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

Abstract

BackgroundMany 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.MethodsThirty‐one children who underwent diagnostic bronchoscopy for UPE between 2006–2018 were included. Demographic characteristics, bronchoscopy findings and final diagnosis, and treatments were evaluated.ResultsThe 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.ConclusionsBronchoscopy 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.

From evidence to practice: A systematic review‐based diagnostic algorithm for paediatric eosinophilia across socioeconomic context

“…All the studies were observational: five were cross-sectional, [17][18][19][20][21] and there were four prospective [22][23][24][25] and six retrospective cohort studies. 2,5,9,[26][27][28] The quality of the studies, evaluated through the National Heart, Lung, and Blood Institute Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies, is reported in Appendix S1-figure A1.…”

“…Overall, 3409 children with eosinophilia were assessed; the median age ranged from 2.8 to 16.2 years and the median percentage of males was 56.5%. 19,21 Most of the studies were conducted in high-or upper to middle-income countries (three in the USA, 2,5,9 three in Turkey, 21,27,28 F I G U R E 1 Flow diagram of literature search and data extraction.…”

“…24 Furthermore, variations in the definition used for eosinophilia were noted. Most authors used a cut-off value of AEC > 500/μL in peripheral blood to define eosinophilia, 2,17,[19][20][21]25,26,28 while two studies employed a lower threshold of 450/μL. 18,23 Excluding studies with cohorts restricted to eosinophilic children, the prevalence of absolute eosinophilia varied from 17.4% to 77.2%.…”

“…17,22 Immune disorders were assessed exclusively in children living in middle-to high-income countries, and the prevalence ranged from 1.2% to 8.3%. 2,5,9,21,27,28 Similarly, hypereosinophilic syndrome was found in 46% of the children living in the USA evaluated in a third-level paediatric centre for persistent, unexplained hypereosinophilia. 9 were reported with a prevalence of 1.2% each.…”

“…Interestingly, almost half of the assessed patients were born within consanguineous marriages (46.2%). 28 Eight studies failed to ascertain the underlying cause of eosin-…”