Micrograph of diffuse alveolar damage, the histologic correlate of<unk> . H&E stain.<unk>  is a form of fluid accumulation in the lungs not explained by heart failure (noncardiogenic pulmonary edema). It is typically provoked by an<unk>  injury to the lungs that results in flooding of the lungs' microscopic air sacs responsible for the exchange of gases such as oxygen and carbon dioxide with capillaries in the lungs. Additional common findings in<unk>  include partial collapse of the lungs (atelectasis) and low levels of oxygen in the blood (hypoxemia). The clinical<unk>  is associated with pathological findings including pneumonia, eosinophilic pneumonia, cryptogenic organizing pneumonia,<unk>  fibrinous organizing pneumonia, and diffuse alveolar damage (DAD). Of these, the pathology most commonly associated with<unk>  is DAD, which is characterized by a diffuse inflammation of lung tissue. The triggering insult to the tissue usually results in an initial release of chemical signals and other inflammatory mediators secreted by local epithelial and endothelial cells. Neutrophils and some T-lymphocytes quickly migrate into the inflamed lung tissue and contribute in the amplification of the phenomenon. The typical histological presentation involves diffuse alveolar damage and hyaline membrane formation in alveolar walls. Although the triggering mechanisms are not completely understood, recent research has examined the role of inflammation and mechanical stress.
Acute respiratory distress syndrome
Heart failure
Respiratory bronchiolitis
Bacterial pneumonia
Aspiration pneumonia
Community-acquired pneumonia
Hospital-acquired pneumonia
Viral pneumonia