Pott disease, or Pott's disease, is a form of tuberculosis that occurs outside the lungs whereby disease is seen in the vertebrae. Tuberculosis can affect several tissues outside the lungs including the spine, a kind of tuberculous arthritis of the intervertebral joints. The disease is named after Percivall Pott (1714–1788), a British surgeon. The lower thoracic and upper lumbar vertebrae are the areas of the spine most often affected. The formal name for the disease is tuberculous spondylitis.
Pott’s disease results from haematogenous spread of tuberculosis from other sites, often the lungs. The infection then spreads 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.