Acute Lung Injury

Acute lung injury (ALI) is acute pulmonary inflammation with underlying pathology of disruption of the pulmonary vasculature endothelial and alveolar epithelial barriers. ALI is not an uncommon diagnosis and has a myriad of causes including pulmonary infection, (including sepsis), drugs, connective tissue disease, and polytrauma. Patients present clinically with hypoxemia with imaging supportive of bilateral pulmonary findings without pulmonary edema. The imaging findings in ALI mirror pathologic changes, with a transition from an early ("exudative") phase to a later fibroblast-rich ("organizing" or "proliferative") phase to, in some cases, a fibrotic phase. The diagnosis of ALI is separate from, but can clinically overlap in presentation with, acute respiratory distress syndrome and is characterized by diffuse alveolar damage and organizing pneumonia patterns on pathology. Clinical management is most often supportive and can include corticosteroids, mechanical ventilation, and careful fluid management, with the goal of preserving and recovering lung function.