Tuberculous spondylodiscitis, also known as Pott's disease, is a chronic granulomatous infection of the vertebral column caused by Mycobacterium tuberculosis. It is the most common form of musculoskeletal tuberculosis and accounts for approximately 50% of skeletal TB cases. The disease usually develops following hematogenous spread from a primary pulmonary or extrapulmonary focus and predominantly involves the thoracic and lumbar spine.

Delayed diagnosis may lead to vertebral destruction, spinal deformity, epidural abscess formation, spinal instability, and irreversible neurological deficits including paraplegia. Early recognition and prompt initiation of anti-tuberculosis therapy are essential to prevent permanent disability.

Epidemiology

• Most common form of skeletal tuberculosis

• Represents approximately 1–2% of all tuberculosis cases

• More common in regions with high TB prevalence

• Frequently affects young adults but may occur at any age

• Higher risk among:

  • HIV-infected patients

  • Diabetes mellitus

  • Chronic kidney disease

  • Malnutrition

  • Immunosuppressive therapy

  • Elderly individuals

Etiology

The causative organism is:

• Mycobacterium tuberculosis complex

Rarely:

• Mycobacterium bovis

• Non-tuberculous mycobacteria (immunocompromised patients)

Pathophysiology

Tuberculous spondylodiscitis develops when Mycobacterium tuberculosis spreads hematogenously from a primary focus, most commonly the lungs, through the arterial circulation or Batson's valveless vertebral venous plexus. The infection usually begins in the anterior portion of the vertebral body adjacent to the end plate. Unlike pyogenic infections, tuberculosis produces a chronic granulomatous inflammatory response characterized by caseating necrosis rather than acute suppuration.

Progressive destruction of adjacent vertebral bodies results in collapse of the intervertebral disc, kyphotic deformity, and vertebral instability. Infection frequently extends beneath the anterior longitudinal ligament, involving multiple vertebral levels. Cold abscesses may develop in the paravertebral, psoas, or epidural spaces because of the relatively limited acute inflammatory response. Progressive compression of the spinal cord or nerve roots may lead to radiculopathy, myelopathy, or paraplegia if treatment is delayed.

Risk factors

• Previous tuberculosis infection

• HIV infection

• Diabetes mellitus

• Malnutrition

• Chronic renal failure

• Immunosuppressive therapy

• Organ transplantation

• Advanced age

• Alcohol misuse

• Close contact with tuberculosis patients

Clinical presentation

Symptoms usually develop gradually over weeks to months.

Constitutional symptoms

• Fever

• Night sweats

• Weight loss

• Fatigue

• Loss of appetite

Local spinal symptoms

• Persistent back pain

• Local spinal tenderness

• Muscle spasms

• Reduced spinal mobility

• Progressive kyphotic deformity

Neurological manifestations

• Extremity weakness

• Numbness

• Paresthesia

• Radicular pain

• Gait disturbance

• Bladder or bowel dysfunction in advanced disease

Complications during presentation

• Paravertebral abscess

• Psoas abscess

• Gibbus deformity

• Spinal instability

• Paraplegia

Diagnostic criteria

Diagnosis is established by combining clinical findings, imaging, microbiological confirmation, and histopathology.

Diagnosis is highly likely when there is:

• Chronic back pain lasting more than 4 weeks

• Constitutional symptoms suggestive of tuberculosis

• MRI findings compatible with tuberculous spondylodiscitis

• Microbiological confirmation of M. tuberculosis from biopsy, aspirate, or culture

Histopathology showing caseating granulomatous inflammation strongly supports the diagnosis.

Investigations

Laboratory investigations

• Complete blood count (CBC)

• Erythrocyte sedimentation rate (ESR)

• C-reactive protein (CRP)

• HIV serology

• Blood cultures (to exclude pyogenic infection)

• Tuberculin skin test or interferon-gamma release assay (supportive)

• Sputum examination if pulmonary TB is suspected

Microbiological investigations

• CT-guided vertebral biopsy for acid-fast bacilli (AFB)

• Mycobacterial culture

• GeneXpert MTB/RIF assay

• Histopathological examination of biopsy tissue

Imaging

Plain spinal radiographs

May demonstrate:

• Disc space narrowing

• Vertebral body destruction

• End-plate erosion

• Kyphotic deformity

• Paravertebral soft tissue shadows

MRI with contrast (investigation of choice)

Shows:

• Early marrow oedema

• Disc involvement

• Epidural abscess

• Paravertebral abscess

• Neural compression

• Skip lesions

CT scan

Useful for:

• Cortical bone destruction

• Surgical planning

• Image-guided biopsy

Differential diagnosis

• Pyogenic spondylodiscitis

• Vertebral osteomyelitis

• Metastatic spinal disease

• Multiple myeloma

• Degenerative disc disease

• Ankylosing spondylitis

• Epidural abscess

Treatment

Management requires prolonged anti-tuberculosis therapy together with supportive care and surgery when indicated.

