Which radiological sign specifically describes the early stages of spinal tuberculosis before frank disc space loss?

• A Phantom disc sign (apparent absence of the disc due to severe disc destruction)
• B Ivory vertebra (increased density due to blastic response)
• C Vertebra plana (complete collapse of a single vertebral body)
• D Anterior scalloping with paradiscal osteoporosis and loss of vertebral end-plate definition ✓

Explanation

The earliest radiological signs of Pott's disease are juxta-articular (paradiscal) osteoporosis and loss of normal end-plate definition due to sub-chondral granulomatous erosion, before overt disc space narrowing is visible. Anterior vertebral scalloping follows as the infection erodes the anterior vertebral margin. The 'phantom disc' sign is an advanced sign where disc space obliteration is so severe the disc space disappears. Ivory vertebra is a response seen in Hodgkin's lymphoma and Paget's disease. Vertebra plana is characteristic of eosinophilic granuloma/Langerhans cell histiocytosis in children.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

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Written and medically reviewed by the StethoPrep medical team.