Section of Endocrinology, Marshall University School of Medicine, Huntington, West Virginia 25701, USA.
Endocr Pract. 2010 Jul-Aug;16(4):686-91. doi: 10.4158/EP10011.RA.
To propose an approach for the diagnosis of secondary adrenal insufficiency (AI) by presentation of 2 clinical cases and review of the literature.
We describe 2 patients who were considered to have a normal hypothalamic-pituitary-adrenal axis on the basis of an appropriate response to the high-dose (250 microg) cosyntropin stimulation test (HST), with use of a cutoff value of 20 microg/dL. Our first patient had undergone resection of a 4-cm pituitary tumor a few months previously, and the second patient had hyponatremia with empty sella syndrome. Both patients, however, had strong clinical evidence suggestive of secondary AI. On testing by the insulin tolerance test (ITT) in the first patient and the overnight metyrapone test (OMT) in the second patient, secondary AI was diagnosed. We reviewed the literature to compare the utility of the different tests for the diagnosis of secondary AI.
An 8 AM serum cortisol value less than 5 microg/dL or above 13 microg/dL and a stimulated cortisol level less than 16 microg/dL on both the low-dose cosyntropin stimulation test (LST) and the HST as well as above 22 microg/dL on the LST and above 30 microg/dL on the HST can reliably predict the functional status of the hypothalamic-pituitaryadrenal axis in chronic secondary AI. Values between these cutoff points may necessitate further assessment with the OMT or ITT based on clinical suspicion.
We recommend a 3-step diagnostic approach, with the first 2 steps performed together-starting with the 8 AM basal cortisol determination in conjunction with either the LST (preferably) or the HST. In cases of an indeterminate response coupled with a strong clinical suspicion, the final step should be definitive testing with the OMT or ITT.
通过介绍 2 个临床病例并复习文献，提出一种诊断继发性肾上腺功能不全（AI）的方法。
我们描述了 2 例患者，他们被认为在适当的高剂量（250μg）促皮质素刺激试验（HST）下，基于对下丘脑-垂体-肾上腺轴的正常反应，使用 20μg/dL 的截断值。我们的第一个患者在几个月前接受了 4cm 垂体肿瘤切除术，第二个患者患有低钠血症伴空蝶鞍综合征。然而，这两个患者都有强烈的临床证据表明存在继发性 AI。第一个患者接受胰岛素耐量试验（ITT）和第二个患者接受 overnight metyrapone 试验（OMT）检查，诊断为继发性 AI。我们回顾了文献，比较了不同试验诊断继发性 AI 的效用。
8 点时血清皮质醇值低于 5μg/dL 或高于 13μg/dL，低剂量促皮质素刺激试验（LST）和 HST 时的刺激皮质醇水平低于 16μg/dL，LST 时高于 22μg/dL，HST 时高于 30μg/dL，可以可靠地预测慢性继发性 AI 下丘脑-垂体-肾上腺轴的功能状态。在这些截断值之间的数值可能需要根据临床怀疑进一步评估 OMT 或 ITT。
我们建议采用 3 步诊断方法，前 2 步同时进行-首先进行 8 点基础皮质醇测定，同时进行 LST（最好）或 HST。在反应不确定且临床怀疑强烈的情况下，最后一步应进行 OMT 或 ITT 的明确测试。