Non-pharmacological treatment

• Bed rest during acute pain

• External spinal immobilization using spinal orthoses

• Nutritional support

• Physiotherapy after acute symptoms improve

• Rehabilitation for neurological deficits

• Regular neurological assessment

Pharmacological treatment

Anti-tuberculosis therapy

Treat according to the current National Tuberculosis and Leprosy Programme (NTLP) guidelines.

Standard drug-susceptible tuberculosis regimen:

Intensive phase (2 months)

• Rifampicin

• Isoniazid

• Pyrazinamide

• Ethambutol

Continuation phase (4–10 months)

• Rifampicin

• Isoniazid

The total duration is generally 6–12 months, depending on national guidelines, disease severity, neurological involvement, and clinical response.

Pain management

Ibuprofen

• 400 mg orally stat, then 200 mg every 8 hours

OR

Diclofenac sodium

• 50 mg orally every 8 hours

OR

Meloxicam

• 7.5–15 mg orally every 12–24 hours

Severe pain

Diclofenac

• 75 mg intramuscularly every 12 hours by deep IM injection

OR

Tramadol

• 100 mg intramuscularly every 12 hours for 1–3 days

THEN

Tramadol

• 50 mg orally every 8 hours for up to 14 days

Topical analgesics

Diclofenac gel

• Apply every 12 hours

OR

Ketoprofen gel

• Apply every 12 hours

Gastroprotection

For patients receiving prolonged NSAIDs or with increased gastrointestinal risk:

Omeprazole

• 20 mg orally once daily for 2–4 weeks

OR

Pantoprazole

• 40 mg orally once daily for 2–4 weeks

OR

Esomeprazole

• 40 mg orally once daily for 2–4 weeks

OR

Lansoprazole

• 30 mg orally once daily for 2–4 weeks

Radicular symptoms

Pregabalin

• 75–150 mg orally once daily for 4 weeks (dose may be escalated according to response)

AND

Vitamin B1 + Vitamin B6 + Vitamin B12

• One tablet orally once daily for 4 weeks

AND

Baclofen

• 10–20 mg orally every 8 hours for up to 2 weeks

OR

Tizanidine

• 2–4 mg orally every 8 hours for up to 2 weeks

Surgical management

Surgery is indicated when conservative treatment fails or when complications develop.

Indications

• Failure to respond to pharmacological therapy

• Progressive neurological deficits

• Significant spinal cord compression

• Large paravertebral or epidural abscess

• Progressive spinal deformity

• Mechanical spinal instability

• Diagnostic uncertainty requiring biopsy

• Severe kyphosis causing functional impairment

Surgical procedures

• Surgical decompression

• Debridement of infected vertebral bodies and discs

• Drainage of paravertebral or epidural abscesses

• Autologous bone grafting

• Instrumented spinal stabilization when indicated

• Minimally invasive or open approaches depending on disease extent and available expertise

Complications

• Kyphotic deformity (gibbus)

• Chronic pain

• Spinal instability

• Epidural abscess

• Psoas abscess

• Neurological deficits

• Paraplegia

• Bladder and bowel dysfunction

• Recurrence

• Death (untreated disease)

Rehabilitation

• Progressive physiotherapy

• Muscle strengthening

• Gait training

• Occupational therapy

• Assistive devices when needed

• Long-term follow-up of neurological recovery

Prognosis

The prognosis is favourable when diagnosis is made early and appropriate anti-tuberculosis therapy is started promptly. Most patients achieve infection control and neurological recovery with combined medical treatment, although advanced disease with severe vertebral destruction or delayed presentation may result in permanent deformity or neurological disability.

Prevention

• Early diagnosis and treatment of pulmonary tuberculosis

• HIV testing and treatment where appropriate

• Prompt investigation of persistent back pain in endemic regions

• Nutritional support

• Adherence to anti-tuberculosis therapy

• Contact tracing and tuberculosis control programmes

Patient education

Patients should be advised to:

• Complete the entire anti-tuberculosis treatment course.

• Attend regular follow-up appointments.

• Report worsening weakness, numbness, or bowel/bladder dysfunction immediately.

• Wear spinal braces as instructed.

• Maintain good nutrition.

• Avoid smoking and excessive alcohol intake.

• Participate in rehabilitation once medically stable.