Hyponatremia in Patients With Multisystem Inflammatory Syndrome in Children.

We report 2 patients with multisystem inflammatory syndrome in children with evidence of hyponatremia on admission. Despite fluid resuscitation and resolution of dehydration, the hyponatremia worsened. Serum and urine studies were evaluated and demonstrated evidence of syndrome of inappropriate antidiuretic hormone. Fluid restriction and anti-inflammatory therapy were initiated with resolution of hyponatremia.