·臨床醫(yī)學(xué)圖像·

Wernicke腦病

圖1 女性患者，27歲，因頭暈、行走不穩(wěn)7 d并進行性加重，嗜睡2 d入院。既往有糖尿病病史，近2個月減肥，嚴(yán)格控制飲食攝入量（150 g/d）。體格檢查雙眼內(nèi)收和外展功能不良，左右視和上視可見眼震，雙側(cè)跟?膝?脛試驗欠穩(wěn)準(zhǔn)。臨床診斷為Wernicke腦病。頭部MRI檢查所見1a 橫斷面FLAIR成像顯示，第四腦室周圍異常高信號影，強度均勻（箭頭所示） 1b 橫斷面FLAIR成像顯示，中腦導(dǎo)水管周圍、四疊體、雙側(cè)乳頭體和灰結(jié)節(jié)異常高信號影（箭頭所示）1c 橫斷面FALIR成像顯示，第三腦室周圍異常高信號影（箭頭所示） 1d 橫斷面DWI（圖1b相同層面）顯示，病變呈明顯高信號（箭頭所示） 1e 通過乳頭體的冠狀位T1WI顯示，第三腦室旁異常低信號影，強度均勻（箭頭所示）；雙側(cè)乳頭體未見明顯萎縮Figure 1 A 27?year?old female patient suffered from progressive dizziness and walking unstable for 7 d and drowsiness for 2 d.Past medical history:diabetes.She had been on her special diet(principal food intake 150 g/d)to lose weight for 2 months.Physical examination showed bilateral ocular palsy,nystagmus in the side view(left and right)and front view.She could not complete both heel?knee?tibia test correctly and stalely.She was clinically diagnosed as having Wernicke's encephalopathy.Axial FLAIR image through pons revealed an abnormal heterogeneous hyperintensity mainly located at the tegmental part of pons around the forth ventricle(arrow indicates,Panel 1a).Axial FLAIR image through midbrain showed multiple heterogeneous hyperintensity lesions distributed symmetrically on the left and right sides located at periaqueductal area,corpus quadrigemina,bilateral mammillary bodies and tuberculum cinereum(arrow indicates,Panel 1b).Axial FLAIR image through thalamus showed abnormal hyperintensity located around the third ventricle(arrow indicates,Panel 1c).Axial DWI located at the same level as 1b revealed abnormal hyperintensity lesions(arrow indicates,Panel 1d).Coronal T1WI through mammillary body showed markedly heterogeneous slightly hypointensity in bilateral wall of the third ventricle(arrow indicates).There was no significant atrophy of bilateral mammillary bodies(Panel 1e).

Wernicke腦病是維生素B1缺乏導(dǎo)致的代謝性腦病，1881年由Wernicke首先描述，1940年Campbell和Russell提出其誘因是維生素B1缺乏。該病系維生素B1缺乏致特定區(qū)域神經(jīng)細(xì)胞能量代謝障礙所致，呈急性或亞急性起病，臨床主要表現(xiàn)為眼外肌癱瘓、共濟失調(diào)和意識障礙，最常見于慢性酒精中毒和妊娠性嘔吐；非維生素B1缺乏性Wernicke腦病系轉(zhuǎn)酮醇酶（TK）基因缺陷所致。MRI對早期診斷和疾病分期有重要價值，是首選影像學(xué)方法。典型特征為特定部位出現(xiàn)特定分布的病變，特定部位包括第四腦室旁（腦區(qū)被蓋和中腦頂蓋，圖1a）、中腦導(dǎo)水管周圍、乳頭體、四疊體（圖1b）、第三腦室側(cè)壁（丘腦內(nèi)側(cè)，圖1c），其中乳頭體最易受累，也可發(fā)生于延髓、小腦齒狀核、紅核、中腦頂蓋、尾狀核和大腦皮質(zhì)等少見部位；特定分布指病變分布呈對稱性。急性期，病變區(qū)神經(jīng)細(xì)胞可見細(xì)胞毒性水腫和血管源性水腫伴神經(jīng)膠質(zhì)和巨噬細(xì)胞增生，T2WI、FLAIR成像（圖1a～1c）和DWI（圖1d）呈高信號，T1WI呈稍低信號（圖1e）；亞急性期，以血管源性水腫為主，腦室旁白質(zhì)可見缺血性脫髓鞘改變，腦干長T2信號與神經(jīng)纖維網(wǎng)絡(luò)海綿樣變性相關(guān)，隨著病情進展，血?腦屏障破壞、血管外膜損害，增強掃描病變呈明顯強化，治療后MRI異常信號和強化可以逆轉(zhuǎn)甚至消失；慢性期，隨著神經(jīng)細(xì)胞缺失，上述病變范圍縮小，乳頭體和中腦頂蓋可見萎縮性改變，相鄰第三和第四腦室擴大。應(yīng)注意與多發(fā)性硬化、視神經(jīng)脊髓炎譜系疾病，病毒性腦炎累及腦干、腦血管病等相鑒別。

（天津市環(huán)湖醫(yī)院神經(jīng)放射科韓彤供稿）

Wernicke's encephalopathy

HAN Tong
Department of Neuroradiology,Tianjin Huanhu Hospital,Tianjin 300350,China(Email:mrbold@163.com)

10.3969/j.issn.1672?6731.2017.09.015