Syndrome of inappropriate
antidiuretic hormone secretion (
SIADH) is one of the common causes of euvolemic
hyponatremia (serum Na+ < 135 mEq/L) in hospitalized children. It is characterized by increased serum ADH, leading to water retention via its action on
V2 receptors in the distal renal tubules. Various conditions such as
pain, the postoperative state, drugs,
central nervous system infections,
tumors, malformations, and
pneumonia can predispose a person to
SIADH. The conventional treatment of
SIADH includes fluid restriction and
salt supplementation. Occasionally, this may fail to control
hyponatremia, mandating pharmacological
therapy. V2-receptor antagonists are an FDA-approved
therapy for adults with euvolemic and hypervolemic
hyponatremia. However, there is limited experience with their use in the pediatric population. Here, the authors present a girl with
corpus callosum agenesis with severe symptomatic
hyponatremia due to
SIADH who was successfully managed with the V2-receptor antagonist
tolvaptan.