Define Rheumatoid Arthritis. Describe its clinical features, investigations, management and complications.

Definition

Rheumatoid arthritis (RA) is a chronic, systemic autoimmune inflammatory disease characterised by a symmetrical, deforming polyarthritis that primarily attacks the synovium of small and large joints, together with extra-articular manifestations. It affects women more than men and typically begins in the third to fifth decades.

Pathology

The hallmark is synovitis: the inflamed, proliferating synovium forms a pannus — a mass of vascular granulation tissue that spreads over and erodes articular cartilage and subchondral bone from the joint margins, and stretches or destroys the capsule, ligaments and tendons. This leads progressively to joint destruction, instability and the characteristic deformities.

Clinical Features

Insidious onset of symmetrical pain, swelling and stiffness of the small joints of the hands and feet — typically the MCP, PIP and wrist joints (sparing the dip joints) — with prolonged early-morning stiffness (> 1 hour) and systemic features (fatigue, malaise, low-grade fever). Established disease produces characteristic hand deformities: ulnar deviation of the fingers, swan-neck and boutonnière deformities, Z-thumb, and volar subluxation at the wrist.

Extra-articular Features

RA is a systemic disease: rheumatoid nodules (over pressure points), anaemia, vasculitis, lung involvement (nodules, fibrosis, effusions), eye disease (episcleritis, scleritis, dry eyes in secondary Sjögren’s), pericarditis, and, importantly for orthopaedics, cervical spine (atlanto-axial) instability.

Investigations

Serology: rheumatoid factor and anti-CCP antibodies (more specific), raised ESR/CRP, and a normochromic normocytic anaemia. Radiographs show peri-articular osteoporosis, soft-tissue swelling, marginal erosions, joint-space narrowing and, later, deformity and subluxation. The diagnosis uses the ACR/EULAR classification criteria.

Management

Management is by a rheumatology-led multidisciplinary team aiming for early control (‘treat to target’). The mainstay is disease-modifying anti-rheumatic drugs (DMARDs) — methotrexate first-line — started early, with biologic agents (anti-TNF and others) for resistant disease. NSAIDs and short courses of corticosteroids control symptoms and flares. Physiotherapy, occupational therapy and orthoses preserve function. Surgery (synovectomy, tendon repair, joint replacement or arthrodesis) is reserved for pain, deformity or loss of function despite medical treatment.

Complications

Beyond joint destruction and deformity, patients face the complications of chronic inflammation and its treatment: accelerated cardiovascular disease (the leading cause of excess mortality), osteoporosis (disease- and steroid-related), secondary amyloidosis, increased infection risk from immunosuppression, and cervical (atlanto-axial) instability. Regular monitoring of disease activity, drug toxicity and cardiovascular risk is an integral part of care.

Symmetrical small joint involvement with morning stiffness over an hour.

• Chronic systemic autoimmune synovitis; symmetrical small-joint polyarthritis; F>M.
• Pannus erodes cartilage/bone; MCP/PIP/wrist affected, dip spared; >1 h morning stiffness.
• Deformities: ulnar deviation, swan-neck, boutonnière, Z-thumb; extra-articular disease common.
• RF/anti-CCP positive, ↑ESR/CRP; marginal erosions & peri-articular osteoporosis on X-ray.
• Early DMARDs (methotrexate) ± biologics; beware atlanto-axial instability before anaesthesia.