25th February 2025

Mycobacterium

Overview of mycobacterial joint infection

Mycobacterium tuberculosis can invade the synovium and disc space, with tissue destruction. In developed countries, this occurs in <5% of TB cases. Risk factors include pre-existing joint disease and immunosuppression. Atypical mycobacteria are rarer causes.

Signs and symptoms of mycobacterial joint infection

Infection is usually low-grade and slowly progressive, without warmth or erythema. It is usually monoarticular, affecting the spine in 50% (Pott’s disease) and then the hip, knee, ankle and sacroiliac joint. Spinal cord compression is a serious complication.

Investigations in mycobacterial joint infection

Synovial fluid analysis is usually sterile, and tissue biopsy may be needed. Biopsy shows caseating granulomas.

Management of mycobacterial joint infection

Treatment is with the local anti-TB regimen for 9 months, with initial joint rest and acute spine immobilisation.