Diffuse alveolar damage

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Diffuse alveolar damage, abbreviated DAD, is a relatively common lung pathology that is grouped with the diffuse lung diseases and has several clinical correlates.

Diffuse alveolar damage
Diagnosis in short

Hyaline membranes. H&E stain.
Site lung - see diffuse lung diseases

Prognosis often poor, dependent on severity and comorbidities
Clin. DDx acute respiratory distress syndrome (ARDS), acute interstitial pneumonia (AIP), transfusion related acute lung injury (TRALI)
Treatment dependent on underlying cause

General

Etiology:

  • Abrupt hypoxemia with pulmonary infiltrates leading to epithelial cell and endothelial cell death not accompanied by cardiac failure.[1]

DAD is the histologic correlate of:

  • Acute respiratory distress syndrome (ARDS).
  • Acute interstitial pneumonia (AIP).
  • Transfusion related acute lung injury (TRALI).

The DDx is broad:[2]

  • Infection/sepsis.
  • Toxic (smoke, oxygen).
  • Drug (amiodarone, chemotherapy).
  • Trauma/shock.
  • Inflammatory.
  • Idiopathic.

Microscopic

Features:[3][4]

  1. Exudative:
    • Hyaline membranes - key feature.
      • Debris (pink crap) lines the alveolar spaces.
  2. Proliferative:
    • Interstitial thickening.
    • Inflammation (lymphocytes).
    • Hobnailing of alveolar lining cells (type 2 pneumocyte hyperplasia[5]).
    • Edema (link pink crap in the alveoli).
    • Masson bodies in the airway.
    • Hyaline material (usu. focal) - key feature.
  3. Fibrotic:
    • Interstitial inflammation.
    • Fibrosis.

DDx:[4]

Images

www:

See also

References

  1. Mitchell, Richard; Kumar, Vinay; Fausto, Nelson; Abbas, Abul K.; Aster, Jon (2011). Pocket Companion to Robbins & Cotran Pathologic Basis of Disease (8th ed.). Elsevier Saunders. pp. 364. ISBN 978-1416054542.
  2. Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 91. ISBN 978-0781765275.
  3. Klatt, Edward C. (2006). Robbins and Cotran Atlas of Pathology (1st ed.). Saunders. pp. 103. ISBN 978-1416002741.
  4. 4.0 4.1 Castro, CY. (2006). "ARDS and diffuse alveolar damage: a pathologist's perspective.". Semin Thorac Cardiovasc Surg 18 (1): 13-9. doi:10.1053/j.semtcvs.2006.02.001. PMID 16766248.
  5. URL: http://d3jonline.tripod.com/20-Pulmonary_II/Pathology_of_Interstitial_Lung_Diseases.htm. Accessed on: 22 February 2012.