•  The blue arrows point to the type II pneumocytes which are very prominent; their nuclei protruding into the alveolar space.

•  The arrows highlight the thickened septum.

•  The septum contains excess collagen, fibroblasts, and lymphocytes.

•  Hyaline membranes are not present.

• Result of diffuse capillary damage in the lung with capillary leak

• Endothelial cell damage (direct, secondary to inflammatory cells and mediators esp neutrophils, due to endotoxin)

• Capillary leak into the alveolae with accumulation of edema and proteinaceous, necrotic material that forms hyaline membranes

• Edema interferes with gas exchange

• Direct toxicity due to smoke inhalation, drugs etc.

• Secondary effect of profound hypoxia and circulatory failure

• Sequel to severe trauma or other life threatening condition

• Rapid development of profound respiratory failure

• Fatality rate is high.

• Heavy lungs which are deep reddish purple and stiff

• Congestion of the vessels and proteinaceous acellular edema in the alveolae

• Accumulation of vividly eosinophilic, acellular hyaline membranes against alveolar septae

• Organize into circular fibrous swirls which over time replace alveoli

• Occasionally resolve completely

• Cotran RS, Kumar V, Robbins SL: Robbins Pathologic Basis of Disease. 5th edition. Philadelphia, W.B. Saunders, 1994, pp. 676-678.

• Current literature from PubMed at National Library of Medicine