Spinal Tuberculosis (Pott's Disease)

Spinal tuberculosis (Pott's disease) is the most common form of skeletal tuberculosis, first described by Percivall Pott in 1779. It represents a significant cause of morbidity, particularly in endemic regions, and remains important in low-incidence high-income settings due to immigration patterns.

Epidemiology:

• Spinal TB accounts for 50% of all skeletal TB cases
• Second most common form of extrapulmonary TB
• Thoracolumbar junction (T10-L2) is most commonly affected
• Approximately 10-15% have skip lesions (non-contiguous involvement)
• Male to female ratio approximately 1.5:1
• Can occur at any age but peaks in second and third decades

Global Burden:

Route of Infection

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Anatomical Patterns of Involvement

Pathological Changes

History

Presenting Symptoms:

Key History Elements:

• Duration of symptoms (typically weeks to months)
• Constitutional symptoms (weight loss, night sweats, low-grade fever)
• Neurological symptoms (weakness, numbness, bowel/bladder)
• Contact history (TB exposure)
• Country of origin and travel
• Immunocompromise (HIV, diabetes, immunosuppressants)
• Previous TB treatment

Physical Examination

Spinal Assessment:

• Gibbus deformity (angular kyphosis)
• Localized tenderness
• Paraspinal muscle spasm
• Restricted range of motion
• Cold abscess (paravertebral, groin, flank)

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Red Flags

• Rapidly progressive neurological deficit
• Complete paraplegia
• Bladder/bowel dysfunction
• Respiratory compromise (cervical lesions)
• Signs of MDR-TB or treatment failure

Disease-Related Complications

Neurological Complications

Pott's Paraplegia:

• Early onset (active disease): Better prognosis
• Late onset (healed disease): Worse prognosis
• Causes: Abscess, granulation tissue, bony compression

Early-onset (active-disease) paraplegia results from reversible anterior compression by an epidural cold abscess, caseous granulation tissue, or sequestrum/debris, and usually recovers well with decompression and ATT.

Late-onset (healed-disease) paraplegia appears years after the disease has healed and carries a worse prognosis. The cord is compressed by the internal salient (internal gibbus) — the bony ridge of the healed kyphus projecting into the canal at the apex — and by dural/peridural fibrosis, with the cord stretched and draped over the bony ridge; rarely it is due to reactivation or, late, cord atrophy/syringomyelia. Treatment is anterior decompression that removes the internal salient (an anterior problem needs an anterior solution).

Prognosis Factors:

• Duration of deficit (shorter = better)
• Completeness (incomplete = better)
• Age (younger = better)
• Vertebral destruction extent

Treatment-Related Complications

Long-Term Sequelae

• Residual kyphosis
• Chronic pain
• Residual neurological deficit
• Adjacent segment disease
• Growth disturbance (paediatric)

Neurological Recovery

Prognosis by Presentation:

Favourable Factors:

• Short duration of deficit
• Incomplete paraplegia
• Younger age
• Compression by soft tissue (not bone)
• Early treatment initiation

Treatment Outcomes

Long-Term Prognosis

Global Epidemiology

Tuberculosis remains a leading infectious cause of death worldwide, with around 1.3 million deaths annually. Spinal TB is the most common musculoskeletal manifestation, affecting roughly 1 to 2% of all cases of TB, and skeletal involvement occurs in approximately 10% of those with active disease. Burden is concentrated in South and South-East Asia, Sub-Saharan Africa and the Western Pacific. In low-incidence high-income settings, the overwhelming majority of cases are in people born in high-burden countries, frequently presenting as reactivation of latent infection years after migration. HIV co-infection, which is endemic in parts of Sub-Saharan Africa, adds substantially to both the burden and complexity of management.

Major Guidance Side-by-Side

The most important guideline divergence to recognise is duration: WHO endorses a 6-month regimen for drug-susceptible disease (supported by the MRC ambulant-chemotherapy RCT), whereas neurological/CNS-focused guidance such as the British Infection Society recommends a longer 12-month course (2 months of four drugs then at least 10 months of isoniazid and rifampicin) for spinal and CNS disease. Many spinal units extend treatment to 9-12 months in extensive or slow-responding disease.

Diagnostic Standards

A tissue diagnosis (culture, histology and nucleic-acid amplification) is the worldwide gold standard before committing a patient to prolonged therapy, and is especially important in low-prevalence settings and to detect drug resistance. Xpert MTB/RIF on bone or abscess material gives rapid results and simultaneously reports rifampicin resistance, but its sensitivity on bone is only moderate when used alone, so it should be paired with histopathology and culture rather than replacing them.

Practice Variation by Resource Setting

In resource-limited high-burden regions, empirical antitubercular therapy on clinical and radiographic grounds is common where biopsy is impractical, and a conservative "middle-path" approach (chemotherapy with selective surgery) predominates. In low-incidence settings, mandatory public-health notification, contact tracing, directly observed therapy for adherence, and multidisciplinary input from infectious diseases, spinal surgery, radiology and rehabilitation are standard.