6 Patterns > Acute Lung Injury Pattern > Subpatterns > w/ Hyaline Membranes

Acute Lung Injury w/ Hyaline Membranes

These are the histologic hallmarks of diffuse alveolar damage (DAD). DAD is an acute reaction pattern to an insult. It may be idiopathic (acute respiratory distress syndrome) or secondary to a number of agents. These patients usually present acutely and are often in the ICU requiring ventilator support. Surgical biopsies are done in an attempt to identify a specific cause of the DAD. Unfortunately, a specific etiology for the DAD is only found in about 30-40% of cases.

Click the image your case is most similar to:

Infection

Drug Reaction

Connective Tissue Dissease

Foreign Material (vascular or inhalational)

Idiopathic DAD/ARDS

Sample Signout

If no additional specific histologic features are identified, consider the following approach to signing the case out:

Acute and organizing diffuse alveolar damage with hyaline membranes (see comment).

Comment:  The biopsy shows extensive acute lung injury in the form of hyaline membranes, edema, and areas of organization.  This is a nonspecific pattern seen in a variety of settings including infection, connective tissues disease, adverse drug reaction, and as an idiopathic entity.  Histologic clues to a specific etiology are not identified.  No significant background fibrosis to suggest a chronic interstitial lung disease is appreciated.  Correlation with final culture studies is suggested to completely exclude infection although there is no necrosis, viral cytopathic effect, granulomas, or extensive neutrophils.  Should no definitive etiology be identified, this may represent idiopathic DAD/ARDS.