Tuberculosis Study Guide - M.M. Savula 2002

Disseminated pulmonary tuberculosis

Disseminated Pulmonary Tuberculosis develops As a result of the spread of mycobacteria through the bloodstream and Lymph, and is characterized by bilateral, symmetrical lesions in both Lungs. Tuberculous foci may also form in other Organs (bones, Kidneys, serous membranes, Liver, etc.), where mycobacteria are carried by Blood or lymph.

Pathogenesis. Disseminated tuberculosis can be a complication of primary forms of tuberculosis (most commonly in children and adolescents), when MBT from the affected hilar Lymph Nodes enter the jugular vein, SUPERIOR VENA CAVA, and the right side of The Heart, and from there, the pulmonary artery and its branches. This results in bilateral, symmetrical seeding of the lungs with lesions, ranging from solitary foci to total involvement.

In adults, disseminated tuberculosis is more commonly the result of infection reactivation within long-standing, seemingly healed lesions in the intrathoracic lymph nodes, with subsequent lymphohematogenous spread of the infection.

Various extrapulmonary tuberculous lesions can also serve as a source of hematogenous dissemination.

Depending on the severity of bacteremia and host resistance, acute, subacute, or chronic courses of disseminated tuberculosis develop.