Rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disorder characterized by symmetrical polyarthritis and may involve extra-articular systems. It leads to joint destruction and functional disability if untreated.

Epidemiology

• Incidence: Approximately 1-3 per 1,000 people annually.
• Prevalence: Affects about 0.5% to 1% of the adult population, more common in women (3:1 ratio).
• Age of Onset: Typically develops between ages 30 and 60.

Etiology

1. Genetic Factors:
   • HLA-DRB1: Specific alleles increase susceptibility.
   • Family history of RA or autoimmune disorders.
2. Environmental Triggers:
   • Smoking: Increases risk, particularly in genetically predisposed individuals.
   • Infections: Viral infections (e.g., Epstein-Barr virus) may act as triggers.
3. Hormonal Influences: Increased prevalence in women suggests hormonal roles.

Pathophysiology

• Autoimmune Mechanism: The immune system targets the synovium, leading to chronic inflammation.
• Cytokine Release: Pro-inflammatory cytokines (TNF-α, IL-1, IL-6) drive inflammation and joint damage.
• Pannus Formation: Hyperplastic synovial tissue invades cartilage and bone, leading to destruction.

Clinical Features

1. Joint Symptoms:
   • Symmetrical Polyarthritis: Affects small joints (hands, wrists, feet) initially, progressing to larger joints.
   • Morning Stiffness: Lasts over 30 minutes, improving with activity.
   • Swelling and Tenderness: Affected joints are warm, swollen, and tender.
2. Extra-Articular Manifestations:
   • Rheumatoid Nodules: Firm subcutaneous nodules over extensor surfaces.
   • Pulmonary Involvement: Interstitial lung disease, pleuritis.
   • Cardiovascular Complications: Increased risk of atherosclerosis and pericarditis.
   • Ocular Manifestations: Scleritis and dry eyes (secondary to Sjögren’s syndrome).

Diagnosis

1. Clinical Assessment: Comprehensive history and physical examination.
2. Laboratory Tests:
   • Rheumatoid Factor (RF): Positive in approximately 70-80% of cases.
   • Anti-Citrullinated Protein Antibodies (ACPA): Present in 60-70% of cases, more specific for RA.
   • ESR and CRP: Elevated levels indicate inflammation.
   • Complete Blood Count (CBC): May show anemia of chronic disease.
3. Imaging Studies:
   • X-rays: Show erosions and joint space narrowing over time.
   • Ultrasound and MRI: Useful for detecting early synovitis and guiding treatment.

Management

Pharmacologic Treatment

1. Non-Steroidal Anti-Inflammatory Drugs (NSAIDs):
   • Ibuprofen: 400-800 mg orally every 6-8 hours as needed (max: 3200 mg/day).
   • Naproxen: 250-500 mg orally twice daily (max: 1500 mg/day).
2. Disease-Modifying Anti-Rheumatic Drugs (DMARDs):
   • Methotrexate:
     • Dosage: Start with 7.5 mg orally once weekly; may increase to 15-25 mg/week based on response.
     • Monitoring: Liver function tests (LFTs), CBC for leukopenia, and renal function.

1. Other DMARDs: Leflunomide, sulfasalazine, and hydroxychloroquine may be used as alternatives or in combination.
2. Biologic Agents:
   • Target specific components of the immune response:
     • TNF Inhibitors: Etanercept, infliximab, adalimumab.
     • Non-TNF Inhibitors: Abatacept (CTLA-4 inhibitor), rituximab (anti-CD20 monoclonal antibody), tocilizumab (IL-6 receptor antagonist).
   • Typically reserved for patients with inadequate response to DMARDs..

3. Corticosteroids:
   • Prednisone:
     • Dosage: 5-10 mg orally daily as needed for symptom control.
     • Use: Short-term control of flares, often in conjunction with DMARDs.

Non-Pharmacologic Treatment

1. Physical Therapy: Customized exercise programs to maintain joint function and flexibility.
2. Occupational Therapy: Strategies to manage daily activities and conserve energy.
3. Patient Education: Informing patients about RA, self-management strategies, and the importance of adherence to treatment.
4. Dietary Changes: A Mediterranean diet rich in omega-3 fatty acids may have anti-inflammatory effects.

Surgery

• Indications: For severe joint damage or cases unresponsive to medical management.
• Procedures:
  • Synovectomy: Removal of inflamed synovial tissue to relieve pain and improve function.
  • Joint Replacement: Total joint arthroplasty may be indicated for severely damaged joints (e.g., knees, hips).

Complications

1. Joint Destruction: Progressive erosive changes leading to deformities and loss of function.
2. Cardiovascular Disease: Increased risk of heart disease and stroke due to chronic inflammation.
3. Osteoporosis: Higher risk of fractures, particularly in patients receiving long-term corticosteroid therapy.
4. Felty’s Syndrome: A triad of RA, splenomegaly, and neutropenia.

Prognosis

• Variability: Disease progression varies; some patients achieve remission, while others may have chronic, progressive disease.
• Early Intervention: Prompt diagnosis and aggressive treatment improve long-term outcomes and reduce joint damage.