Tuberculosis of the Spine

Definition & Epidemiology

Tuberculosis of the spine (Pott’s disease) is the commonest and most dangerous form of skeletal tuberculosis. It is caused by Mycobacterium tuberculosis reaching the vertebra haematogenously (usually from a pulmonary or other focus). The thoracolumbar region is most often affected. It is important because of the risk of vertebral collapse, deformity and paraplegia.

Pathology

Infection typically begins in the paradiscal region of the vertebral body. Caseating granulomatous destruction spreads to involve the disc (narrowing) and adjacent vertebrae. Anterior vertebral body collapse produces the characteristic angular kyphosis (gibbus / knuckle deformity). Caseous material and pus form a cold abscess (no heat or redness, unlike a pyogenic abscess) that tracks along fascial planes under gravity — e.g. A psoas abscess presenting in the groin.

Pott’s spine: paradiscal destruction and anterior wedge collapse cause an angular kyphosis (gibbus); a cold abscess tracks distally along fascial planes.

Clinical Features

Insidious back pain and stiffness with constitutional symptoms — evening rise of temperature, night sweats, weight loss, malaise. There may be a visible/palpable gibbus, muscle spasm, a cold abscess, and — most seriously — signs of cord compression (Pott’s paraplegia): weakness, sensory level, bladder/bowel involvement and upper-motor-neuron signs.

Investigations

• Radiographs show paradiscal erosion, reduced disc space, vertebral collapse and a paravertebral (fusiform) soft-tissue shadow.
• MRI is the investigation of choice — it shows marrow oedema, abscesses, disc and cord involvement early. Raised ESR
• a positive Mantoux/IGRA supports the diagnosis.
• CT-guided biopsy for histology (caseating granuloma) and culture/GeneXpert confirms the diagnosis and drug sensitivity.

Management

The mainstay is anti-tuberculous chemotherapy — standard multi-drug therapy (isoniazid, rifampicin, pyrazinamide and ethambutol in the intensive phase, then continuation), given for a prolonged course (commonly 9–18 months for spinal TB). Most patients respond to drugs plus rest/bracing. Surgery is indicated for neurological deficit (cord compression), a large abscess, instability or severe/progressive deformity, and failure of medical treatment — decompression, abscess drainage and stabilisation (e.g. Anterior debridement and fusion). Nutrition and general care are important.

• Commonest skeletal TB; thoracolumbar; begins in the paradiscal vertebral body.
• Anterior collapse → angular kyphosis (gibbus); cold abscess tracks along fascial planes.
• Constitutional symptoms + back pain; MRI is the imaging of choice; biopsy confirms.
• Pott’s paraplegia: early-onset (better prognosis) vs late-onset.
• Mainstay = multi-drug ATT (9–18 mo); surgery for deficit, abscess, instability or deformity.