Non-pulmonary TB

In a general sense, non-pulmonary tuberculosis describes a TB infection which has disseminated, or spread, to various sites in the body from the lungs (the most common site of infection). Although primarily thought of as a disease of the lungs, TB may cause serious health risks if access is gained to other parts of the body.

Here are some general facts about non-pulmonary tuberculosis which may prove useful in gaining an understanding of the pathogen (disease causing organism) and its effects:

• The tubercle bacilli usually disseminate through out the body during the early stages of infection. From here (usually the blood stream) they can infect various sites.
• Although no organ /site in the body is immune to the TB bacillus, certain areas are of special concern due to their vulnerability and vital functions.
• Pleural and lymphatic TB are the most common types of non-pulmonary TB. (Note: the term pleural refers to the membranes which line various areas/organs, mainly in or near the thoracic cavity.)
• Non-pulmonary TB is very common among patients with an HIV infection in conjunction with pulmonary TB. 60-80% of these patients develop non-pulmonary TB in contrast to 17% of non-HIV patients who develop non-pulmonary TB. Extra-pulmonary TB is considered an AIDS defining disease.
• Non-pulmonary TB is also common in children with an initial pulmonary TB infection. 30% of these children develop non-pulmonary TB.
• Diagnosis of non-pulmonary TB is usually problematic due to the inaccessibility of the sites of infection and the relatively small number of bacilli.