Pott disease is tuberculosis of the spine, usually due to haematogenous spread from other sites, often the lungs. The lower thoracic and upper lumbar vertebrae areas of the spine are most often affected.
It causes a kind of tuberculous arthritis of the intervertebral joints. The infection can spread from two adjacent vertebrae into the adjoining intervertebral disc space. If only one vertebra is affected, the disc is normal, but if two are involved, the disc, which is avascular, cannot receive nutrients, and collapses. In a process called caseous necrosis, the disc tissue dies, leading to vertebral narrowing and eventually to vertebral collapse and spinal damage. A dry soft-tissue mass often forms and superinfection is rare.
Spread of infection from the lumbar vertebrae to the psoas muscle, causing abscesses, is not uncommon.
The disease is named after Percivall Pott, the British surgeon who first described it in the late 18th century.