The role of flexible bronchoscopy in the diagnostic pathway of children with unexplained peripheral eosinophilia.

Abstract

Many possible underlying causes can be seen in children with unexplained peripheral eosinophilia (UPE) with suspected pulmonary involvement. Here, we aimed to demonstrate the clinical characteristics and diagnoses of children evaluated for UPE who underwent diagnostic bronchoscopy. Thirty-one children who underwent diagnostic bronchoscopy for UPE between 2006-2018 were included. Demographic characteristics, bronchoscopy findings and final diagnosis, and treatments were evaluated. The median age at the time of diagnosis was 5 (0.25-17.5) years. The final diagnoses of 26 patients were as follows: immunodeficiency (n=6); hyper-IgE syndromes (n=4), DOCK8 deficiency + HES (idiopathic hypereosinophilic syndrome; n=1), and severe combined immunodeficiency (n=1), HES (n=3), idiopathic chronic eosinophilic pneumonia (ICEP; n=3), idiopathic pulmonary hemosiderosis (n=1), B cell lymphoma (n=1). In one child, an integrin α3 mutation + cytomegalovirus (CMV) pneumonia was detected. Congenital pneumonia was found in one patient, and parasitic infection in another. In two, eosinophilia was attributed to underlying asthma and atopy. In four, the underlying reasons could not be elucidated. Two children with HES and one with ICEP were lost to follow-up. There was no significant relationship between the peripheral eosinophil count at the time of diagnosis and the percentage of bronchoalveolar lavage eosinophils (BAL). Bronchoscopy contributed to the management of 14 (53.9%) patients. Bronchoscopy has potential diagnostic contribution in patients with UPE suspected of having pulmonary involvement. Numerous various underlying causes may be present in this patient group. There is no relation between peripheral eosinophil count and BAL eosinophil percentage.