Since Ranson’s experimental work, it has been appreciated that acute lesions in the posterior and lateral parts of the hypothalamus may be associated with stupor, although it has always been difficult to determine the precise structures involved. One can be certain that permanent coma from small lesions in the caudal diencephalon (thalamus) may occur in the absence of any changes in the hypothalamus and, conversely, that chronic hypothalamic lesions may be accompanied by no more than drowsiness, confusion or no mental change at all.
Among the cases of acquired changes in personality and sleep patterns from ventral hypothalamic disease that we have seen, a few have shown an impressive tendency toward a hypomanic, hypervigilant state with insomnia, lasting days on end, accompanied by an impulsiveness and disinhibition suggestive of involvement of the frontal connections to the hypothalamus. In one patient we examined following removal of a craniopharyngioma, a delirious, agitated state lasted 3 weeks during which time attention could not be captured for even a moment. These and other cognitive disorders with hypothalamic lesions are difficult to interpret and are usually transient. Often the lesions are acute or postoperative and involve adjacent areas, making it impossible to attribute them to the hypothalamus alone.
Kleine in 1925 and Levin in 1936 described an episodic disorder characterized by somnolence and overeating. For days or weeks, the patients, mostly adolescent boys, sleep 18 or more hours a day, waking only long enough to eat and attend to toilet needs. They appear dull, often confused, and restless, and are sometimes troubled by hallucinations. The hypothalamus has been implicated on the basis of these symptoms, but without definite pathologic confirmation. Further discussion can be found in Chap. 18.
Loss of function of the anterior pituitary gland may result from disease of the pituitary itself or from hypothalamic disease. In either event, it leads to a number of clinical abnormalities, each predicated on the deficiency of one or more hormones that depend on the pituitary trophic factors described earlier. The condition of panhypopituitarism is a serious illness that requires supplementation with multiple hormones. Hypopituitarism may have its onset in childhood, either as an inherited process that affects individual or multiple hormones or as a secondary process caused by a destructive lesion of the pituitary or the hypothalamus from tumor, for example, craniopharyngioma. Later in life the causes vary, but the most common are pituitary surgery, infarct of the gland from a rapidly growing adenoma (pituitary apoplexy, see Chap. 30), involutional changes that occur at the end of pregnancy (Sheehan syndrome), cranial irradiation for cerebral tumors other than those in the pituitary fossa, lymphocytic hypophysitis, and granulomatous and neoplastic invasion.
The clinical features of pituitary failure vary, but impairments of thyroid function tend to be more prominent than those of adrenal failure. The neurologic accompaniments of pituitary failure depend on the underlying cause; Lamberts and colleagues have reviewed the endocrinologic aspects and a detailed discussion can be found in Harrison’s Principles of Internal Medicine.
Neuroendocrine Syndromes Related to the Adrenal Glands (See Also Chap. 30)