Common finding of mild hyponatremia in children evaluated at the Emergency Department and its correlation with plasma C-reactive protein values

Background: In the context of infectious diseases, mild hyponatremia is supposed to be originated by a transient secretion of vasopressin mediated by non-osmotic stimuli. This study provides data supporting the view that mild hyponatremia during acute illnesses is related to a systemic inflammatory condition. Methods: A total of 328 consecutive children (aged 3 months to 17 years) underwent blood testing at the Pediatric Emergency Department over a 2-month period and were retrospectively analyzed. Results: Hyponatremia was found in 98 patients, and in most of them it was a mild condition. A significant trend towards lower levels of plasmatic sodium, along with the increase of C-reactive protein, was observed. Conclusions: A significant relationship between plasmatic sodium levels and C-reactive protein was found, apart from of the underlying disease.