Makindo Medical Notes

Related Subjects: |Polyarticular arthritis |Rheumatoid arthritis |Systemic Sclerosis (Scleroderma) |RA vs OA |Acute and Chronic Gout |Calcium Pyrophosphate Deposition (Pseudogout) |Osteoporosis |Rheumatology Autoantibodies

Rheumatoid Arthritis (RA) is a chronic, symmetrical polyarthritis characterized by persistent synovitis, joint deformities, and systemic features. Symptoms should persist for over 6 weeks before a diagnosis is confirmed. Anti-CCP antibodies serve as an early and specific marker for RA.

About

• RA affects about 1% of the population, with a higher prevalence in females (3:1 ratio).
• The hallmark symptom is early morning stiffness lasting more than 60 minutes, often indicating active disease.
• Joint involvement is typically symmetrical, affecting the PIP and MCP joints, as well as large joints like the knees and shoulders.

Aetiology

• Genetic predisposition with associations like HLA-DR4 (60%) and genes like PTPN22, STAT4, and PADI-4.
• Environmental factors, such as smoking, increase the risk of seropositive RA.
• Hormonal influences include increased incidence postpartum and during breastfeeding.
• Presence of rheumatoid factor (RF) and anti-cyclic citrullinated peptide (Anti-CCP) antibodies indicate a more aggressive disease course.

Pathology

• RA primarily targets the synovium, causing synovitis, hyperplasia, and pannus formation, which invades and destroys cartilage and bone.
• Rheumatoid nodules, common in RF-positive cases, consist of granulomas with fibrinoid necrosis and palisaded histiocytes.

Rheumatoid Lung: A complication of RA involving pulmonary nodules and interstitial fibrosis.

Clinical Features (Symptoms > 6 weeks)

• Systemic: Fatigue, low-grade fever, weight loss, anemia of chronic disease.
• Skin/Eyes:
  • Dry eyes (keratoconjunctivitis sicca) and dry mouth (xerostomia).
  • Scleritis (red, painful eye), episcleritis, scleromalacia (painless thinning).
• Joints:
  • Symmetrical involvement of wrists, elbows, shoulders, knees, and small joints (MCP/PIP).
  • Joint pain, swelling, and tenderness; often sparing the DIP joints.
  • Hand deformities like ulnar deviation, swan neck, and Boutonniere deformities.
  • Feet: Subluxation of MTP joints, flat feet from tibialis posterior tendon rupture.
• Cardiopulmonary: Pericarditis, pleural effusions, interstitial lung disease, increased risk of cardiovascular events.
• Vasculitis: Ulcers, mononeuritis multiplex, gangrene in severe cases.
• Neurological: Atlantoaxial subluxation, peripheral neuropathy, carpal tunnel syndrome.
• Renal: Amyloidosis leading to nephrotic syndrome; risk of NSAID-related nephropathy.

Investigations

• Blood Tests:
  • FBC: Normochromic normocytic anemia, thrombocytosis, leukopenia (Felty's syndrome).
  • Raised ESR/CRP indicates active disease.
  • Rheumatoid factor (RF) and Anti-CCP antibodies (more specific for RA).
  • LFTs and U&E to monitor for medication toxicity.
• Joint Aspiration: Excludes infection; typically shows increased neutrophils and protein levels.
• Imaging:
  • X-rays: Early soft tissue swelling and osteopenia, later joint space narrowing and erosions.
  • MRI: More sensitive in detecting early erosions and synovitis.
  • Lateral neck X-rays for cervical spine instability.

Management

• Goals: Prevent joint damage, reduce inflammation, and maintain function.
• DMARDs: Start early to alter disease course.
  • Methotrexate (anchor drug): 7.5-30 mg weekly, avoid in pregnancy.
  • Sulfasalazine: Useful for mild disease and women planning pregnancy.
  • Leflunomide, Hydroxychloroquine (eye exams required), Azathioprine.
• Biologics: Consider for moderate-severe cases or those unresponsive to DMARDs.
  • TNF inhibitors (e.g., etanercept, infliximab), IL-6 receptor blockers (e.g., tocilizumab).
  • Rituximab (targets CD20 B-cells), Abatacept (T-cell co-stimulation blocker).
• Non-Medical: Physiotherapy, occupational therapy, splinting, joint protection strategies.
• NSAIDs: Symptomatic relief but do not alter disease progression.
• Steroids: Low-dose oral or intra-articular injections during flares; monitor for side effects.
• Surgery: Synovectomy, joint replacement to relieve pain and improve function in advanced cases.

Prognosis and Monitoring

• Poor Prognostic Indicators: Early joint damage, high RF/anti-CCP titers, systemic involvement, HLA-DR4, > 20 joint involvement.
• Monitoring: Regular blood tests (FBC, LFTs) for DMARD toxicity, imaging for disease progression, and functional status assessments.

References

• Diagnosis and Management of Rheumatoid Arthritis