Acute Eosinophilic Pneumonia

Epidemiology


Physiology

  • Unclear mechanism (possible hypersensitivity phenomenon)

Pathology

  • Pathologic patterns: similar to Chronic Eosinophilic Pneumonia, [[Chronic Eosinophilic Pneumonia]]
  • See also [Chest 1979: 76: 33-36/ JAMA 1983: 250: 2602]

Diagnosis

Pleural Fluid

  • Eosinophilia with high pH

Sputum

  • Eosinophilia

ABG

  • Hypoxemia

PFT’s

  • Obstructive Defect/Hyperinflation: may be seen

FOB

  • BAL: eosinophilia >40% (normal <2%) is highly suggestive of eosinophilic pneumonia (BAL eosinophilia is nearly always seen, even when peripheral eosinophilia is absent)
  • TBB: may be diagnostic

CXR/Chest CT Patterns

  • Alveolar Infiltrates: may present as “reverse pulmonary edema” (upper lobe-predominant peripheral infiltrates) pattern (pattern also seen in BOOP)
    • Infiltrates may be fleeting/may not conform to lobar or segmental boundaries
    • Hilar adenopathy/small effusions: may be seen
  • Interstitial Infiltrates: may be superimposed on alveolar infiltrates later in course

Serum IgE

  • Normal-mildly elevated

Circulating Immune Complexes

  • Positive

CBC

  • Eosinophilia: may be absent in some cases
  • Leukocyctosis:

ESR

  • Elevated (often >100)

Clinical

(symptoms may progress over days-weeks)

  • Wheezing: reported in some cases (generally recent onset)
  • Cough: dry or mucoid sputum
  • Dyspnea:
  • Weight loss:
  • Night sweats:
  • Hemoptysis: occasional
  • Fever:
  • Lymphadenopathy:
  • Hepatomegaly:
  • Pleural Effusion (see [[Pleural Effusion-Exudate]])

Treatment

  • Steroids: results in rapid resolution
    • Taper over 10 days-12 weeks (differs from Chronic Eos Pneumonia in that it does not recur after steroid withdrawal)

References

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