Extrapulmonary tuberculosis

What it is

Tuberculosis describes a broad range of clinical illnesses caused by Mycobacterium tuberculosis. It can affect virtually every organ, most importantly the lungs, and is typically associated with granuloma formation. Extrapulmonary disease is the part of that range outside the lungs.

How it presents

The main sites, and what each looks like:

• Central nervous system: meningitis and focal tuberculomas.
• Lymphatics: lymphadenitis, cervical, thoracic or abdominal, scrofula when it is of the neck.
• Bone and joint: vertebral disease of the thoracic and lumbar spine with anterior wedging, with or without a psoas abscess, known as Pott's disease. TB belongs in the differential of chronic osteomyelitis and arthritis.
• Pleura: tuberculosis pleurisy.
• Abdominal and pelvic disease.
• Genitourinary: sterile pyuria, which calls for multiple cultures, and it can be associated with infertility.
• GI: it can mimic inflammatory bowel disease, so obtain cultures and histopathology.

How often each site appears can be read from Canadian numbers for 2010: of 1,577 cases, 1,088 (70.0%) were respiratory and 389 (24.7%) nonrespiratory, with 100 (6.3%) both. Among the nonrespiratory sites, peripheral lymph nodes led with 196 (12.4%), then abdominal and bones and joints at 39 (2.5%) each, genitourinary 24 (1.5%), meninges and central nervous system 22 (1.4%), and miliary or disseminated disease 16 (1.0%).