渗透性脱髓鞘综合征的临床和影像学研究（附四例报道）

Clinical and neuroimaging features of osmotic demyelination syndrome

目的 探讨渗透性脱髓鞘综合征的临床和神经影像特点.方法 对4例渗透性脱髓鞘综合征患者的临床演变过程、CSF、头颅CT和MRI、EEG动态变化特点、治疗及预后进行分析.结果 4例患者均存在低钠血症,纠正后出现精神意识改变、构音和吞咽困难、四肢瘫痪、肌张力障碍等症状,临床过程有双相性.EEG出现一过性的重度异常.头颅CT及CSF均未见异常.MRI特征性影像晚于临床表现10 d以后出现,4例患者首次MRI均为阴性,7～13 d后复查才显示病灶.MRI示4例患者均存在脑桥外髓鞘溶解症病灶,T1WI加权低信号,T2WI加权高信号,对称性地累及双侧尾状核、豆状核、丘脑、脑岛叶皮质、海马头部等部位,其中3例同时存在脑桥中央髓鞘溶解症改变,呈脑桥基底部位对称性T1低、T2高信号的蝶形病灶;Flair加权异常信号更清楚.3例有好转或痊愈,其中1例遗留明显肌张力障碍.结论 渗透性脱髓鞘综合征与慢性低钠血症有关,合并低血钾、低血氯时可能更易发生.治疗时应尽量避免过快纠正,临床病程具有双相性.MRI的特征性改变出现较迟,复查MRI是非常必要的.

Objective To investigate the clinical features and neuroimaging features of patients with osmotic demyelination syndrome （ODS）.Methods The clinical features and examination results ,including the clinical manifestations,the data of cranial MRI/CT,changes of EEG,treatment and prognosis,were analyzed in 4 patients with ODS.Results All the 4 patients had the history of hyponatraemia.The common clinical manifestations included psychiatric disorder,altered consciousness,dysphasia,dysphagia,quadriplegia and dystonia.Severe transient abnormal EEG was found in these patients,and all the brain CT scanning and CSF were negative.MRI features could only be noted 10 d after the appearing of clinical manifestations and all the first time MRI was negative in these 4 patients.Four patients were diagnosed as having extrapontine myelinolysis,showing symmetrical low T1-weighted signal and high T2-weighted signal within the pons,the basal ganglia,the thalami,the insular cortex and the hippocampal head.Three patients were also diagnosed as having central pontine myelinolysis,showing symmetrical T1 low signal and T2 high signal in the basilar part of pons; much clear imaging could be noted with the help of weighing the abnormal signals.Three patients got improvement with 1 having dystonia sequel.Conclusion ODS is correlated with chronic hyponatraemia,and both hypokalaemia and hypochloremia may be the 2 possible triggers; when they appear,quick correction is not needed.MRI features may be significantly delayed,thus,repeated imaging study is necessary.