Role of Endocrinology in Hypothalamic Hamartoma Treatment
The main function of the hypothalamus is homeostasis, or maintaining the body's status quo. It is not entirely clear how factors such as blood pressure, body temperature, fluid and electrolyte balance, and body weight are held to a precise value called the set point. Sensory inputs, including taste, smell, and gut distension, all tell the hypothalamus if we are hungry, full, or smelling a steak. Still, how we are able to vary our eating habits day to day while maintaining about the same weight (sometimes despite all efforts to the contrary!) remains a mystery. Although this set point can change over time, from day to day it is remarkably fixed.
The hypothalamus also generates behaviors involved in general arousal, rage, aggression, embarrassment, escape from danger, pleasure, and copulation. This small piece of tissue performs an amazing number of housekeeping chores. Its lateral and anterior parts seem to support activation of the parasympathetic nervous system: decreases in blood pressure and pulse and regulation of digestion, defecation, assimilation, and reproduction. The overall effect contributes to rest and recovery. The medial and posterior hypothalamus regulates activation: acceleration of pulse and breathing rates, high blood pressure, arousal, fear, and anger. Stimulation of specific groups of cells in these areas can elicit pure behaviors.
To regulate these many functions, the hypothalamus must receive inputs about the state of the body and must be able to initiate compensatory changes if needed. Ultimately, the hypothalamus can control every endocrine gland in the body and alter blood pressure (through vasopressin and vasoconstriction), body temperature, metabolism (through thyroid stimulating hormone [TSH]), and levels of adrenaline (through adrenocorticotropic hormone [ACTH]).
Surgery involving the hypothalamus causes profound changes in a patient's hormonal function. Such hormonal changes cause life-changing problems in the regulation of fluid balance, hunger, growth, and response to stress. Fortunately, few patients treated at Barrow have had difficulties with hormone regulation after surgery. Patients who have had problems have been managed by medical replacement of the affected hormone.
Close follow up of hormonal function immediately after surgery and communication with endocrinologists in the home environment are essential as the child recovers from surgery. The role of the pediatric endocrinologist is to evaluate the patient's hormonal status before surgery, assess the effects of surgery on hormonal status after surgery, and plan for follow up for late assessment of hormonal status after full recovery.