TB

Orthopaedic Infections

Tuberculosis

Western Health Orthopaedic Registrar presenation – Tuberculosis in Orthopaedics by Dr David Slattery

  • Joints Affected(decreasing order)
    • Spine
    • Knee
    • Hip
    • Ankle
    • Wrist
    • SIJ
    • Pubic symphysis
    • Small bones hand & foot

Epidemiology

  • 1.9 billion
  • 3 million deaths per yerar
  • ¾ = sub-Saharan Africa & s-e Asia
  • Industrialised nations
    • Increase during 80’s & early 90’s
    • Relative ↑ in extrapulmonary disease

Pathology

  • Entry via lung (droplet) or GIT or skin

Primary complex

  • usually lung, pharynx or gut
  • Regional node involvement
  • Minimal clinical effect
  • Within nodes bacilli may be dormant for years
  • Body sensitized to infection
  • therefore a reactivation leading to destructive processes

Secondary Spread

  • Bloodborne dissemination
  • Miliary TB or meningitis
  • Once destructive lesions arise leading to tertiary lesions

Tertiary Lesions

  • 5% of TB
    • bone or joint
  • Chronic inflammatory reaction

History

  • Long history
  • Monoarticular
  • Marked synovial thickening
  • Marked muscle wasting
  • Periarticular osteoporosis

Investigations

  • Positive Mantoux test
  • WCC
    • may be normal
  • ESR
    • may be normal
    • In exudative form there is usually elevation of markers
  • Tuberculin test
    • 80 – 90 % positive
    • Allergic inflammatory reaction to purified protein derivative (PPD) antigen
    • Positive reponse
      • infected at some stage but not necessarily current

Microscopy

  • Acid fast bacilli
  • 5 – 30 days for culture growth
  • Characteristic Langhan’s giant cells in granuloma
  • Caseous necrosis
  • Epiphysis is not a barrier
  • Synovium thickened
  • Caseation
    • cold abscess

Orthopaedic Manifestations

Bones

  • Rarely originates in a long one
  • Metaphyseal foci can occur in children
  • May originate in epiphysis & spread into adjacent joint

Tuberculous dactylitis

  • multiple soft tissue swellings of digits
  • Diffuse lytic areas of phalanges & metacarpals
  • Periostitis

Tuberculous Arthritis

  • Subchondral osteoporosis
  • Cystic changes
  • Narrowed joint space
  • Differential Diagnosis
    • RA, PVNS, RSD

Spinal Tuberculosis

Treatment

  • Improve general health
  • Immobilise as required
  • Drainage often not necessary
  • Chemotherapy regimens often change
    • Isoniazid, Rifampin, Ethambutol, Pyrazinamide, Streptomycin
    • Usually four drugs because of risk of resistance

Early disease

  • Drug therapy
  • Joints splinted, mobilised as disease signs diminish
  • If persistent joint irritation, effusion, synovitis » washout, synovectomy permits better drug access

Arthrodesis

  • Rarely required in tuberculous arthritis
  • Previously used (pre antibiotics) to reduce flareups