI infection).
• Gout vs. Cellulitis: Gout can cause significant erythema and desquamation, mimicking cellulitis.
• Back Pain: Inflammatory back pain (better with exercise, worse with rest, night pain) points to Ankylosing Spondylitis.

Sample Question

Question

A 26-year-old male presents to the emergency department with a 3-day history of a painful, swollen right knee and left ankle. He reports difficulty walking due to the pain. Review of systems reveals a history of dysuria and urethral discharge 3 weeks ago, which resolved without treatment. He denies any recent trauma or fever. Vital signs are: Temp 37.1°C, BP 124/78 mmHg, HR 82 bpm. Physical examination demonstrates a large effusion and warmth in the right knee and tenderness over the left Achilles tendon insertion.

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

• A. Initiate oral ciprofloxacin
• B. Perform arthrocentesis of the right knee
• C. Order MRI of the lumbar spine
• D. Prescribe oral prednisone
• E. Reassure and discharge with naproxen

Explanation

The correct answer is:

• B. Perform arthrocentesis of the right knee

Detailed Explanation:

This patient presents with an acute asymmetric oligoarthritis (knee and ankle) and enthesitis (Achilles tenderness) following a likely sexually transmitted infection (urethritis). The clinical picture is highly suggestive of Reactive Arthritis (formerly Reiter’s syndrome).

However, the MCCQE1 emphasizes safety and ruling out life-threatening conditions. Even with a classic history for Reactive Arthritis, Septic Arthritis must be ruled out in any patient presenting with an acute, hot, swollen joint (especially the knee) before initiating immunosuppressive therapy or assuming a sterile inflammatory process. Therefore, synovial fluid analysis (arthrocentesis) is the mandatory next step to evaluate for cell count, gram stain, and crystals.

• Option A (Ciprofloxacin): While the trigger may have been Chlamydia, treating the infection now does not reliably treat the reactive arthritis, and antibiotics should not be started without confirming the diagnosis or ruling out a septic joint.
• Option C (MRI Spine): While Reactive Arthritis is a spondyloarthropathy and can involve the spine, this is not the immediate priority for an acute peripheral joint effusion.
• Option D (Prednisone): Steroids are contraindicated until septic arthritis is ruled out via arthrocentesis.
• Option E (Naproxen): NSAIDs are the treatment of choice for Reactive Arthritis, but you must first exclude septic arthritis via joint aspiration.

References

1. Medical Council of Canada. MCCQE Part I Clinical Decision-Making and Multiple-Choice Question Guidelines.
2. Choosing Wisely Canada. Rheumatology: Five Things Physicians and Patients Should Question. Link 
3. Public Health Agency of Canada. Lyme disease: For health professionals. Link 
4. Kasper, D. L., et al. Harrison’s Principles of Internal Medicine. 21st Edition. McGraw-Hill Education.
5. Dynamed. Approach to the adult with monoarticular pain. Accessed via CMA Joule.