Popovic V
Institute of Endocrinology, University Clinical Center, Belgrade, Serbia.
J Endocrinol Invest. 2005;28(11 Suppl International):73-4.
In acromegaly, clinical features are of the utmost importance, and biochemical confirmation is rarely difficult. However, some clinically manifest acromegalics have subtle abnormalities in GH secretion resulting in post-glucose GH nadir in the designated "normal" range with high IGF-I levels. Clinical decision may be based on the probability of the disease and elevated IGF-I levels. The TRH test or the frequent GH sampling test may help confirm acromegaly but on their own have no diagnostic advantage. A TRH-GH response is not specific to acromegaly, while frequent sampling is not practical. Other tests rarely add information beyond that obtained by usual investigations. Post-treatment assessment of the disease activity and definition of acromegaly cure, by measuring GH secretion, remain problematic. IGF-I levels seem to differentiate normality less clearly and discordance of GH and IGF-I results is frequent. Post-treatment probability for residual disease activity should include more clinical parameters such as insulin sensitivity, leptin and echocardiography. Furthermore, with efforts to achieve tight biochemical control of the disease it is foreseeable that a proportion of patients may be rendered GH deficient, requiring stimulatory testing. Acromegaly is a disfiguring and disabling illness, in which by definition, the disorder is caused by a pituitary GH-secreting adenoma resulting in high circulating levels of GH and IGF-I. The clinical features of acromegaly include those of GH and IGF-I on tissues and the effects of the pituitary tumor itself. There is no single cut-off value for GH with perfect discrimination between acromegaly and normality. The recommended post-glucose GH nadir value of 1 microg/l is now considered to be inappropriately high, and measurement of IGF-I levels although extremely valuable has its limitations. Furthermore, some acromegalics may have subtle abnormalities in GH secretion, resulting in post-glucose GH nadir in the designated "normal" range with elevated IGF-I levels.
在肢端肥大症中，临床特征至关重要，生化确诊很少有困难。然而，一些临床表现为肢端肥大症的患者生长激素（GH）分泌存在细微异常，导致葡萄糖负荷后GH最低点处于指定的“正常”范围内，但胰岛素样生长因子-I（IGF-I）水平却很高。临床决策可能基于疾病的可能性和升高的IGF-I水平。促甲状腺激素释放激素（TRH）试验或频繁的GH采样试验可能有助于确诊肢端肥大症，但仅凭它们本身并无诊断优势。TRH-GH反应并非肢端肥大症所特有，而频繁采样又不实用。其他检查很少能提供比常规检查更多的信息。通过测量GH分泌对疾病活动进行治疗后评估以及确定肢端肥大症的治愈情况仍然存在问题。IGF-I水平似乎不太能明确区分正常情况，且GH和IGF-I结果不一致的情况很常见。治疗后残留疾病活动的可能性应纳入更多临床参数，如胰岛素敏感性、瘦素和超声心动图。此外，随着努力实现对该疾病的严格生化控制，可以预见一部分患者可能会出现GH缺乏，需要进行刺激试验。肢端肥大症是一种毁容性和致残性疾病，根据定义，该疾病由垂体分泌GH的腺瘤引起，导致循环中GH和IGF-I水平升高。肢端肥大症的临床特征包括GH和IGF-I对组织的作用以及垂体肿瘤本身的影响。对于GH，没有一个单一的临界值能完美地区分肢端肥大症和正常情况。目前推荐的葡萄糖负荷后GH最低点值1μg/L被认为过高，而IGF-I水平的测量虽然极具价值但也有其局限性。此外，一些肢端肥大症患者可能存在GH分泌的细微异常，导致葡萄糖负荷后GH最低点处于指定的“正常”范围内，但IGF-I水平升高。
