Spinal Tuberculosis (Pott’s Disease)

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Spinal tuberulosis or Pott’s disease is a form of tuberculosis affecting the vertebrae. Lower thoracic and upper lumbar vertebrae area are most commonly affected.

Pathogenesis:

  • Hematogenous spread
  • Most commonly originates from pulmonary and genitourinary tuberculosis
  • Involves para discal area commonly
  • Interosseous venous channels take infection to central vertebrae and non-contiguous vertebral body
  • In young disc is involved primarily due to vascularity
  • In old vascularity is reduced so disc is secondarily involved
  • Involvement of central vertebrae leads to collapse-vertebra plana
  • Para discal type leads to loss of inter vertebral space and adjacent vertebrae
  • There is collapse of spinal element and anterior wedging
  • Gibbus formation takes place (palpable deformity due to involvement of multiple vertebrae

Mechanism of paraplegia:

  • Early onset:
    • Mechanical pressure
    • Tuberculous granuloma
    • Tuberculous myelitis
    • Spinal artery thrombosis
    • Tuberculous arachnoiditis
  • Late Onset:
    • Transection of spinal cord by bony bridge
    • Fibrosis of dura

Clinical Features:

  • Local Pain
  • Local tenderness
  • Stiffness and spasm of muscles
  • Cold abscess
    • Local spread to potential spaces and under ligaments
  • Gibbus
  • Spinal deformity
    • Loss of curve
    • Kyphosis
    • Scoliosis
  • Constitutional symptoms:
    • Malaise
    • Weight loss
    • Loss of appetite
    • Night sweats
    • Evening rise of temperature
    • Generalized body aches and fatigue
A child with bone tuberculosis
A child with bone tuberculosis

Investigations:

  • Blood count:
    • WBCs maybe normal
  • ESR:
    • Raised
  • Biopsy:
    • Sample:
      • Bone
      • Abscess (CT-guided)
    • Tests:
      • Staining
      • Culture and sensitivity
      • Histology
    • Tests for pulmonary and genitourinary tuberculosis
  • Imaging:
    • X-ray spine:
      • Rarefaction of vertebral end plates
      • Loss of disk heights
      • Osseous destruction
      • New bone formation
      • Soft tissue abscess
        • Calcification is pathognomic for tuberculous abscess
        • Soft tissues shadows adjacent to spine
      • CT-Scan:
        • Bone destruction
        • Calcification
        • Soft tissue abscess
      • MRI:
        • Soft Tissue involvement
        • Assessment of disc
      • Bone scan

Types of Vertebral Involvement in Spinal Tuberculosis:

  • Para discal:
    • Reduced disk space
  • Central:
    • Vertebra plana
  • Anterior Marginal:
    • Lytic lesion on anterior margin
  • Skipped Lesions:
    • Involvement of two or more vertebrae with intervening normal vertebrae
  • Posterior:
    • Posterior arch involved
    • Rare
  • Synovial:
    • Synovial membranes of atlanto-axial and atlanto-occipital joints

Differential Diagnosis:

  • Pyogenic spondylitis
  • Brucellar spondyltis
  • Sarcoidosis
  • Metastasis
  • Multiple myeloma
  • Lymphoma

Treatment of Spinal Tuberculosis:

  • Multidisciplinary Team involving
    • Neurologist
    • Infectious disease specialist
    • Spinal orthopedics surgeon
    • Physiotherapist
    • Specialized nurse
    • Patient relatives
  • Supportive Care:
    • Bed rest on hard bed
    • Braces and casts (questionable efficacy)
    • Early mobility and exercises
  • Anti tuberculous Treatment:
    • Initiation:
      • 3 months
      • Isoniazid
      • Rifampicin
      • Pyrazinamide
      • Ethambutol/ streptomycin
    • Continuation:
      • 5 months
      • Isoniazid
      • Rifampin

Surgical treatment:

Indications:

Without neurological complications:

  • Progressive bone destruction in spite of anti tuberculous treatment
  • Failure to respond to conservative therapy
  • Evacuation of paravertebral abscess when it has increased in size despite medical treatment
  • Uncertainity of diagnosis for biopsy
  • Mechanical reasons:
    • Spinal instability caused by destruction of collapse
    • Destruction of two or more vertebrae
    • Kyphosis
  • Prevention of severe kyphosis in young children with extensive dorsal lesions
  • Large paraspinal abscess

With neurological complications:

  • New of worsening neural complications or lack of improvement with conservative treatment
  • Paraplegia of rapid onset or severe paraplegia
  • Late onset paraplegia
  • Neural arch disease
  • Painful paraplegia in elderly patients
  • Spinal tumor syndrome (epidural spinal tuberculoma without osseous involvement)
  • Procedures:
    • Posterior decompression and fusion with bone autograft
    • Anterior debridement/decompression and fusion with bone autograft
    • Anterior debridement/decompression and fusion, followed by simultaneous or sequential posterior fusion with instrumentation
    • Posterior fusion with instrumentation followed by simultaneous or sequential anterior debridement/decompression and fusion