Rheumatoid Arthritis

Definition

• systemic inflammatory disease
• most marked changes are in the synovium of tendons & joints

characterised by:

• chronic, symmetrical polyarthritis/synovitis
• morning stiffness
• raised ESR
• RF (anti IgG & IgM AB’s) - 60-80%

Rheumatic disorders

• group of disorders that cause pain, stiffness & swelling around joints & ligaments
• characterised by
• chronicity
• local & systemic features of inflammation
• all d/t abN immune mechanism

Incidence

• affects approx. 3% of population
• usually starts in 4th decade
• 3X more common in females
• less frequent in blacks in RSA

Etiology

• unknown
• may be a genetic predisposition
  • more common in HLA-CW3 & HLA-DW4 histo-compatibility antigens
• a virus which stimulates immune response
  • presence of Ag-Ab complexes in the joint after Cx activation
• susceptibility affected by
  • age, sex, hormones (<< in pregnancy), diet & stress

Pathology

• mostly synovium affected
• pathognomonic lesion - rheumatoid nodule
• 3 pathological stages

Joints & tendons

Stage 1 - synovitis & joint swelling

• vascular proliferation
• synovial proliferation - villus formation -> pannus (granulation tissue)
• potentially reversible

stage 2 - joint & tendon destruction with periarticular erosion

• cartilage erosion d/t proteolytic enzymes & direct invasion by pannus
• peri-articular bone erosion
• similar changes in tendon sheaths -> partial or complete rupture

stage 3 - joint destruction & deformity

• d/t articular destruction + capsular stretching + tendon rupture
• result in instability & deformity

2. Extra-articular tissues

• Systemic dx.
• Rheumatoid nodules
  • central necrotic zone surrounded by histiocytes & granulation tissue
  • found in skin (esp. over bony prominences), synovium, tendons, sclera & viscera
  • dorsum of hand / elbow
• Lymphadenopathy
• Splenomegaly
  • Felty sy. - splenomegaly, lymphadenopathy, arthritis
• Vasculitis
• Muscle weakness
  • myopathy or neuropathy
• Myelopathy - spinal cord involvement
• Sensory changes
  • Sensory changes
• Visceral changes
  • lungs, heart, kidneys, brain & GIT
• Skin atrophy

Clinical features

• general symptoms
  • malaise, tiredness, weight loss
  • myalgia

Early stages

• symmetric polysynovitis
  • mostly prox. joints of hands & feet, wrists, ankles, knees & shoulders
  • swelling, thickening & tenderness of synovium
• tenosynovitis
  • extensors of wrist & flexors of fingers
  • thickening, tenderness & crepitus
• stiffness
  • early morning or after inactivity

Later stages

• joint deformity, destruction & instability
  • radial deviation & volar subluxation of carpus d/t ruptured FCU
  • ulnar drift of fingers
  • loss of elbow extension d/t thickening of capsule, nodules
  • valgus knees
  • valgus feet & claw toes
• C-spine abnormalities
• extra-articular features
  • weakness & wasting of muscles
  • lymphadenopathy
  • skin atrophy

Investigations

Blood tests

• normocytic normochromic anaemia - abN erythropoeisis d/t dx.
• raised ESR & CRP
• RF +ve (80% of cases)
• ANF +ve in 30%
• none of these tests are specific or needed for the diagnosis

Synovial biopsy

• most features are non-specific

X rays

• early - soft tissue swelling & peri-articular osteopenia
• later - marginal erosions & decreased joint space (proximal joints of hands & feet, AC joint, wrists)
• advanced dx. - joint destruction & deformity
• must get flexion-extension views of C-spine

Diagnosis

Minimal criteria - 4 out of 7

1. bilateral symmetrical polyarthritis
2. present for > 6 weeks
3. morning stiffness
4. subcutaneous nodules
5. X-ray signs of peri-articular erosions
6. more than 4 joints involved
7. proximal joints of hands or feet

• +ve RF w/out above doesn’t = RA - negative RF doesn’t exclude RA
  • 20% of patients with RA are RF -ve (sero-negative RA)
• value of RF - high titers -> more serious dx.
• increasing age - >> percentage of patients test positive
• conditions in which RF may be +ve:
  • adult RA
  • Sjogren’s syndrome
  • SLE
  • scleroderma
  • mixed connective tissue disease
  • polymyositis
  • acute viral infections - infectious mononucleosis, infectious hepatitis, influenza, rubella
  • chronic inflammatory diseases - TB, syphilis
  • neoplasms
  • miscellaneous - elderly normal people, sarcoidosis, chronic active hep., post-transfusion
• diagnosis of RA is essentially clinical - can not be made without objective physical signs

Differential dg.

• seronegative arthritis - Reiter’s dx., psoriatic etc.
• Heberden’s arthropathy (OA) - distal IP joints
• ankylosing spondylitis - mainly dx. of axial skeleton
• polyarticular gout - big & small joints, tophi
• CPPD dx. - calcifications in joints, big joints (knees, shoulders )
• sarcoidosis - symmetrical small joint polyarthritis (Kveim test or ACE levels), scleroderma nodosum
• polymyalgia rheumatica - post inactivity stiffness, pelvic & pectoral girdle weakness

Treatment

• no cure
• multidisciplinary approach

4 principles

Stop synovitis

• rest & splinting
• NSAIDs
• disease modifying drugs
• gold, penicillamine, chloroquine, immuno-suppressive drugs

Indications

• uncontrolled synovitis - despite low dose steroids & NSAIDs
• erosions on plain films of the hands & feet in a patient with active synovitis
  • side effects - kidney, liver, haemopoetic system
  • take 6-12 weeks before effect seen
  • low dosage initially
  • monitor FBC, U&E, LFT

Systemic steroids

• relieve joint pain & stiffness
• side effects - OP, HT, DM, infections

Intra-synovial injections

• HCI, cytotoxics (nitrogen mustard), Yttrium-90

Synovectomy

• indications
  • no response to 6/12 conservative Rx.
  • good ROM
  • no x-ray changes / destruction
• open or arthroscopic
• major indication - extensor teno-synovectomy for prophylaxis of extensor tendon rupture

Prevent deformity

• splint
• physiotherapy
  • full range of passive movements daily - maintain ROM
  • maintain muscle power
• postural training
• surgery
  • repair of tendon rupture - suture, transfer (especially hand & wrist)
  • joint instability - soft tissue stabilisation of wrist of finger joints
  • bony procedures - e.g. excision of radial head, distal ulna, MT heads

Principles

• X-ray of C-spine always before GA
• worst deformity 1st
• always wrist before fingers
• lower limb before upper limb, hip before knee
• start with a winner - i.e. likely to give good result

Reconstruct

• with advanced joint destruction
• arthrodesis
  • shoulder (rare), wrist, finger joints, ankle & sub-talar joints, C-spine
• excision
  • radial head, distal ulna, MT heads
• replacement
  • shoulder, elbow, hip, knee & MPJ’s & IPJ’s

Rehabilitate

Complications

• fixed deformities
• muscle weakness, wasting - neuro / myopathy
• joint capsule rupture
• infection - especially if on steroids
• spinal cord compression - C-spine
• systemic vasculitis
• amyloidosis - progressive renal failure

Prognosis

• variable course
• difficult to predict
• 10% completely disabled
• bad prognosis
• in females
• if starts at early age
• if high RF titers
• vasculitis, joint erosions, contractures & wasting