Zettinig Georg, Asenbaum Susanne, Fueger Barbara J, Hofmann Andrea, Diemling Markus, Mittlboeck Martina, Dudczak Robert
Department of Nuclear Medicine, University of Vienna, Austria.
Clin Endocrinol (Oxf). 2003 Nov;59(5):637-43. doi: 10.1046/j.1365-2265.2003.01901.x.
Hashimoto's encephalitis is a term which describes encephalopathy associated with autoimmune thyroiditis, but it is not based on evidence, whether Hashimoto's encephalitis is a distinct clinical entity by itself. In previously reported cases of Hashimoto's encephalitis, abnormal brain perfusion studies have been reported. The aim of this study was to evaluate the prevalence of brain perfusion abnormalities in euthyroid patients with autoimmune thyroiditis.
99mTc Ethyl cystein dimer (ECD) single photon emission computed tomography (SPECT) studies were performed in a study group of 41 euthyroid patients with autoimmune thyroiditis and a matched control group of 35 healthy individuals. All study participants had a normal neurological investigation and a detailed neurological history taking. Individuals with known or suspected morphological brain abnormalities were excluded from the study. Zung's Self-Rating Anxiety Scale (SAS) and Zung's Self-Rating Depression Scale (SDS) were used to detect depression and mood disorders. Automatic quantification of perfusion was performed with both a voxel-based analysis as well as a volume-of-interest (VOI) based analysis of 46 predefined cortical and subcortical regions. The findings from both groups were compared to a reference template.
In the voxel-based analysis, there was a significant difference between patients and controls in the mean volume of perfusion defects deviating 2SD below the normal values (21.8 ml vs. 10.4 ml; P = 0.02). Hyperperfused areas, however, did not differ significantly between study patients and controls. A significant correlation of the perfusion defects with time since diagnosis of autoimmune thyroiditis was seen (r = 0.42). In the VOI-based analysis, abnormal regions were more frequent in the study group when compared to controls (P < 0.01) However, no topographic pattern was apparent. Regarding neurological findings, no significant difference was found between study patients and controls. However, both the SAS and SDS scores differed significantly between the two groups, but there was neither a correlation between the two scores and perfusion abnormalities nor an association with depression in our study group.
These findings of impaired brain perfusion in patients with autoimmune thyroiditis further strengthen the hypothesis of a possible cerebral involvement in autoimmune thyroiditis in individual cases. The presence of cerebral hypoperfusion suggests a cerebral vasculitis as the most likely pathogenetic model.
桥本脑病是一个用于描述与自身免疫性甲状腺炎相关的脑病的术语，但尚无证据表明桥本脑病本身是否为一种独特的临床实体。在先前报道的桥本脑病病例中，曾有脑灌注异常的报告。本研究的目的是评估自身免疫性甲状腺炎的甲状腺功能正常患者中脑灌注异常的发生率。
对41例自身免疫性甲状腺炎的甲状腺功能正常患者组成的研究组和35名健康个体组成的匹配对照组进行了99mTc 乙基半胱氨酸二聚体（ECD）单光子发射计算机断层扫描（SPECT）研究。所有研究参与者均进行了正常的神经学检查并详细询问了神经病史。已知或疑似存在脑形态学异常的个体被排除在研究之外。使用zung 自评焦虑量表（SAS）和zung 自评抑郁量表（SDS）来检测抑郁和情绪障碍。通过基于体素的分析以及对46个预定义的皮质和皮质下区域进行基于感兴趣区（VOI）的分析，对灌注进行自动定量。将两组的结果与参考模板进行比较。
在基于体素的分析中，患者和对照组在灌注缺损平均体积低于正常值2个标准差方面存在显著差异（21.8 ml 对10.4 ml；P = 0.02）。然而，研究组患者和对照组之间的高灌注区域没有显著差异。观察到灌注缺损与自身免疫性甲状腺炎诊断后的时间存在显著相关性（r = 0.42）。在基于VOI 的分析中，与对照组相比，研究组中的异常区域更为常见（P < 0.01）。然而，没有明显的地形模式。关于神经学检查结果，研究组患者和对照组之间未发现显著差异。然而，两组之间的SAS 和SDS 评分存在显著差异，但在我们的研究组中，这两个评分与灌注异常之间既无相关性，也与抑郁无关。
自身免疫性甲状腺炎患者脑灌注受损的这些发现进一步强化了个别病例中自身免疫性甲状腺炎可能累及大脑的假说。脑灌注不足的存在表明脑血管炎是最可能的发病机制模型。
