Medically reviewed by Dr. Ganesh Veerabhadraiah, FINR (Switzerland) | Consultant Neurosurgeon & Spine Specialist | Kauvery Hospital, Electronic City & NeuroWellness Clinic, Jayanagar, Bangalore
Spinal tuberculosis also called Pott’s disease or Pott’s spine is the most common form of skeletal tuberculosis, accounting for approximately 50% of all bone and joint TB cases. India carries the world’s largest TB burden, with 2.8 million new cases reported in 2022 (WHO Global TB Report, 2023). In India, spinal TB predominantly affects adults aged 20–40 years, making it the leading cause of acquired spinal deformity in the working-age population.
The three hallmark early symptoms are progressive back pain, unexplained weight loss, and low-grade fever together called the “TB triad.” Diagnosis requires MRI (gold standard), ESR blood test, and ideally tissue biopsy for culture. Treatment is primarily medical: 9–12 months of anti-tuberculosis drugs (DOTS protocol). Surgery is required in approximately 15–20% of cases for spinal cord compression, abscess drainage, or structural instability. Without early treatment, spinal TB causes vertebral collapse (gibbus deformity) and irreversible paralysis.
What Is Spinal Tuberculosis (Pott's Disease)?
Spinal tuberculosis medically termed tuberculous spondylitis or Pott’s disease, after Sir Percivall Pott who described it in 1779 is a bacterial infection of the vertebral column caused by Mycobacterium tuberculosis. It is classified as extrapulmonary tuberculosis (TB occurring outside the lungs) and is the most common site of skeletal TB worldwide.
The infection typically begins when TB bacteria from a primary lung focus (often subclinical or previously undetected) travel through the bloodstream to the highly vascular cancellous bone of the vertebral bodies. Once established, the bacteria cause granulomatous inflammation the same immune response that characterises pulmonary TB that progressively destroys vertebral bone, intervertebral discs, and surrounding ligaments.
Why spinal TB is particularly dangerous:
– Unlike most spinal infections, spinal TB is often diagnosed late median delay of 6–12 months from symptom onset to diagnosis in India (Indian Journal of Orthopaedics, 2019)
– The thoracic spine (T6–T12) is most commonly affected (approximately 50% of cases), followed by the lumbar spine (35%), and cervical spine (15%)
– Vertebral destruction causes progressive collapse leading to the characteristic angular kyphotic deformity called gibbus
– The spinal cord or nerve roots can be compressed by abscess, granulation tissue, or bone fragments — causing neurological deficits or paralysis
India’s spinal TB burden:
India reports the largest number of new TB cases of any country globally 2.8 million in 2022 (WHO, 2023). An estimated 10–15% of all TB cases in India involve extrapulmonary sites, and of these, skeletal TB accounts for approximately 10% placing India’s annual spinal TB case burden in the tens of thousands. Karnataka and Bangalore’s urban population are not exempt spinal TB is encountered regularly in spine clinics, and critically, is one of the most commonly missed diagnoses in patients presenting with “non-specific” back pain.
What Are the Early Warning Symptoms of Spinal Tuberculosis?
Early recognition is the most important factor in preventing neurological complications. The challenge is that early spinal TB symptoms overlap with common mechanical back pain the most frequent reason for delayed diagnosis.
The Three Core Early Symptoms
1. Progressive back pain
The most consistent symptom present in over 90% of cases. Key features that distinguish spinal TB pain from mechanical back pain:
– Gradual onset over weeks to months (not sudden as in disc prolapse)
– Constant, dull aching — does not fully resolve with rest (unlike mechanical pain)
– Location: typically midline, over the affected vertebral level
– Worsened by movement, coughing, and percussion over the spine
– Night pain — pain disturbing sleep is a red flag for any spinal infection or tumour
– No relief from standard analgesics over multiple weeks
2. Constitutional symptoms — fever, night sweats, weight loss
These systemic symptoms reflect the body’s ongoing immune response to TB infection:
– Low-grade fever: typically 37.5–38.5°C, present in approximately 60–70% of cases
– Drenching night sweats — particularly characteristic
– Unintentional weight loss of more than 5% of body weight over 1–2 months
– Persistent fatigue and loss of appetite
These constitutional symptoms alongside spinal pain should always prompt investigation for spinal TB, regardless of whether the patient has a known TB history. Many patients with spinal TB have never been diagnosed with pulmonary TB.
3. Spinal tenderness on palpation
Localised vertebral tenderness on firm percussion over the spinous processes reproducible at the same level on repeated examination is a characteristic and often-overlooked physical sign of spinal infection.
Later Symptoms (Indicating Disease Progression — More Urgent)
Neurological symptoms -compression of the spinal cord or nerve roots:
– Weakness, heaviness, or dragging of one or both legs — may progress to paraplegia
– Numbness or tingling below the level of infection
– Loss of bladder or bowel control (urinary retention or incontinence) — indicates severe cord compression and surgical emergency
– Muscle spasm surrounding the affected level
Spinal deformity:
– Visible or palpable angular kyphosis (gibbus) — the classic “hump” over the thoracic spine
– Forward lean or list to one side
– Height loss from vertebral collapse
Paravertebral or psoas abscess:
– Swelling alongside the spine or in the groin (psoas abscess tracking down the hip flexor)
– A fluctuant, non-tender mass in the inguinal region in lumbar TB cases
– Draining sinus (rare, in neglected cases)
How Is Spinal Tuberculosis Different from Mechanical Back Pain?
