Rheumatoid arthritis

• Chronic symmetrical arthritis affecting mainly peripheral joints
• In addition it has non articular features

 

Aetiology

• Most common age of onset is 30-50
• Women before the menopause are 3 times more likely to be affected than men. After then menopause the frequency of onset is the same
• Familial component
• Associated with HLA-DR4 and HLA-DRb1

 

Immunology

• T cell mediated
• Temporary B cell ablation induces remission – suggesting the role of rheumatoid factor is producing and maintaining inflammation
• Antibodies against TNF and IL-1 produce short term improvement in synovitis
• High affinity antibody production is not a feature

 

Pathology

• Widespread synovitis
• Role of rheumatoid factor by plasma cells in the synovium and local formation of immune complexes
• Synovium becomes greatly thickened and becomes palpable as a ‘boggy’ swelling around joints and tendons
• Synovium proliferates into folds and frounds and is infiltrated with neutrophils, macrophages, T cells and B cells
• Form disorganised lymphoid structures
• Increased permeability of blood vessels and synovial lining leads to joint effusions
• Synovium spreads from the joint margins onto the cartilage surface, damaging it by blocking it normal nutrition
• Contributes to juxta-articular osteoporosis
• Rheumatoid factor – IgM recognising the Fc region of IgG
• Aggregate into immune complexes and activated complement

 

Clinical features

• Typically presents as a slowly progressive, symmetrical peripheral polyarthritis evolving over weeks to months
• Patients who develop quickly with a severe symmetrical polyarthritis have a better prognosis

 

DDx

• Postviral arthritis – rubella, hep B or parvovirus
• Seronegative spondyloarthopathy
• Polymyalgia rheumatica
• Acute nodal osteoarthritis

 

Symptoms/signs

• Pain and stiffness of the small joints of the hand and feet
• Wrists, elbows, shoulders, knees and ankles are also affected
• Hips are rarely affected
• Pain and stiffness worse in the morning
• Joints are usually warm and tender with some swelling

 

Complications

• Ruptured tendons
• Ruptured joints
• Joint infections
• Spinal cord compression
• Amyloidosis

 

Joint involvement

 

Hands and wrists

• In early disease fingers and swollen painful and stiff
• Inflamed flexor tendon sheaths may cause carpal tunnel syndrome
• Joint damage results in ulnar drift and palmer subluxation of the MCP
• PIP joint deformities include fixed flexion – Boutonniere deformity or fixed extension – Swan-neck deformity
• Dorsal subluxation of the ulnar styloid may cause rupture of the finger extensor tendons leading to a sudden onset of finger drop in the ring and little fingers

 

Shoulders

• Commonly affected
• Initially mimic rotator cuff tendonitis with painful arc syndrome and pain in the upper arms at night
• Stiffening occurs as the joint becomes more damaged
• Rotator cuff tears are common

 

Elbows

• Swelling and painful fixed flexion deformities

 

Feet

• Painful swelling of the MTP joints
• Foot becomes broader and hammer toe deformity develops
• Pain is caused by exposure of the metatarsal heads due to movement of protective fibro-fatty pad
• Flat medial arch and loss of flexion of the foot
• Ankle assumes valgus formation

 

Knees

• Synovitis and effusion
• Risk of popliteal cyst formation and rupture
• Erosion of cartilage and bone causes loss of joint space and damage to the medial/lateral/retropatellar compartments
• Knees may develop valgus or varus deformity
• Secondary OA follows

 

Cervical spine

• Synovitis may affect the synovial joints of the upper cervical spine and the bursae which separates the ondontoid peg from the anterior arch or the atlas
• May cause atlanto-axial or upper cervical instability
• May result in damage to the spinal cord resulting in pyramidal and sensory signs

 

Nonarticular manifestations

 

Soft tissue surrounding joints

• Subcutaneous nodules, firm, intradermal and generally occur over pressure points
• May ulcerate and become infected
• May can bursitis of the olecranon
• Tenosynovitis of the flexor tendons of the hand can cause finger trigger
• Muscle wasting of the hands – corticosteroid induced myopathy may occur

 

Lungs

• Peripheral intrapulmonary nodules are usually asymptomatic but may cavitate
• When pneumoconiosis in present (Caplan’s syndrome), large cavitating lung nodules develop

 

Vasculitis

• Caused by immune complex deposition in the blood vessel walls
• Manifestations include;
• Nail-fold infarcts due to cutaneous vasculitis
• Cutaneous vasculitis with skin necrosis
• Mononeuritis multiplex
• Bowel infarction

 

Heart and peripheral vessels

• Pericarditis
• Endocarditis
• Myocardial disease
• Raynaud’s syndrome

 

Spleen, lymph nodes and blood

• Felty’s syndrome is splenomegaly and neutropenia in a patient with RA
• May be peripheral lymphadenopathy
• Anaemia is common and is the normochromic, normocytic anaemia of chronic disease

 

Investigations

• Blood counts – anaemia may be present, raised inflammatory markers
• Serology – rheumatoid factor and ANA
• X-rays of affected joints
• Aspiration of joint

 

Criteria for diagnosis of rheumatoid disease

• Four or more criteria required for diagnosis
  • Morning stiffness >1hr for 6 weeks or more
  • Arthritis of 3 or more joints for 6 weeks or more
  • Arthritis of wrists and hands for 6 weeks or more
  • Symmetrical arthritis
  • Subcutaneous nodules
  • A positive serum rheumatoid factors
  • Typical radiological changes  - erosions or periarticular osteopenia

 

Management

• 25% of patients will recover completely
• Use NSAIDs and analgesics to control symptoms
• Try to induce remission with im depot of methylprednisolone if synovitis persists
• Treat recurrence of synovitis with sulfasalazine or methotrexate
• Give second i.m depot of methylprednisolone
• Refer for physiotherapy
• If no significant improvement give methotrexate with sulfasalazine
• If no improvement, use gold, d-penicillamine, leflunamide or anti-TNF

 

• Use of DMARDs early in disease prevent long term irreversible damage of the joints
• DMARDs may act through cytokine inhibition
• Include;
  • Methotrexate
  • Sulfasalazine
  • Leflunamide (blocks pyrimidine production in proliferating lymphocytes by blocking dyhydro-orotate dehydrogenase). Shouldn’t be used in premenopausal women
  • TNF blocker
  • ciclosporin