Hyponatremia: A Marker of Inflammation for COVID-19

We have read with great interest the article by Nair et al[1] in which they explain the presence of two subphenotypes of acute respiratory distress syndrome (ARDS) secondary to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) through serum markers of systemic inflammation such as ferritin (ferritin), serum lactate dehydrogenase (LDH) and C-reactive protein (CRP), which are associated with worse results in terms of days of stay in the intensive care unit (ICU), days of mechanical ventilation, and higher mortality; interleukin-6 (IL-6) is the proinflammatory cytokine involved in the cascade of systemic damage. Therefore we share our experience and research on the other side of the world: under the premise that elevated serum levels of IL-6[2] favor non-osmotic secretion of antidiuretic hormone (ADH) with the consequent presence of hyponatremia this electrolyte disturbance could be another marker of severity and poor prognosis; therefore, SARS-CoV-2 would be the etiological agent in which the IL-6 released is recognized as the main inflammatory mediator of the acute phase with hematological, immunological, endocrinological, and metabolic effects.[3]