Pathophysiology
ARDS is a clinical syndrome associated with a variety of pathological findings. These include pneumonia, eosinophilic pneumonia, cryptogenic organizing pneumonia, acute fibrinous organizing pneumonia, and diffuse alveolar damage (DAD). Of these, the pathology most commonly associated with ARDS is DAD.
DAD is characterized by a diffuse inflammation of lung parenchyma. The triggering insult to the parenchyma usually results in an initial release of cytokines and other inflammatory mediators, secreted by local epithelial and endothelial cells.
Neutrophils and some T-lymphocytes quickly migrate into the inflamed lung parynchema and contribute in the amplification of the phenomenon.
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.
Read more about this topic: Acute Respiratory Distress Syndrome