miliary pulmonary disease

Miliary pulmonary disease occurs when organisms drain through lymphatics into the lymphatic ducts, which empty into the venous return to the right side of the heart and thence into the pulmonary arteries.

Individual lesions are either microscopic or small, visible (2-mm) foci of yellow-white consolidation scattered through the lung parenchyma (the word "miliary" is derived from the resemblance of these foci to millet seeds).

Miliary lesions may expand and coalesce to yield almost total consolidation of large regions or even whole lobes of the lung. With progressive pulmonary tuberculosis, the pleural cavity is invariably involved, and serous pleural effusions, tuberculous empyema, or obliterative fibrous pleuritis may develop.