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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

1. 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
    • neuropathy or compression by thickened synovium
  • 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.

  1. seronegative arthritis - Reiter’s dx., psoriatic etc.
  2. Heberden’s arthropathy (OA) - distal IP joints
  3. ankylosing spondylitis - mainly dx. of axial skeleton
  4. polyarticular gout - big & small joints, tophi
  5. CPPD dx. - calcifications in joints, big joints (knees, shoulders )
  6. sarcoidosis - symmetrical small joint polyarthritis (Kveim test or ACE levels), scleroderma nodosum
  7. 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