Internal MedicineRheumatologyRheumatoid Arthritis

Rheumatoid Arthritis

Must-Not-Miss / Red Flags

  • Cervical spine involvement: atlantoaxial subluxation – risk of cord compression
  • Systemic vasculitis: mononeuritis multiplex, skin ulcers
  • Fever and serositis: may indicate severe disease flare or infection
Patient Explanation
“Your immune system is mistakenly attacking your joints, causing pain and swelling. Modern medicines can control the inflammation and prevent joint damage.”
Board Fact
“Anti‑citrullinated protein antibodies (ACPA) are highly specific (>95%) for RA and predict more aggressive disease.”
ICD-10
M05.9

Definition & Core Concept

Rheumatoid arthritis (RA) is a chronic, systemic autoimmune disease characterized by symmetrical polyarthritis, primarily affecting small joints, leading to progressive destruction of cartilage and bone if untreated.

Epidemiology & Risk Factors

  • Prevalence ~1% worldwide, female‑to‑male ratio 3:1
  • Peak onset age 30‑60 years
  • Genetic association with HLA‑DR4 and HLA‑DR1
  • Smoking is the strongest environmental risk factor

Pathophysiology (Rule of 3)

  1. Genetic susceptibility + environmental trigger (smoking) → citrullination of peptides
  2. Loss of self‑tolerance → T‑cell and B‑cell activation → autoantibody production (RF, ACPA)
  3. Synovial inflammation → pannus formation → cartilage and bone erosion

Clinical Presentation

  • Symmetrical polyarthritis of MCP, PIP, wrists, and MTP joints
  • Morning stiffness >1 hour, improves with activity
  • Extra‑articular: rheumatoid nodules, interstitial lung disease, pericarditis, Sjögren’s

Diagnostic Workup

RF and ACPA: seropositive in 70‑80%. CRP/ESR: elevated. X‑ray: periarticular osteopenia, marginal erosions, joint space narrowing. Ultrasound/MRI: detects early synovitis and erosions before X‑ray changes.

Management Protocol

  1. DMARDs: Methotrexate is first‑line (15‑25 mg/week + folic acid). Start within 3 months of diagnosis.
  2. Biologics: TNF‑α inhibitors (Adalimumab, Etanercept) if inadequate response to MTX
  3. NSAIDs and corticosteroids: for symptom control during flares
  4. Treat‑to‑target: aim for remission or low disease activity (DAS28 <3.2)
  5. Physical therapy and occupational therapy

Complications & Prognosis

  • Joint deformity: ulnar deviation, swan‑neck, boutonnière deformities
  • Carpal tunnel syndrome
  • Accelerated atherosclerosis (chronic inflammation) → increased CV mortality
  • Interstitial lung disease (RA‑ILD)

ICU Criteria

ICU admission rarely required unless severe systemic vasculitis or fulminant RA‑ILD with respiratory failure.

Clinical Vignette

A 45‑year‑old woman complains of 3 months of morning stiffness lasting 2 hours, with pain and swelling in both hands and wrists. Examination reveals synovitis of MCP and PIP joints. RF and ACPA are positive.

Pearls & Pitfalls

  • Early aggressive treatment with DMARDs is critical – the “window of opportunity” is within 3‑6 months of symptom onset.
  • Always screen for latent TB before starting biologics (TNF‑α inhibitors).

Discharge & Follow-Up

Regular monitoring of disease activity (DAS28), liver function (MTX), and screening for cardiovascular risk factors. Annual ophthalmology exam if on hydroxychloroquine.

Literature & Guidelines

ACR 2024 Guideline for the Treatment of Rheumatoid Arthritis. PMID: 36350801.

Personal Clinical Notes