Endocrine Abnormalities

Craniopharyngiomas usually affect hormonal secretion by direct compression or destruction of the hypothalamus or pituitary stalk. Direct mass effect on the pituitary gland itself can also occur, but pure intrasellar craniopharyngiomas are rare. Hor monal abnormalities occur in 43% to 90% of patients at diagnosis.48 All of the adenohypophyseal hormones can be affected, including growth hormone; luteinizing hormone (LH) or follicle-stimulating hormone (FSH); adrenocorticotropic hormone (ACTH); and thyroid stimulating hormone. Deficiencies in LH and FSH lead to delayed or arrested puberty in adolescents, loss of libido, or secondary amenorrhea in adults. Low growth-hormone levels will result in growth retardation and delayed bone age. Hypothyroidism leads to poor growth, weight gain, cold intolerance, and fatigability. Forty percent of children demonstrate decreased height velocity or short stature at diagnosis, either from growth-hormone deficiency, central hypothy-roidism, delayed puberty, or a combination of these three. Impingement on the pituitary stalk leads to decreased amounts of prolactin inhibitory factors such as dopamine. This "stalk effect" results in hyperprolactinemia. In Fahlbusch's reported data, pre-operative endocrine dysfunction was more common than the symptoms suggested: hypogonadism, 77%; hyperprolactinemia, 41%; adrenal failure, 32%; hypothyroidism, 25%; and diabetes insipidus, 16%.17 In the subset of pediatric patients (n = 30), the preoperative endocrine abnormalities were similar, except hypogonadism, which was more common (91%), and hyperprolactinemia (17%) and diabetes insipidus (10%), which were less common. Lastly, some children have "hypothalamic obesity" caused by damage of the ventromedial hypothalamus (VMH), with resultant dysregulation of energy balance.28,40,41

Any hormonal deficiency should be evaluated and treated before definitive treatment. A complete endocrinologic assessment is necessary before surgery and is invaluable when varying degrees of endocrine dysfunction may develop (Table 95-1). All patients should receive stress-dose steroids before surgery on the assumption that normal ACTH regulation is blunted. Hypothyroidism can take several days to correct and therapy should be begun preoperatively. However, adrenocor-ticoid insufficiency can be precipitated if thyroid replacement is begun before steroid is given. Any electrolyte abnormalities should also be identified and corrected before surgery.

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