Chronic Eosinophilic Pneumonia

Epidemiology

  • Sex: 2-fold more common in females
  • Age: peak incidence in 30’s (but can occur at any age)
  • More chronic clinical presentation (>14 days of symptoms) than [[Acute Eosinophilic Pneumonia]]
  • Associated With:
    • Asthma/Atopic Diseases: pre-existing atopic disease (especially asthma) is present in 50% of cases
    • IBD: ulcerative colitis

Physiology

  • Unclear

Pathology

Pathologic Patterns

  • Eosinophilic Pneumonia: interstitial and alveolar eosinophil infiltration
    • Macrophages and multinucleated giant cells (giant cells may contain eosinophil fragments and crystals, which may be early Charcot-Leyden crystals)
    • Large Charcot-Leyden crystals and features of BO and vasculitis may also be seen in some cases
  • Usual Interstitial Pneumonia (UIP): may be seen in some cases
  • BOOP/Organizing Pneumonia Features/Cellular Interstitial Pneumonia (CIP): seen in some cases
  • Honeycombing: seen late

Diagnosis

CBC

  • Eosinophilia (absent in about 15% of cases): mean peripheral eosinophil count is around 26%
  • Neutrophilia and anemia (usually)

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

OLB

  • Not needed in most cases (but may be useful to rule out BOOP)

CXR/Chest CT Patterns

  • Alveolar infiltrates:
    -“Reverse Pulmonary Edema” (”Photographic Negative of Pulmonary Edema”) With Upper Lobe-Predominant Peripheral Infiltrates: occurs in 66% of cases

    • Infiltrates maay be fleeting and may not conform to lobar or segmental boundaries
    • Hilar adenopathy may be seen
    • Similar pattern may be seen in BOOP
  • Interstitial infiltrates: may be superimposed on alveolar infiltrates later in course

Serum IgE

  • Normal-mildly elevated

Circulating Immune Complexes

  • Positive

Clinical

(generally subacute illness that may persist for weeks-months in untreated cases/some cases present with acute respiratory failure)

  • Wheezing: reported in some cases (generally recent onset)
  • Cough: dry or mucoid sputum
  • Dyspnea:
  • Weight loss:
  • Night sweats:
  • Hemoptysis: occasional
  • Fever:
  • Lymphadenopathy:
  • Hepatomegaly:

Treatment

  • Steroids: rapid resolution of symptoms and infiltrates (although mean latency to clinical response is 18 days)
    • Prednisone 30-60 mg/day will result in CXR improvement within 3 days (clearing within 3 weeks)
    • Taper steroids, follow for relapse (may occur)
    • Mean Duration of Therapy: 5 years

Prognosis

  • Long-term prognosis is good

References

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