대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

Acute eosinophilic pneumonia

Radiologic Findings

Fig 1. Chest radiography with supine position shows extensive multifocal patchy opacities in both lungs, right more than left.
Fig 2. Chest CT shows diffuse multifocal subpleural or peripheral ground-glass opacities and consolidations with mild smooth interlobular septal thickening in both lungs. Areas of consolidations with air-bronchogram are noted in both lower lobes, predominantly.

3 days later

Brief Review

On the history taking, the patient started smoking several weeks ago. He underwent bronchoscopy and the broncho-alveolar lavage fluid showed increased eosinophils (35%) and no other evidence of infection or allergic disease. He had no peripheral eosinophilia on blood tests. A follow up chest radiography 3 days after corticosteroid treatment showed that infiltrates in both lungs have been cleared (Figure)
Acute eosinophilic pneumonia (AEP) is an uncommon acute respiratory illness of varying severity that includes a presentation as acute respiratory distress syndrome with a fatal outcome. AEP may be idiopathic, but identifiable causes include smoking and other inhalational exposures, medications, and infections. The pathogenesis of AEP is poorly understood but likely varies depending on the underlying cause. Airway epithelial injury, endothelial injury, and release of IL-33 are early events that subsequently promote eosinophil recruitment to the lung; eosinophilic infiltration and degranulation appear to mediate subsequent lung inflammation and associated clinical manifestations. Crucial information for the diagnosis is the demonstration of pulmonary eosinophilia in the BAL fluid and the exclusion of other disease processes that can present with acute pulmonary infiltrates. Although peripheral blood eosinophilia at initial presentation may be a clue in suggesting the diagnosis of AEP, it may be absent or delayed, especially in smoking-related AEP.
Chest radiographic findings of AEP have been reported as bilateral diffuse infiltration with a non-segmental distribution in previous studies. Bilateral areas with GGO and interlobular septal thickening are the most common findings on CT. Bilateral areas of air-space consolidation and thickening of bronchovascular bundles are also seen in more than half of AEP cases. The distribution and zonal predominance are predominantly random or peripheral predominance. Poorly defined air-space nodules or pleural effusion can be seen in some cases.
Optimal management of AEP depends on the recognition and elimination of the underlying cause. The cessation of exposure to the inciting agent (e.g., smoking), and glucocorticoids represent the mainstay of treating AEP of noninfectious origin. If AEP is recognized and treated in a timely manner, the prognosis is generally excellent, with prompt and complete clinical recovery, even in those patients manifesting acute respiratory failure.

References

1) Giacomi FD, Vassallo R, Yi ES, Ryu JH. Acute Eosinophilic Pneumonia. Causes, Diagnosis, and Management. Am J Respir Crit Care Med 2018;197:728-736
2) Jeong YJ, Kim KI, Seo IJ, Lee CH, Lee KN, Kim KN, et al. Eosinophilic Lung Diseases: A Clinical, Radiologic, and Pathologic Overview. Radiographics 2007;27:617-639
3) Cheon JE, Lee KS, Jung GS, Chung MH, Cho YD. Acute Eosinophilic Pneumonia: Radiographic and CT Findings in Six Patients. Am J Roentgenol 1996;167:1675-1199
4) Daimona T, Johkoh T, Sumikawa H, Hondaa O, et al. Acute eosinophilic pneumonia: Thin-section CT findings in 29 patients. Eur J Radio 2008;65:462-467

Keywords

Acute eosinophilic pneumonia,