Pulmonary artery medial hypertrophy in cocaine users without foreign particle microembolization.

A reduction in the DCO has been reported among "free-base" cocaine smokers. We reviewed the pulmonary histopathology in 20 deaths due to cocaine intoxication for either parenchymal or vascular abnormalities which might explain this physiologic finding. Pulmonary artery medical hypertrophy in the absence of foreign particle microembolization was present in four of 20 cases (20 percent). Hemosiderin-laden macrophages were found in seven of 20 cases (35 percent). These abnormalities were not seen in a matched control group. We conclude that in the absence of foreign particle microembolization, pulmonary artery medial hypertrophy occurs among cocaine users, although the mechanism of these vascular changes is unknown. In addition, occult alveolar hemorrhage occurs more frequently among cocaine users than is clinically recognized.