Growth hormone (GH) deficiency should be suspected in adults with either hypothalamic or pituitary disease, a history of pituitary or whole brain radiation, or a history of GH treatment during childhood. Clinical manifestations include abnormal body composition (increased fat, decreased lean mass, and low bone density), reduced exercise capacity, and unfavorable lipid profile (high total and LDL cholesterol, low HDL). Although some GH-deficient adults are asymptomatic, others have nonspecific complaints of fatigue, low energy level, and impairment of memory and concentration. The diagnosis of GH deficiency should be confirmed by at least one provocative test. We define GH deficiency as the failure of GH to rise above 3 ng/mL in response to an appropriate stimulus, such as insulin-induced hypoglycemia, L-dopa, or arginine. GH replacement should be reserved for patients with documented GH deficiency who show no evidence of active malignancy and do not have severe edema or a history of carpal tunnel syndrome.GH treatment of the GH-deficient adult has been shown to have positive effects on body composition, exercise tolerance, and lipids. In nine placebo-controlled studies in 392 adults using GH doses ranging between 2.6 and 26 mu;g per kg per day, mean body fat decreased 4.4percnt; and mean lean body mass increased 3.4 kg. These changes were seen after 6 months. Increase in hip and spine bone mineral density required longer periods of treatment. GH replacement also has been found to increase maximal oxygen consumption, exercise capacity, ventricular ejection fraction, and cardiac output. Improvement in muscle strength has not been demonstrated convincingly. Most studies have shown reduction in total and LDL cholesterol and either increased or unchanged HDL. GH's effects on psychological parameters have been difficult to evaluate and require further study.Adverse effects, which are more frequent in patients treated with higher doses of GH, include edema of the hands and feet, arthralgias, myalgias, and paresthesias of the fingers. These problems diminish or resolve with dose reduction.In conclusion, GH deficiency in adulthood is recognized as a syndrome that may benefit from treatment. GH replacement should, therefore, be considered in individuals with hypothalamic-pituitary disease who have an abnormal GH response during at least one provocative test. Additional studies are needed to determine the consequences of long-standing GH deficiency and whether the beneficial effects observed during the first 18 months of GH replacement diminish, plateau, or continue to improve during chronic treatment.
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