Lateral hypothalamic demyelination and cachexia in a case of "malignant" multiple sclerosis.

A 41-year old woman had profound weight loss and cachexia as a manifestation of rapidly fatal multiple sclerosis. Demyelinating lesions were present in the lateral hypothalamus. Data from animal experiments have indicated that lateral hypothalamic lesions cause a weight loss associated with a lowering of the regulation level or "set-point" for body weight. This case suggests, therefore, that a rapid decline in the level of maintained body weight in a patient without pituitary disease or general organic disorder, or distinct emotional disorder, may represent a clinical manifestation of tissue injury of the lateral hypothalamus.