Acute Lung Injury

Acute lung injury typically refers to lung disease occurring within a short time period of a pulmonary insult, and often results in acute respiratory distress syndrome (ARDS) clinically. Diffuse alveolar damage (DAD) is the most common histologic finding in patients with ARDS. Acute fibrinous and organizing pneumonia (AFOP) and organizing pneumonia (OP) may also occur, although these may present with a subacute onset as well. The aim of this chapter is to review the histologic features of DAD, AFOP, and OP, and present a practical approach to diagnosis. Features discriminating DAD, AFOP, and OP from each other are discussed, as well as other diagnoses that should be considered in the histologic differential diagnosis.