PURPOSE: Idiopathic acute eosinophilic pneumonia (IAEP) is marked by hypoxemia, pulmonary infiltrates and eosinophilia. It has been associated with young male new-onset smokers. Further research is needed to confirm these associations and better characterize this rare disease.
METHODS: A search of the computerized patient records from January 1, 1997 to October 15, 2010 of patients consenting to research with suspicion of “eosinophilic pneumonia” was conducted. 1060 patients were reviewed. Included patients were 18 or older with an acute febrile illness, hypoxemia or desaturation, diffuse pulmonary infiltrates on chest imaging, and pulmonary eosinophilia demonstrated by biopsy or bronchoalveolar lavage (BAL). Patients were excluded with asthma, drug reaction, autoimmune disease or other known cause of pulmonary eosinophilia. Charts were reviewed for demographics, clinical course, laboratory and imaging findings, and follow-up information.
RESULTS: Seven patients (71% male) met all inclusion criteria with a median age of 61 (range 32-83). Median duration of symptoms was 7 days. Median nadir oxygen saturation was 83%. Patients demonstrated a median white blood cell count of 14.1 units with 0.5 eosinophils. The median BAL eosinophil percentage was 42%. Two patients who demonstrated less than 25% eosinophils on BAL had eosinophils on biopsy and were included. No patients required intubation.
CONCLUSIONS: IAEP is classically described as a febrile illness with pulmonary infiltrates and pulmonary eosinophilia accompanied by desaturation or hypoxia with no demonstrable cause for eosinophilia. As diagnostic methods and pharmacologic knowledge improve, the percentage of patients meeting criteria for IAEP continues to remain small. In addition, our study found that perhaps the current criteria exclude cases of milder presentations with eight patients excluded because they were afebrile, one for symptoms lasting 38 days, one for a remote asthma history, and two for lack of hypoxia only. Contrary to prior reports, none of our patients were new smokers, and there were no instances of respiratory failure requiring intubation.
CLINICAL IMPLICATIONS: Much remains to be learned about this truly rare condition, and current criteria may exclude milder presentations of the disease.
DISCLOSURE: The following authors have nothing to disclose: Shahnaz Ajani, Cassie Kennedy
No Product/Research Disclosure Information