Hyponatremia in Psychiatric Patients: Update on Evaluation and Management

Abstract

Hyponatremia (serum sodium concentration < 136 mEq/L) is a prevalent and potentially dangerous medical comorbidity in psychiatric patients. MEDLINE was used to identify peer-reviewed publications that described the role of arginine vasopressin (AVP) in the pathogenesis of hyponatremia, the presentation and treatment of hyponatremia in psychiatric patients, and promising new treatment options. Polydipsia may lead to hyponatremia in patients with schizophrenia, which is mediated, in part, by a reduced osmotic threshold for the release of AVP and by a defect in the osmoregulation of thirst. Acute-onset hyponatremia may require emergent treatment with hypertonic (3%) saline, whereas chronic cases mandate gradual correction to minimize the risk of osmotic demyelination. The AVP-receptor antagonists, including conivaptan, tolvaptan, lixivaptan, and satavaptan, represent a therapeutic advance in the treatment of dilutional hyponatremia. Based on the role of AVP in the development of hyponatremia, further studies are warranted to determine the efficacy of the AVP-receptor antagonists in psychiatric patients with hyponatremia.