Acute eosinophilic pneumonia

Acute eosinophilic pneumonia (AEP) is a type of eosinophilic lung disease. It is diagnosed when the following combination clinical and radiographic findings occur 5,7:

  • febrile illness of less than five days' duration
  • hypoxaemia
  • diffuse alveolar or mixed alveolar-interstitial opacities on chest radiography
  • bronchoalveolar lavage (BAL) fluid consisting of >25% eosinophils
  • absence of parasitic, fungal or other infection
  • prompt and complete response to corticosteroids
  • no relapse after discontinuation of corticosteroids

Pathology

The exact cause is not well known. Peripheral blood eosinophil counts are usually normal, although they can become elevated during the subsequent clinical course. A very high eosinophil count in bronchoalveolar lavage is characteristic of the condition.

Radiographic features

Imaging features should be interpreted in the correct clinical context.

CT 

Described features include 4,6,8:

Zonal distribution
  • central-to-peripheral zonal distribution 6
    • random ~60%
    • peripheral ~30%
    • central ~10%
  • apicobasal overall zonal distribution 6
    • random ~65% 
    • lower lobes ~30% 
    • upper lobe ~15% 
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Article information

rID: 19561
System: Chest
Tag: cases
Synonyms or Alternate Spellings:
  • Acute eosinophilic pneumonia (AEP)

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