This is the most critical clinical distinction and the most commonly missed.
| Feature | Spinal Tuberculosis | Mechanical Back Pain |
|---|---|---|
| Onset | Gradual over weeks to months | Often sudden or after activity |
| Pain character | Constant, dull, does not fully resolve | Variable — eases with rest |
| Night pain | Yes — disturbs sleep | Rarely disturbs sleep |
| Constitutional symptoms | Fever, weight loss, night sweats | None |
| Spinal tenderness | Localised, reproducible, midline | Diffuse, paraspinal muscles |
| Age | Any age, often 20–40 in India | Most common 30–60 |
| Response to analgesics | Poor — pain persists | Often improves |
| MRI findings | Disc destruction, vertebral erosion, abscess | Disc degeneration, normal bone |
| ESR | Markedly elevated (often >60 mm/hr) | Normal or mildly elevated |
| TB history or contact | Often present (but not always) | Not relevant |
Who Is at Risk of Spinal Tuberculosis in India?
High-risk groups:
Urban migrants and dense living conditions — TB transmission is amplified by overcrowding
Immunocompromised individuals — HIV infection increases TB risk 18–20-fold; diabetes mellitus (affecting 77 million Indians) increases TB risk 2–3-fold
Malnutrition — India’s continuing burden of nutritional deficiency impairs cellular immunity critical for TB containment
Prior or active pulmonary TB — even successfully treated pulmonary TB leaves residual immune sensitisation; reactivation can seed the spine years later
Healthcare workers and contacts — high exposure risk
Elderly patients — immune senescence reduces TB containment capacity
Children— particularly vulnerable to haematogenous dissemination from primary TB focus
Who spinal TB does NOT exclusively affect:
Contrary to common misconception, spinal TB is not restricted to rural, poor, or immunocompromised patients. Urban professionals, students, and middle-class patients without identifiable risk factors present regularly with spinal TB in Bangalore clinics — often after a prolonged diagnostic odyssey of “non-specific back pain.”
How Is Spinal Tuberculosis Diagnosed?
Early diagnosis requires a combination of clinical suspicion, imaging, and laboratory confirmation.
### MRI of the spine (gold standard)
MRI is the most sensitive and specific investigation for spinal TB. Characteristic findings:
– **Disc destruction** — early destruction of the intervertebral disc is pathognomonic of infection (unlike tumours, which spare the disc)
– **Vertebral body erosion** — loss of the normal vertebral contour, often affecting two adjacent vertebrae (skip lesions occur but are less common)
– **Paravertebral abscess** — cold abscess alongside the vertebral column, well-defined, with rim enhancement on contrast MRI
– **Epidural extension** — abscess or granulation tissue compressing the spinal cord or cauda equina
– **Spinal cord signal change** — myelopathy from compression or direct infection
**Key MRI finding that distinguishes spinal TB from metastatic disease:** Disc destruction and disc space loss. Metastatic cancer and multiple myeloma typically spare the intervertebral disc while destroying the vertebral body. Spinal TB destroys both.
### Laboratory investigations
– **ESR (Erythrocyte Sedimentation Rate):** Markedly elevated in active spinal TB — typically >60 mm/hr, often >100 mm/hr. Normalises with successful treatment (useful monitoring marker)
– **CRP (C-Reactive Protein):** Elevated; faster response than ESR to treatment
– **Complete blood count:** Lymphocytosis, anaemia of chronic disease
– **IGRA (Interferon-Gamma Release Assay) / Mantoux test:** Confirms TB exposure; positive in most cases but does not confirm active disease
– **GeneXpert MTB/RIF assay:** Rapid molecular test for TB DNA — highly sensitive; also detects rifampicin resistance
### Tissue biopsy (for definitive diagnosis)
CT-guided needle biopsy or surgical biopsy of the affected vertebra or abscess provides:
– Culture and sensitivity of Mycobacterium tuberculosis — essential for confirming drug-sensitive vs drug-resistant TB
– Histopathology — caseous granulomata with Langhans giant cells confirm tuberculosis
Biopsy is essential before starting anti-TB treatment whenever possible — because drug-resistant TB (MDR-TB) requires different drug regimens and India has a significant MDR-TB burden.
### Chest X-ray and CT chest
Identifies any active or old pulmonary TB focus. A normal chest X-ray does not exclude spinal TB — the primary lung focus may have healed or may be too small to see on plain X-ray.
What Is the Treatment for Spinal Tuberculosis?
The cornerstone of spinal TB treatment is a 9–12 month course of anti-tuberculosis drugs under the WHO-recommended DOTS (Directly Observed Treatment, Short-Course) protocol — now revised to the DOTS-Plus protocol for drug-resistant cases.
**Standard first-line drug-sensitive TB regimen (2HRZE/7HR):**
| Phase | Duration | Drugs | Purpose |
|---|---|---|---|
| Intensive phase | First 2 months | Isoniazid (H) + Rifampicin (R) + Pyrazinamide (Z) + Ethambutol (E) | Rapid bacterial kill |
| Continuation phase | 7–10 months | Isoniazid (H) + Rifampicin (R) | Sterilisation and prevention of relapse |