Klüver Bucy syndrome, unusual consequence of excessively rapid correction of severe hyponatremia

Abstract

Features of Klüver-Bucy syndrome (KBS) include hypersexuality, hyperorality, placidity, visual agnosia, amnesia, hypermetamorphosis, and emotional and nutritional behavior changes. It is a clinical presentation of bitemporal disorders with limbic system abnormalities. The most common cause of KBS is herpes encephalitis. An otherwise healthy 61-year-old woman presented with mental status changes (MMSE-0) after 6 days of severe vomiting. Extracellular dehydration, hyponatremia (107 mmol/L), low levels of natriuresis, and mild hypokalemia were noted. The initial computed tomography (CT) of the brain was normal. Over 36 hours of hospitalization in a district hospital she developed unusual neuropsychiatric disorders: hypersexuality, hyperorality, absence, visual agnosia, sensory aphasia, amnesia, and depression typical of KBS. She was then transferred to a neurology department. Clear improvement was visible 3 months later: MMSE-22, moderation of hypersexuality and hyperorality, partial correction of amnesia and aphasia, regression of visual agnosia. But the prosopagnosia (face blindness) persisted, and the patient remained unable to differentiate positive and negative facial expressions. Intracranial mass, epilepsy, neuromeningeal infection and head trauma were all ruled out. Antiepileptic and antiherpetic agents were tested without success. There was no evidence of adrenal insufficiency or inappropriate vasopressin secretion. Only severe vomiting, corrected by water intake, could explain the hyponatremia. The first MRI showed bitemporal edema; 3 months later it showed large bitemporal lesions, both internal and external, with atrophy of the hippocampus and limbic system. These MRI findings are characteristic of KBS. To our knowledge, this is the only the second case of KBS with bitemporal myelinolysis reported related to excessively rapid correction of hyponatremia (increase of 30 mmol/L over 36 h), which leads more usually to central pontine myelinolysis.