[Association between moderate-severe bronchiolitis and syndrome of inappropriate antidiuretic hormone secretion in emergency departments].

Abstract Objectives To identify clinical characteristics that may lead to the early identification of patients hospitalised for moderate-to-severe bronchiolitis with urine results associated with the syndrome of inappropriate antidiuretic hormone secretion (SIADH). Patients and methods A prospective observational study was conducted, spanning the bronchiolitis epidemic season (October 2012–March 2013), including all children who were hospitalised with a diagnosis of moderate-to-severe bronchiolitis. The following criteria were used to establish a diagnosis of SIADH: urine sodium level of 40 mmol/L or greater, urine osmolarity above 500 mosm/kg, and urine density of 1020 g/L or greater. Demographic characteristics, ventilation mode and clinical outcome were also analysed. A comparison was made between patients that met urine SIADH criteria and those that did not. Results A total of 126 children were included, 23 (18.6%) with urine SIADH criteria. Patients in this group had a higher incidence of pneumonia and/or atelectasis on chest X-ray (21.7% vs. 1.9%, p  = .002), worse response to bronchodilator treatment with nebulised adrenaline (69.5% vs. 28,1%, p  = .016), more need for respiratory assistance (high flow oxygen therapy (17.4% vs. 7.7%, p  = .016)), or non-invasive mechanical ventilation (13% vs. 5.8%, p  = .034), and more admissions to the PICU (26.1% vs. 6.8%, p  = .007). Conclusions Patients older than 1 month with acute moderate bronchiolitis and urine SIADH criteria present poorer progress and greater need for non-invasive mechanical ventilation, PICU admission, and a higher incidence of pneumonia on chest X-ray. For this reason, urine samples should be collected from these patients for early diagnosis of SIADH, and thus early treatment of fluid and electrolyte abnormalities.