Fig. 2.

Autopsy studies confirmed extensive alveolar hemorrhage (A, thin arrows reveal red blood cells filling alveoli) with minimal inflammatory reaction within the lung parenchyma (A, thick arrows demonstrate relatively unaffected lung parenchyma). Blood extended into the airways (B, higher power view of red blood cells filling alveolar spaces) and lung, forming bilateral central airway clots and markedly consolidated and hemorrhagic lung parenchyma. No endobronchial sources for bleeding and no pulmonary emboli were found. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)