Bogazzi F, Bartalena L, Brogioni S, Mazzeo S, Vitti P, Burelli A, Bartolozzi C, Martino E
Istituto di Endocrinologia, University of Pisa, Italy.
Thyroid. 1997 Aug;7(4):541-5. doi: 10.1089/thy.1997.7.541.
Amiodarone-induced thyrotoxicosis (AIT) occurs both in abnormal thyroid glands (nodular goiter, latent Graves' disease) (type I AIT) or in apparently normal thyroid glands (type II AIT). Differentiation of the two forms is crucial, because type I AIT responds well to methimazole and potassium perchlorate combined treatment, whereas type II AIT is effectively managed by glucocorticoids. Differential diagnosis is often difficult, although thyroid radioactive iodine uptake is usually low-to-normal in type I and low-suppressed in type II, and serum interleukin-6 levels are normal/slightly elevated in type I, markedly elevated in type II. Color flow Doppler sonography (CFDS) is a technique that shows intrathyroidal blood flow and provides real-time information on thyroid morphology and hyperfunction. To investigate the usefulness of CFDS in differentiating the two types of AIT, 27 consecutive AIT patients, 11 type I and 16 type II, were evaluated by CFDS before starting antithyroid treatment. Gender, age, severity of thyrotoxicosis, and cumulative amiodarone dose were similar in the two groups. All type II AIT patients had a CFDS pattern 0 (ie, absent vascularity), in agreement with the pathogenesis of the disease, due to thyroid damage. Likewise, nine patients with subacute thyroiditis, another destructive process of the thyroid gland, also had a CFDS pattern 0. Eleven patients with type I AIT had a CFDS pattern ranging from pattern I (presence of parenchymal blood flow with patchy uneven distribution) (7 patients, 64%) to pattern II (ie, mild increase of color flow Doppler signal with patchy distribution) (1 patient, 9%) and pattern III (markedly increased color flow Doppler signal with diffuse homogeneous distribution)(3 patients, 27%), similar to that found in patients with untreated Graves' disease patients, thus indicating a hyper-functioning gland. Control subjects and euthyroid patients under long-term amiodarone treatment had absent thyroid hypervascularity and a CFDS pattern 0. These findings demonstrate that CFDS distinguishes type I and II AIT. Because of its rapidity and noninvasive features, CFDS represents a valuable tool for a quick differentiation between the two types of AIT. This can avoid any delay in initiating the appropriate treatment for a rapid control of thyrotoxicosis in patients whose tachyarrhythmias or other cardiac disorders make thyroid hormone excess extremely deleterious.
胺碘酮所致甲状腺毒症（AIT）可发生于异常甲状腺（结节性甲状腺肿、隐匿性格雷夫斯病）（Ⅰ型AIT）或外观正常的甲状腺（Ⅱ型AIT）。区分这两种类型至关重要，因为Ⅰ型AIT对甲巯咪唑和高氯酸钾联合治疗反应良好，而Ⅱ型AIT则通过糖皮质激素有效控制。鉴别诊断往往困难，尽管Ⅰ型甲状腺放射性碘摄取通常为低至正常，Ⅱ型为低摄取并受抑制，且Ⅰ型血清白细胞介素-6水平正常/轻度升高，Ⅱ型则显著升高。彩色多普勒超声检查（CFDS）是一种显示甲状腺内血流并提供甲状腺形态和功能亢进实时信息的技术。为研究CFDS在鉴别两种类型AIT中的作用，在开始抗甲状腺治疗前，对27例连续的AIT患者进行了CFDS评估，其中Ⅰ型11例，Ⅱ型16例。两组患者的性别、年龄、甲状腺毒症严重程度及胺碘酮累积剂量相似。所有Ⅱ型AIT患者的CFDS表现为0型（即无血管），这与该病的发病机制相符，是由于甲状腺损伤所致。同样，9例亚急性甲状腺炎患者（另一种甲状腺破坏性疾病）的CFDS也为0型。11例Ⅰ型AIT患者的CFDS表现从Ⅰ型（实质血流存在，分布不均）（7例，64%）到Ⅱ型（即彩色多普勒信号轻度增加，分布不均）（1例，9%）和Ⅲ型（彩色多普勒信号显著增加，分布均匀）（3例，27%），与未治疗的格雷夫斯病患者相似，表明甲状腺功能亢进。对照组和长期接受胺碘酮治疗甲功正常的患者甲状腺无血管增多，CFDS表现为0型。这些发现表明CFDS可区分Ⅰ型和Ⅱ型AIT。由于其快速性和非侵入性特点，CFDS是快速区分两种类型AIT的有价值工具。这可以避免在对快速性心律失常或其他心脏疾病患者中甲状腺激素过量极其有害的情况下，因启动适当治疗以快速控制甲状腺毒症而出现任何延误。
