THE PITUITARY AND HYPOTHALAMIC REGION IN CHRONIC EPIDEMIC ENCEPHALITIS

Abstract

In chronic epidemic encephalitis there is frequently some change in the pituitary. The hypothalamic region of the brain in chronic epidemic encephalitis is more severely affected than any other area except the substantia nigra of the mid-brain. The changes in the two regions are usually, but not invariably, parallel. In all the cases of epidemic encephalitis the changes in the hypothalamic region were greater than in the same area in brains from cases of Huntington's chorea and general paralysis of the insane, where elsewhere there were severe degenerative changes. Severe lesions in the hypothalamic region do not give rise to diabetes insipidus nor to obesity, but less intense lesions may cause these conditions. The part played by the pituitary in the production of obesity remains uncertain. Cachexia is probably independent of any changes in the pituitary. There is no absolute proof, although there is a possibility, that pathological alterations in the hypothalamic region are the cause of cachexia. On the other hand, it seems certain there is no causal relationship between destruction of the substantia nigra and cachexia. There is not any definite relationship between disturbances of sleep in epidemic encephalitis and alterations in the anterior lobe of the hypophysis. As the hypothalamus was affected in all the brains, and is not commonly the chief site of attack in other degenerative diseases, disturbance of its function—perhaps due to increase of calcium salts—probably plays some share in the causation of disorders of sleep. An increase of calcium salts does not usually occur in conditions such as Huntington's chorea and general paralysis of the insane. Hæmorrhages were more common in the hypothalamic region and mid-brain than elsewhere, and may have been the cause of sudden death in one young patient.