Diffuse alveolar damage

Micrograph showing hyaline membranes, the key histologic feature of diffuse alveolar damage. H&E stain.

Diffuse alveolar damage is a histological pattern in lung disease. It is seen in acute respiratory distress syndrome (ARDS),^[1] transfusion related acute lung injury (TRALI) and acute interstitial pneumonia (AIP).

Prevalence

It is a common biopsy finding.^[2] Through histology, diffuse alveolar damage goes through several stages:

1. Exudative phase - similar to pulmonary edema. The alveoli become flooded with exudate
2. Hyaline membrane production. Hyaline membranes are fibrous structures laid down in order to stop oxygen being absorbed via the damaged alveoli.
3. Organising phase

Etiology

Diffuse alveolar damage is associated primarily with ARDS and TRALI in adults, and hyaline membrane disease in neonates. It is most commonly associated with infection.^[3]

References

1. Cotran, Ramzi S.; Kumar, Vinay; Fausto, Nelson; Nelso Fausto; Robbins, Stanley L.; Abbas, Abul K. (2005). Robbins and Cotran pathologic basis of disease. St. Louis, Mo: Elsevier Saunders. p. 715. ISBN 0-7216-0187-1.
2. Parambil JG, Myers JL, Ryu JH (August 2006). "Diffuse alveolar damage: uncommon manifestation of pulmonary involvement in patients with connective tissue diseases". Chest. 130 (2): 553–8. doi:10.1378/chest.130.2.553. PMID 16899858.
3. Parambil JG, Myers JL, Aubry MC, Ryu JH (July 2007). "Causes and prognosis of diffuse alveolar damage diagnosed on surgical lung biopsy". Chest. 132 (1): 50–7. doi:10.1378/chest.07-0104. PMID 17475632.

External links

• Gross pathology of DAD - utah.edu.
• Microscopic pathology of DAD - utah.edu.