Diffuse Alveolar Damage (DAD) is a pathological pattern of lung
injury characterized by widespread damage to the alveolar
structures, often seen as the hallmark of acute respiratory distress
syndrome (ARDS). It can result from various causes, including
infections, sepsis, trauma, or inhalation of toxic substances. The
pathogenesis involves an initial injury to the alveolar-capillary
barrier, leading to fluid leakage into the alveolar spaces,
inflammation, and subsequent formation of hyaline membranes
within the alveoli. Over time, this causes fibrosis and thickening of
the alveolar walls, severely impairing gas exchange. Clinically, DAD
presents with symptoms such as acute shortness of breath, low
oxygen levels, and respiratory failure. Diagnosis is based on clinical
findings and imaging, where chest X-rays or CT scans reveal
widespread ground-glass opacities and consolidations.
Pathological confirmation via lung biopsy shows the characteristic
hyaline membranes and alveolar collapse. (Etesami)