ADULT GROWTH-HORMONE DEFICIENCY

Growth hormone (GH) deficiency should he suspected in adults with eith er hypothalamic or pituitary disease, a history of pituitary or whole brain radiation, or a history of GH treatment during childhood. Clinic al manifestations include abnormal body composition (increased fat, de creased lean mass, and lo iv bone density), reduced exercise ca pacity , and unfavorable lipid profile thigh total and LDL cholesterol, low H DL). Although some GH-deficient adults are asymptomatic, others have n onspecific complaints of fatigue, low energy level, and impairment of memory and concentration. The diagnosis of GH deficiency should be con firmed by at least one provocative test. We define GH deficiency as th e failure of GH to rise above 3 ng/mL in response to an appropriate st imulus, such as insulin-induced hypoglycemia, L-dopa, or arginine. GH replacement should be reserved for patients with documented GI-I defic iency who show no evidence of active malignancy and do not have severe edema or a history of carpal tunnel syndrome. GI-I treatment of the G H-deficient adult has been shown to have positive effects on body comp osition, exercise tolerance, and lipids. In nine placebo controlled st udies in 392 adults using GH doses ranging between 2.6 and 26 mu g per kg per day, mean body fat decreased 4.4% and mean lean body mass incr eased 3.4 kp. These changes were seen after 6 months. increase in hip and spine bone mineral density required longer periods of treatment. G H replacement also has been found to increase maximal oxygen consumpti on, exercise capacity, ventricular ejection fraction, and cardiac outp ut. Improvement in muscle strength has not been demonstrated convincin gly, Most studies have shown reduction in total and LDL cholesterol an d either increased or unchanged I-IDL, GH's effects on psychological p arameters have been difficult to evaluate and require further study Ad verse effects, which are more frequent in patients treated with higher doses of GH, include edema of the hands and feet, arthralgias, myalgi as, and paresthesias of the fingers. These problems diminish or resolv e with dose reduction.In conclusion, GH deficiency in adulthood is rec ognized as a syndrome that may benefit from treatment. GH replacement should, therefore, be considered in individuals with hypothalamic-pitu itary disease who have an abnormal GH response during at least one pro vocative test. Additional studies are needed to determine the conseque nces of long-standing GH deficiency and whether the beneficial effects observed during the first 18 months of GH replacement diminish, plate au, or continue to improve during chronic treatment.