Musculoskeletal Tuberculosis William Kwan UNC Internal Medicine-Pediatrics

Pott’s Disease  In endemic countries, usually affects children and young adults  In developed countries, often disease of older adults  20% of tuberculous infections are extrapulmonary  1-5% of tuberculous infections involve the musculoskeletal system  Involves thoracic spine in 50%  Paraspinal abscesses develop in about half of all cases  Pus can remain confined by ligaments and dissect along tissue planes up to supraclavicular space and even down to posterior iliac crest, groin, popliteal fossa

Pott’s Disease  Should be suspected in patients with a history of treated/untreated TB and new back pain  May present with back pain solely without evidence of other tuberculous foci or systemic signs  If sinus formation, stains and cultures of pus positive for mycobacterium only half of the time AND secondary infections by other bacteria may also occur  Variable ESR

Pott’s Disease  X-rays may show irregular cavities and bony destruction without surrounding sclerosis  Usually involves anterior end plates, resulting in herniation of intervertebral disks and “step-off” kyphosis  MRI may show paravertebral abscesses without bony involvement  CT best for looking for bony destruction  MRI best for looking for myelopathy or nerve compression

Extra-axial Tuberculosis  Tuberculous arthritis and bursitis known to occur  Usually involves a single site, but multiple site involvement possible  Progressive pain and swelling without systemic symptoms  Phemister’s Triad:  Juxta-articular osteoporosis  Peripheral osseous erosions  Joint space narrowing  **Must biopsy and culture synovium and periarticular bone as culture of synovial fluid is often nondiagnostic

Treatment  6 to 9 months of INH and rifampin  12 to 18 month regimens were suggested in the past  1st 2 months should include ethambutol and pyrazinamide  Surgery may be indicated if no response to therapy, instability of spine, or neurologic deficits