Acute eosinophilic pneumonia associated with non-cigarette smoking products: a systematic review

Acute eosinophilic pneumonia (AEP) is characterized by an acute onset respiratory illness with bilateral chest infiltrates and evidence of pulmonary eosinophilia. Cigarette smoking is the main risk factor, but drugs and other inhalational exposures have also been reported. Herein, the association between AEP and smoking devices other than cigarettes is reviewed The PubMed database was searched using terms such as "smoking", "vaping", "e-cigarette", "waterpipe", and "marijuana", along with other commonly used synonyms for these terms. In addition, eosinophilic lung diseases were also searched for using the same database. All cases of AEP were identified using the modified Philit criteria in association with the use of marijuana, waterpipe, e-cigarettes or heat-not-burn cigarettes. Cases associated with illicit drug use were excluded. Twelve cases were included with amedian age of 20 (15-60). 75% of patients studied were male. Exposures included marijuana smoking (n = 5), waterpipe usage (n = 2), heat-not-burn cigarette use (n = 2), e-cigarette use (n = 2) and synthetic cannabinoid use (n = 1). Arecent change in smoking habits was reported in 50% of patients. Presenting symptoms were dyspnea (91.6%), cough (66.6%), fever (66.6%) and chest pain (25%). 90% of patients had leukocytosis on presentation, but only 16.6% had peri-pheral eosinophilia. The median eosinophil percentage in bronchoalveolar lavage was 67.5% (0 to 78). Two patients had alung biopsy performed. Bilateral involvement on chest imaging was reported in all patients. Five patients (41.6%) required invasive mechanical ventilation and ten patients (83.3%) were treated in an intensive care unit. All patients responded to corticosteroid therapy with no relapses reported. Acute eosinophilic pneumonia is reported with smoking that does not include traditional cigarette smoking such as waterpipes, e-cigarettes, heat-not-burn cigarettes, and marijuana and can have asimilar presentation and clinical course.