Pott's disease

(Sir Percivall Pott, 1714 - 1788, British physician), tuberculous spine infection. It is usually secondary to hematogenous spread from a pulmonary source and involves typically both the vertebral body and the adjacent intervertebral disc which justifies the term of tuberculous spondylodiscitis. The disease presents insidiously with vague backpain and not infrequently it presents with spinal cord dysfunction due to epidural spread. The lower half of the spine is more frequently affected.

The infection first appears adjacent to a disc space and spreads to the rest of the vertebral body. Large paraspinal soft tissue masses, often partially calcified, spreading along the muscles are a frequent factor of long-standing disease. Bilateral psoas abscesses are quite characteristic.

On imaging, massive vertebral body destruction and bone replacement may be depiccted on CT along with disc space narrowing. Soft tissue paraspinal masses are well identified and intratissue calcifications may as well be documented. MR (Fig.1) better delineates the associated involvement of the vertebral bodies and of the disc in between. Both bone and disc show prolonged T2 and T2 relaxation times. MR is also superior, in particular if performed after contrast administration, in documenting eventual epidural intraspinal spread of the soft tissue and associated spinal cord or roots compression. Contrast enhancement is seen also in the affected vertebral bodies and in the disc which confirms the diagnosis of discitis and is an important distinguishing feature in the differential diagnosis with vertebral neoplasms. Gibbus deformities are very frequently secondary to spinal Pott's disease.

FS