Internal Medicine · Year 3 · from Internal Medicine
Case 1: Rheumatoid Arthritis
Patient Presentation
A 42-year-old woman presents with 3 months of bilateral hand pain, stiffness, and swelling. She reports that her fingers feel stiff in the morning for approximately 2 hours before loosening up. The pain and stiffness are worse in the morning and after periods of inactivity. She has noticed difficulty opening jars and has been dropping things more frequently.
Vital Signs
- Blood Pressure: 122/74 mmHg
- Heart Rate: 76 bpm
- Temperature: 37.0°C
Physical Examination
- General: Well-appearing
- Hands: Symmetric swelling and tenderness of MCP and PIP joints bilaterally, warmth over affected joints, no DIP involvement
- Wrists: Bilateral synovitis
- Feet: Tenderness at MTP joints bilaterally
- No nodules, no rashes
Laboratory Results
- RF (Rheumatoid Factor): 85 IU/mL (positive, normal <14)
- Anti-CCP antibodies: 124 U/mL (positive, normal <20)
- ESR: 48 mm/hr
- CRP: 2.8 mg/dL
- CBC: Normal
- CMP: Normal
- Hand X-rays: Periarticular osteopenia, soft tissue swelling, no erosions yet
Clinical Image
Figure 1: Clinical photograph of hands demonstrating symmetric swelling of the metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints characteristic of rheumatoid arthritis.
Image Source: Educational illustration for teaching purposes.
Questions
- What classification criteria support the diagnosis of rheumatoid arthritis?
- A) Presence of joint pain only
- B) 2010 ACR/EULAR criteria: joint involvement, serology (RF/anti-CCP), acute phase reactants, symptom duration >6 weeks
- C) Positive ANA only
- D) Erosions on X-ray required for diagnosis
- What is the significance of anti-CCP antibodies?
- A) Non-specific inflammatory marker
- B) Highly specific for RA (>95%), associated with erosive disease and worse prognosis
- C) Rules out RA when negative
- D) Indicates infection
- What is the first-line DMARD for rheumatoid arthritis?
- A) Prednisone
- B) Methotrexate
- C) NSAIDs
- D) Biologic agents
- What monitoring is required for methotrexate therapy?
- When should biologic DMARDs be considered?
Answers
- B) 2010 ACR/EULAR criteria: joint involvement, serology (RF/anti-CCP), acute phase reactants, symptom duration >6 weeks - Classification criteria (score ≥6/10):
- Joint involvement (0-5 points): Number and size of involved joints
- Serology (0-3 points): RF and anti-CCP negative, low positive, or high positive
- Acute phase reactants (0-1 point): Normal or abnormal CRP/ESR
- Duration (0-1 point): <6 weeks or ≥6 weeks
- B) Highly specific for RA (>95%), associated with erosive disease and worse prognosis - Anti-CCP significance:
- Specificity >95% for RA
- Can be positive years before symptom onset
- Associated with more aggressive, erosive disease
- RF is less specific (also elevated in infections, other autoimmune diseases, healthy elderly)
- Double-positive (RF+ and anti-CCP+) indicates highest risk
- B) Methotrexate - Treatment approach:
- Methotrexate is first-line DMARD (disease-modifying antirheumatic drug)
- Start 10-15 mg weekly, titrate to 25 mg weekly
- Add folic acid 1 mg daily to reduce side effects
- Bridge with low-dose prednisone (≤10 mg/day) while DMARD takes effect
- NSAIDs for symptomatic relief but do not modify disease
- Methotrexate monitoring:
- Baseline: CBC, CMP (liver, kidney function), hepatitis B/C serologies, chest X-ray
- Ongoing: CBC, CMP every 2-4 weeks initially, then every 8-12 weeks when stable
- Watch for: Hepatotoxicity (elevated LFTs), bone marrow suppression (cytopenias), pulmonary toxicity (pneumonitis)
- Contraindications: Pregnancy (teratogenic), significant liver disease, significant renal impairment
- Avoid alcohol; supplement with folic acid
- Indications for biologic DMARDs:
- Inadequate response to methotrexate (after 3-6 months at optimal dose)
- Intolerance to methotrexate
- High disease activity with poor prognostic factors (high anti-CCP, erosions, functional impairment)
- Options: TNF inhibitors (etanercept, adalimumab, infliximab), IL-6 inhibitors (tocilizumab), JAK inhibitors (tofacitinib), B-cell depleting (rituximab), T-cell costimulation blocker (abatacept)