Tuberculous arthritis is a slowly growing form of disease and causes a monoarticular form of arthritis which involves either young or elderly people. It is as a result of reactivation of primary tubercular focus elsewhere in the body.
Commonly the knee, hip, wrist or ankle joint is involved. There is low grade pyrexia with localized pain at the site with involvement of periarticular structures.
Rupture of a tubercular focus often in the epiphyseal region of long bones into the joint space initiates a progressive granulomatous reaction of synovial membrane and surrounding structures. The joints which bear weight are commonly involved. There is pain which becomes worse on movement, resulting in restriction of movement.
Primary tubercular focus is either in the lungs or genitourinary tract and the spread is mainly hematogenous or by lymphatics. Involvement of spine mainly starts in the vertebral bodies and involves the disc secondarily.
Tuberculous pachymeningitis occurs as a result of extension of tuberculous infection from tuberculous osteitis. In a young subject suffering from tuberculosis of spine there is considerable pain and rigidity of spine.
This is accompanied by low grade pyrexia, night sweats, loss of appetite. As the disease progresses destruction of vertebral body takes place along with formation of paraspinal abscesses and deformity. This results in spinal cord compression leading to paraplegia (Pott’s paraplegia).
Diagnosis of Tuberculous arthritis is dependent on number of investigations. X-ray of the involved joint shows periarticular bone distinction with osteoporosis and over lying soft tissue swelling. MRI is the more sensitive test to demonstrate the changes in the joint as well as in spine.
Synovial fluid when present is aspirated and tested for acid fast bacilli which generally are seen only in 20-30% of cases on smear examination. Culture of synovial fluid or synovial biopsy on arthroscopy yield positive result in 90% of cases.
Treatment of tuberculous arthritis is by anti- tubercular drugs in the same dosage as for pulmonary tuberculosis. Most of the anti-tubercular drugs penetrate the soft tissue and response is generally good. Besides this the joint should be given rest along with muscle strengthening exercises. Weight bearing is avoided.
For tuberculosis of spine if there are signs of compression an exploratory operation may be desirable especially if there is no improvement after a patient has been on antitubercular drugs from 3-4 months.