Chronic eosinophilic pneumonia gives peripheral, upper-zone consolidation (the photographic negative of pulmonary oedema); acute eosinophilic pneumonia mimics ARDS with septal thickening and effusions — both confirmed by eosinophils in BAL or blood.
Orient first
- Chronic: peripheral upper-zone consolidation that may migrate; responds dramatically to steroids.
- Acute: young adults, often after starting to smoke; bilateral ground glass, septal thickening, effusions.
- Other causes: drugs, parasites (Löffler), ABPA, eosinophilic granulomatosis with polyangiitis.
Acquire the study
- Non-contrast CT chest with thin sections, prone images if dependent change needs separating.
The manoeuvre
- Axial lung window: distribution — peripheral, subpleural, upper zone vs diffuse.
- Pattern: consolidation, ground glass, crazy paving, septal thickening in mm.
- Effusions and nodes (acute form).
- Compare with prior studies: migration of opacities.
- Airways: central bronchiectasis with mucus (ABPA).
What confirms it
- Compatible CT pattern with BAL or blood eosinophilia.
What licenses you to exclude it
- CT cannot exclude it; normal eosinophils in BAL can.
The classic misread
- Calling peripheral consolidation organising pneumonia or pneumonia without asking for eosinophils.
- Calling acute eosinophilic pneumonia ARDS or oedema.