Eosinophilic lung diseases include a variety of conditions ranging from tropical eosinophlia to drug reactions. Acute eosinophilic pneumonia (AEP) is a rare disease usually characterized by respiratory failure and alveolar infiltration with eosinophils. We describe a series of US military personnel who developed AEP while deployed.
We identified military personnel diagnosed with AEP while serving in Operations Iraqi Freedom and Enduring Freedom (OIF/OEF). After a retrospective evaluation (March –June 2003), prospective surveillance commenced in July 2003. We defined AEP based on the acute onset of pulmonary infiltrates coupled with either pulmonary eosinophilia or peripheral eosinophilia. We required that known causes of eosinophilia be excluded. Endpoints included: epidemiologic features, need for mechanical ventilation(MV), and mortality.
Between March 2003 and March 2004, 17 cases were identified yielding an estimated annualized incidence of 9.7 per 100,000 person-years. The majority of subjects (88%) were male and the median age was 23 years (range 20-43). Six subjects underwent bronchoalveolar lavage (median eosinophilia of 41%). All subjects developed peripheral eosinophlia (range 8% to 42%). There was no geographic or temporal clustering of cases. An extensive search for known causes of pulmonary eosinophilia (e.g., drug exposures, parasitic disease) did not identify any secondary etiologies. All patients used tobacco with 2/3rds recently beginning to smoke. MV was required in 71% for a median of 7 days (range: 2 to 16 days). Two soldiers died. The remainder responded to corticosteroids. Twelve individuals were re-evaluated a median of 3 months after diagnosis. At this point subjects were: off treatment and had either normal or nearly normal spirometry. None had recurrent eosinophilia or developed chronic eosinophilic pneumonia.
The rate of AEP appears high in this population of otherwise healthy subjects and not all suffer fulminant respiratory failure. Corticosteroids if initiated promptly appear effective.
Physicians caring for soldiers returning from OIF/OEF should consider AEP in patients who develop pneumonia. Early use of bronchoscopy may aid in identification of cases.
A.F. Shorr, None.