Spinal tuberculosis (Pott disease) is Mycobacterium tuberculosis infection of vertebrae and surrounding structures. It constitutes 50% of all bone-joint tuberculosis. The thoracolumbar junction (T12-L1) is the most commonly affected region (60-70%) — this region's rich arterial supply from both thoracic and lumbar aortic branches facilitates hematogenous seeding. Differentiation of spinal TB from pyogenic spondylodiscitis has critical clinical importance as treatment strategies are fundamentally different. Distinguishing features of TB: (1) anterior vertebral body destruction — subligamentous spread extending under the anterior longitudinal ligament across multiple vertebrae, (2) relative disc preservation — M.tuberculosis does not produce proteolytic enzymes and disc matrix destruction is much slower compared to pyogenic infection, (3) large paravertebral cold abscess — disproportionately large relative to vertebral destruction, calcified wall, may extend to inguinal region as psoas abscess, (4) skip lesions — non-contiguous vertebral involvement via hematogenous spread, (5) gibbus deformity — angular kyphosis from anterior vertebral collapse. MRI shows rim-enhancing abscess, vertebral body T1 low/T2 high signal, epidural collection, and posterior element involvement (rare but specific to TB).
Age Range
15-50
Peak Age
30
Gender
Male predominant
Prevalence
Uncommon
Spinal TB develops via hematogenous spread from pulmonary or extrapulmonary TB focus. M.tuberculosis reaches the anterior portion of the vertebral body through arterial blood flow or Batson's valveless venous plexus — the anterior vertebral body is the region with richest arterial supply and most favorable for bacterial seeding. Established bacilli trigger granulomatous inflammation: macrophages fuse to form Langhans-type giant cells, epithelioid cells establish granuloma structure, and central caseous necrosis develops. Activated macrophages surrounding caseous necrosis secrete TNF-alpha, metalloproteinases, and reactive oxygen species causing bone matrix destruction. Pathophysiological features distinguishing TB from pyogenic infection: (1) Disc preservation — M.tuberculosis does not produce proteolytic enzymes such as collagenase or hyaluronidase, so annulus fibrosus and nucleus pulposus are not chemically destroyed; in pyogenic bacteria (S.aureus), these enzymes rapidly destroy the disc. Disc involvement in TB occurs only late through mechanical compression or secondary bacterial infection. (2) Subligamentous spread — caseous material spreads longitudinally under the anterior longitudinal ligament across multiple vertebrae; this anterolateral spread pattern leads to large paravertebral cold abscess formation. (3) Cold abscess — TB's chronic granulomatous response is 'cold' unlike acute neutrophilic response (minimal fever/redness/warmth), caseous material is enclosed by thick granulomatous wall and calcification may develop. (4) Skip lesions — multifocal hematogenous spread allows non-contiguous vertebral involvement; retrograde flow in Batson plexus facilitates this spread. (5) Posterior element involvement — TB may rarely involve pedicles and lamina; this is very rare in pyogenic infection and specific to TB. Gibbus deformity is angular kyphosis from anterior vertebral body collapse — wedge-shaped anterior compression disrupts spinal mechanics.
Anterior vertebral body destruction with relative disc preservation — disc matrix destruction is very slow as M.tuberculosis does not produce proteolytic enzymes. Most critical distinguishing finding from pyogenic infection.
On contrast-enhanced sequences, paravertebral cold abscess shows rim enhancement — thick granulomatous capsule enhances intensely, central caseous content does not. Abscess is disproportionately large relative to vertebral destruction. Bilateral psoas abscess is pathognomonic.
Report Sentence
Bilateral paravertebral rim-enhancing collection at the thoracolumbar junction (cold abscess), disproportionately large relative to vertebral destruction with calcified wall, suggestive of tuberculous spondylitis.
T1 signal loss in the anterior portion of vertebral body — normal fatty marrow replaced by inflammatory edema. Critically, disc T1 signal intensity is preserved or minimally changed — in pyogenic infection, disc is involved early.
Report Sentence
T1 signal loss in the anterior portions of ...-... vertebral bodies with relative preservation of disc signal intensity; consistent with spinal tuberculosis.
CT shows anterior vertebral body destruction, subligamentous collection (calcified wall), relatively preserved disc space, and bone fragments/sequestrations. Calcification of abscess wall is a finding specific to TB.
Report Sentence
Anterior destruction of ...-... vertebral bodies, large paravertebral collection with calcified wall, and relatively preserved disc space, consistent with spinal tuberculosis.
T2/STIR shows heterogeneous hyperintense signal in vertebral body (edema + caseous necrosis), heterogeneous hyperintense signal in central area of paravertebral abscess (caseous material), and thick hypointense capsule. Skip lesions are best visualized on T2/STIR.
Report Sentence
Heterogeneous hyperintense signal in ...-... vertebral bodies on T2/STIR with thick hypointense capsule paravertebral collection.
Sagittal MR shows non-contiguous vertebral involvement (skip lesions) and subligamentous collection extension under the anterior longitudinal ligament. Whole spine MRI screening is recommended to detect skip lesions.
Report Sentence
Signal changes are also observed in ... vertebra in addition to primary involvement at ...-... (skip lesion) with accompanying anterior subligamentous collection extension; consistent with tuberculous spondylitis.
Criteria
Most common form. Starts adjacent to end-plate. Anterior vertebral destruction + cold abscess.
Distinct Features
Destruction starting adjacent to disc, common in adults, thoracolumbar junction predilection
Criteria
Extension under anterior longitudinal ligament. Multiple vertebral involvement. Very large paravertebral abscess.
Distinct Features
Scalloping (anterior vertebral erosion), longitudinal collection, prominent disc preservation
Criteria
Starts in center of vertebral body. Disc preserved. More common in children (disc avascular).
Distinct Features
Isolated destruction in vertebral body, minimal disc involvement, vertebra plana may develop
Criteria
Posterior element involvement (pedicles, lamina, spinous process). Rare (2-10%). Specific to TB.
Distinct Features
Very rare in pyogenic infection — posterior element involvement strongly suggests TB
Distinguishing Feature
Pyogenic spondylodiscitis involves disc early with enhancement, small collection, skip lesions rare; TB preserves disc, large cold abscess, subligamentous spread, skip lesions
Distinguishing Feature
Isolated epidural abscess shows no vertebra/disc destruction; spinal TB has dominant vertebral destruction and large cold abscess
Distinguishing Feature
Vertebral hemangioma T1 bright (fat), polka-dot, no destruction, no abscess; spinal TB T1 low, anterior destruction, large abscess
Urgency
urgentManagement
medicalBiopsy
NeededFollow-up
3-monthSpinal TB treatment begins with anti-tuberculosis chemotherapy (6-12 months RHZE: rifampicin+isoniazid+pyrazinamide+ethambutol). Surgery (decompression+stabilization+drainage) is required for neurological deficit, instability, large abscess, or treatment failure. CT-guided abscess aspiration is performed for diagnostic confirmation and culture. Early diagnosis and treatment determine neurological outcomes. Corrective surgery may be performed for gibbus deformity. High clinical suspicion is important in endemic regions and HIV-positive patients.
Spinal tuberculosis treatment begins with anti-tuberculosis chemotherapy (6-12 months: rifampicin + isoniazid + pyrazinamide + ethambutol). Surgical intervention (decompression + stabilization + drainage) is required for neurological deficit, instability, large abscess, or treatment failure. Early diagnosis and treatment determine neurological outcomes. Corrective surgery may be performed for gibbus deformity. High clinical suspicion is important in endemic regions (South Asia, sub-Saharan Africa) and immunosuppressed patients (HIV).