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

OBJECTIVES

To identify clinical characteristics that may lead to the early recognition of patients admitted to the hospital 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 admitted to the hospital 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 analyzed. A comparison was made between those patients that met urine SIADH criteria and those who did not.

RESULTS

A total of 126 children were included, and 23 (18.6%) of them had 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 nebulized 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 one month with acute moderate bronchiolitis and urine SIADH criteria have worse clinical courses and more need for non-invasive mechanical ventilation, PICU admission, and have a higher incidence of pneumonia on chest X-ray. For that reason, it is recommended to collect a urine sample from these patients to allow an early diagnosis of SIADH, and thus early treatment of fluid and electrolyte abnormalities.