The usual sites to be involved in spinal tuberculosis are the lower thoracic and upper lumbar vertebrae. The source of infection is usually outside the spine. It is most often spread from the lungs via the blood. There is a combination of osteomyelitis and infective arthritis.
Usually more than one vertebra is involved. The area most affected is the anterior part of the vertebral body adjacent to the subchondral plate. Tuberculosis may spread from that area to adjacent intervertebral discs. In adults, disc disease is secondary to the spread of infection from the vertebral body but in children it can be a primary site, as the disc is vascular in children.
- Elevated ESR.
- Strongly positive Mantoux skin test.
- Spinal X-ray may be normal in early disease, as 50% of the bone mass must be lost for changes to be visible on X-ray. Plain X-ray can show vertebral destruction and narrowed disc space.
- MRI scanning may demonstrate the extent of spinal compression and can show changes at an early stage. Bone elements visible within the swelling, or abscesses, are strongly suggestive of spinal tuberculosis rather than malignancy.
- CT scans and nuclear bone scans can also be used but MRI is best to assess risk to the spinal cord.
- A needle biopsy of bone or synovial tissue is usual. If it shows tubercle bacilli this is diagnostic but usually culture is required. Culture should include mycology.
- All patients presenting with extrapulmonary tuberculosis should be offered a chest X-ray and, if possible, culture of a spontaneously-produced respiratory sample to exclude or confirm co-existing pulmonary tuberculosis. Site-specific tests to exclude or confirm additional sites of tuberculosis should also be considered.