Hyponatremia With Herpes Simplex Encephalitis: Possible Relationship of Limbic Lesions and ADH Secretion

Introduction This report describes a patient with herpes simplex encephalitis who exhibited, during the acute stage of his illness, severe, transient hyponatremia with renal sodium loss presumably induced by inappropriate and excessive production of antidiuretic hormone. Although this syndrome often referred to as "cerebral salt wasting" 1-3 has been seen in patients with various brain lesions, 4-6 this is the first instance, to our knowledge, where it has been associated with verified herpes simplex encephalitis. This patient is still alive, and the exact topography of his cerebral lesion cannot be precisely delineated. Nonetheless, the clinical picture and ancillary diagnostic studies are compatible with a bilateral diffuse encephalopathy involving predominantly hippocampal and adjacent mesial temporal regions. Because of the predilection of herpes simplex encephalitis for producing destructive lesions in those regions of the brain comprising the "limbic system" 7-9 we have discussed the relationship of the limbic system and the hypothalamic-postpituitary