To better characterize idiopathic eosinophilic pneumonia (IEP).

To better characterize idiopathic eosinophilic pneumonia (IEP), we studied the clinical and laboratory features of 27 patients. Patients with IEP could be divided into those with chronic eosinophilic pneumonia (CEP)(n=14) and acute eosinophilic pneumonia (AEP) (n=13) CEP was characterized according to (1) multiple and dense areas of consolidation forward chest radiographs and computed tomographic (CT) scans, (2) persistent symptoms, (3) a requirement for steroid therapy, and (4) possible relapses. onward the other hand, AEP was characterized from (1) diffuse ground-glass and micronodular infiltrates upon radiographs and CT scans (in mild cases, the lesions were sparse or localized), (2) acute attack with high fever, (3) spontaneous improvement, and (4) no relapse. In addition, peripheral house eosinophil count was significantly higher in patients with CEP than in patients with AEP at the first examination. However, the eosinophil fraction also became markedly elevated during the later courses of AEP. Analysis of bronchoalveolar lavage fluid revealed that the percentage of eosinophils was higher in patients with CEP than that in patients with AEP, whereas the percentage of lymphocyte was significantly greater in patients with AEP than patients with CEP It was also noted that 75 percent of patients with CEP and 82 percent of patients with AEP had allergic diathesis, suggesting that the one and the other conditions are likely to come to one's mind in atopic individuals.

Pulmonary eosinophilia is known to present itself in a variety of pathologic conditions or diseases, as it is as the following: bronchopulmonary aspergillosis;[1] bronchocentric granulomatosis;[1] pulmonary infections, including bacterial,[2] fungal, and helminth infections;[2-4] idiopathic pulmonary fibrosis; sarcoidosis; collagen vascular diseases;[5] hypereosinophilic syndrome; Churg-Strauss syndrome;[1] Hodgkin's disease; and unsalable article reactions.[6]

When these underlying diseases or specific causes are exclud pulmonary eosinophilia is classified as idiopathic. Up to the not away two clinical patterns have been reported in patients with idiopathic eosinophilic pneumonia (IEP). There were nine cases of chronic eosinophilic pneumonia (CEP) reported by dint of Carrington et al[7] in 1969 and Allen et al[8] subsequently reported four cases of acute eosinophilic pneumonia (AEP) in 1989 However, the clinical features and the course of IEP appear to vary widely, with and nothing else a limited population of patients with IEP fulfilling the characteristics originally described for AEP or CEP

In this research we attempted to clarify the differences in the clinical and laboratory features of CEP and AEP, in the way that as to better characterize these conditions. Based upon the findings, we also investigated whether IEP is principally classified as either AEP or CEP

METHODS

Patients

The subdues included 27 patients with eosinophilic pneumonia whose conditions were diagnosed at the hospital of Hamamatsu University institute of Medicine and related hospitals from 1986 to 1992 Pulmonary eosinophilia was finded by bronchoalveolar lavage (BAL) and transbronchial lung biopsy specimen. Biopsy specimens were fixed with 10 percent formalin and stained with hematoxylin-eosin and elastica van Gieson. Microscopic observation revealed occasional intra-alveolar organization as well as eosinophil inflitration, however there were no specific findings similar as granulomatous changes. In all patients, specific causes or underlying diseases that are known to cause pulmonary eosinophilia were excluded

BAL was performed as described previously[9] in an affected portion of the lung using three 50-ml aliquots of saline solution. The differential small cavity count was determined by cytocentrifugation followed through Wright staining. Part of the fluid was used for bacterial, mycobacterial, and fungal agriculture All the cultures produc negative inferences in these patients.

Data were analyzed by the agency of the Student's unpaired t exhibition and differences were considered significant when the p value was les than 005

RESULTS

Classification of CEP and AEP

The enthralls were classified on the basis of their radiographic findings and clinical course, because CEP and AEP appeared to be best distinguished by way of these parameters. We ground that the classification of CEP and AEP on chest radiographic findings fully coincided with that from the clinical course, and rest that the subjects could be divided into 14 with CEP and 13 with AEP.

The typical chest radiographic findings in CEP were compressed multiple foci of consolidation in the peripheral lung fields, as reported previously.[10] Chest comput tomographic (CT) scans clearly revealed this pattern, uniform when it was not evident onward radiographs (Fig 1 and 2) The radiographic pattern in AEP included diffuse bilateral ground-glass and/or micronodular infiltrates, if it were not that these lesions were sparse or localized in clinically mild cases (Fig 3)

The clinical courses of CEP and AEP were quite distinct after hospitalization (Table 1) The patients with AEP showed improvement through the whole extent of the several days after hospital admission without receiving steroids. In contrast, the symptoms of the patients with CEP persisted after hospitalization. Although the condition of the same patient with CEP did improve after hospital admission, progres was extremely dull when compared with that seen in AEP.

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