III. Tubercular Arthritis
Tuberculosis is an infection caused by Mycobacterium tuberculosis. It may infect any organ including the bone and joints, though the most common site is lungs. Bone and joint involvement occurs when the bacteria spread from other infected sites (often in lungs) through blood.
- Chronic alcoholism
- Immuno-suppressed (decreased immunity) patients
- HIV positive patients
- Drug addicts
It usually affects single, large joints. Knee is the most common joint involved in tubercular arthritis. The joint becomes painful, swollen and stiff. Pain usually increases at night. Constitutional symptoms of tuberculosis like night sweats, fever, weight loss may not be present in tubercular arthritis.
The following investigations are advised to support the diagnosis:
- Blood tests: May show increased levels of ESR.
- X-ray There is no specific radiographic sign of tuberculosis, however, the following signs may be helpful such as soft tissue swelling, thinning of bone (osteopenia), decrease in joint space and destruction of the joint cartilage (late finding).
- Biopsy of synovial membrane and synovial fluid examination may show evidence of tubercular infection.
The disease is treated with standard anti-tubercular drugs. In some cases, plaster cast may be needed to protect the joint from further damage while under therapy.