Drug-Induced Eosinophilic Pneumonia

Fig.1: Chest radiograph of a 49-year-old woman, presenting with low-grade fever and cough for a month, shows patchy airspace opacities in both upper lobes.
Fig2&3: Axial CT images show asymmetric patchy consolidations and groundglass opacities mainly in the periphery of the upper lobes and superior segments of the lower lobes.

Differential Diagnosis of Subacute Bilateral Upper Lobe Airspace Opacities

• Cryptogenic organizing pneumonia (COP)
• Churg-Strauss syndrome (vasculitis)
• Pulmonary infarction
  

Eosinophilic Lung Disease

• A group of disorders characterized by 1) abnormal lung opacities with peripheral eosinophilia, 2) tissue eosinophilia confirmed at either open or transbronchial lung biopsy, or 3) increased eosinophil in bronchoalveolar lavage (BAL) fluid
  
• Known causes: asthma, infection (coccidiodomycosis, PCP, mycobacteria), tumor (NSCLC, lymphoma, lymphocytic leukemia), collagen vascular disease (RA, Wegener's, IPF, LCH) and drugs

Drugs Associated with Eosinophilic Lung Disease

• Amiodarone,
  
• Methotrexate,
  
• Nitrofurantoin,
  
• Phenytoin,
  
• B-blockers,
  
• Iodinated contrast media,
  
• ACE inhibitor

Pattern of Abnormalities in Chest CT

• Bilateral, asymmetric, peripheral consolidations and groundglass opacities
  
• Upper lung zone > random > lower
  
• Ancillary findings: centrilobular nodules, reticulations, septal thickening
  

Our case is an eosinophilic pneumonia (confirmed by BAL fluid eosinophilia) associated with Minocycline, which had been improved after a short course of corticosteroid therapy.

Reference:
1. Souza CA, et al. Drug-induced eosinophilic pneumonia: high-resolution CT findings in 14 patients. AJR 2006;186:368-373.
2. Jeong YJ, et al. Eosinophilic lung diseases: a clinical, radiologic, and pathologic overview. Radiographics 2007;27:617-637.