A Case of Transient Hypercortisolism Simultaneously Occurring With the Syndrome of Inappropriate Antidiuretic Hormone Secretion Induced by Olanzapine

Abstract

We herein present a case of a 71-year-old woman who was referred to our hospital with the prolonged disturbance of consciousness after two convulsive seizures the day before admission. She was in longterm hospitalization because of schizophrenia. Blood tests showed severe low-osmolar hyponatremia (Osm: 226 mOsm/kg and Na: 110.3 mEq/L) and hypokalemia (K: 2.67 mEq/L). An endocrine examination revealed that the syndrome of inappropriate antidiuretic hormone secretion (SIADH), which was induced secondary to olanzapine, and transient hypercortisolism had simultaneously occurred. Low-and high-dose overnight dexamethasone suppression tests and the corticotropin-releasing hormone (CRH) test showed similar endocrine responses to those in patients with Cushing's syndrome. However, no abnormality in the pituitary gland was detected using contrast magnetic resonance imaging (MRI). After admission, elevated adrenocorticotropic hormone (ACTH) and cortisol levels gradually decreased and normalized by the time of discharge. Transient hypercortisolism sometimes occurs in patients with schizophrenia. Hypercortisolism in the present case was considered to be induced by stress such as severe hypo-osmotic hyponatremia and convulsions in addition to the underlying disorder of schizophrenia. Clinicians need to routinely check electrolytes in patients taking olanzapine in order to prevent insidious progression to severe hyponatremia. To the best of our knowledge, this is the first case report in which an endocrine examination and its interpretation were performed for SIADH accompanied by transient hypercortisolism due to the stimulation of ACTH.