What are the clinical signs of spinal cord compression in Pott disease (tuberculous spondylitis)?

Clinical Signs of Spinal Cord Compression in Pott Disease

Spinal cord compression in Pott disease (tuberculous spondylitis) presents with a characteristic triad: progressive back pain (present in 69-88% of cases), lower limb weakness (69%), and gibbus deformity (46%), often accompanied by constitutional symptoms including fever, weight loss, and malaise. 1, 2

Primary Neurological Manifestations

Motor Deficits

• Progressive lower limb weakness is the most common neurological presentation, occurring in approximately 69% of patients with Pott disease 1
• Motor deficits range from mild paraparesis (ambulatory with assistance) to complete paraplegia with no muscle movement 3, 4
• Weakness typically develops gradually over weeks to months, though acute onset can occur in 4 cases per 21 surgical patients 4

Sensory Changes

• Sensory deficits and numbness in the lower limbs develop as cord compression progresses 3
• Radicular pain patterns may occur, particularly when nerve roots are involved (seen in 4 of 21 surgical cases) 4

Reflex Abnormalities

• Hyperreflexia is detectable in approximately 36% of patients (18 of 50 cases) at presentation, indicating upper motor neuron involvement 5
• Absent lower limb reflexes may occur with severe compression or cauda equina involvement 3

Sphincter Dysfunction

• Bladder and bowel dysfunction develops with progressive cord compression, manifesting as urinary retention, incontinence, or constipation 3
• Perianal or saddle numbness indicates cauda equina involvement when disease affects lower lumbar levels 3

Constitutional and Spinal Symptoms

Systemic Features

• Low-grade fever, weight loss, fatigue, and malaise are common constitutional symptoms that accompany the neurological deficits 2
• Night sweats and anorexia may be present as part of systemic tuberculosis 2

Spinal Deformity

• Gibbus deformity (angular kyphosis) is visible in 46% of patients and results from vertebral body collapse 1
• Palpable mass may be detected in 10% of cases, representing paraspinal or epidural abscess formation 1
• Localized tenderness over the affected spinous processes is an invaluable clinical finding on routine examination 2

Clinical Presentation Patterns by Severity

Early/Mild Compression

• Twenty-two of 50 patients (44%) may have normal neurology at initial presentation despite radiological evidence of cord compression on MRI 5
• Persistent nighttime back pain with reduced range of motion may be the only early signs 6

Moderate Compression

• Motor deficits with preserved ambulation (Frankel grade C or better) represent the most common presentation requiring intervention 5
• Hyperreflexia without overt weakness indicates evolving myelopathy 5

Severe Compression

• Complete paraplegia with acute onset represents the most severe presentation and requires emergency surgical decompression 4, 1
• Progressive neurological deficit despite medical treatment occurs in approximately 6% of cases (3 of 50 patients) 5

Anatomical Location and Clinical Correlation

• The thoracic spine is the most commonly affected site in Pott disease, which explains the predominance of lower limb symptoms 1, 2
• Thoracolumbar involvement may produce mixed upper and lower motor neuron signs 4
• Cervical involvement is less common but produces upper limb symptoms when present 3

Critical Diagnostic Indicators

Laboratory Markers

• Elevated erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) support the diagnosis 3
• Leukocytosis may be present but is not universal 6

Imaging Correlation

• MRI demonstrates soft tissue effacement of the cord with complete obliteration of the thecal sac at the compression level, which correlates with clinical severity 5
• Chronic infections like tuberculosis can have similar MRI appearance to metabolic myelopathies, requiring tissue diagnosis 3

Important Clinical Pitfalls

• Diagnostic delay is common due to indolent presentation with nonspecific symptoms, averaging 23-26 days from symptom onset 3, 6
• Normal neurology does not exclude significant radiological cord compression—44% of patients with MRI-documented compression may have no clinical deficits initially 5
• The severity of neurological deficit at presentation inversely correlates with potential for functional recovery, making early recognition critical 6
• Symptoms may be mistaken for degenerative disc disease, delaying appropriate anti-tuberculous treatment 3