Parsons Angela M, Grill Marie F, Feyissa Anteneh M, Britton Jeffrey, Hocker Sara, Crepeau Amy
Department of Neurology, Mayo Clinic, Scottsdale, Arizona, U.S.A.
Department of Neurology, Mayo Clinic, Jacksonville, Florida, U.S.A.
J Clin Neurophysiol. 2019 Mar;36(2):135-140. doi: 10.1097/WNP.0000000000000558.
Neuroinvasive West Nile virus (WNV) is rare, occurring in less than 1% of those infected, and may manifest as meningitis, encephalitis, and/or acute flaccid paralysis. Patients may present initially with nonspecific symptoms including fevers. Although rare, neuroinvasive WNV is associated with significant morbidity and mortality. The mainstay of treatment is supportive care. Electroencephalography (EEG) allows for identification of nonconvulsive status epilepticus and other epileptiform and nonepileptiform patterns suggestive of underlying cognitive dysfunction. Our aim was to describe specific EEG patterns observed in WNV neuroinvasive disease.
A retrospective chart review was conducted. West Nile virus was confirmed with serum and/or cerebrospinal fluid markers. Patients with a history of abnormal EEG were excluded. Electroencephalography reports were classified into categories based on the presence of epileptiform activity, focal slowing, generalized periodic discharges with triphasic morphology, and frontally predominant generalized rhythmic delta activity.
In our cohort of 34 patients, 60% of focal EEG abnormalities were anterior-predominant, seen as epileptiform discharges, focal slowing, or frontally predominant generalized rhythmic delta activity. Nonepileptiform EEG patterns included nonspecific slowing and generalized periodic discharges with triphasic morphology. Two patients had electrographic seizures, one arising from the frontocentral head region.
EEGs are important in the evaluation of WNV infection to rule out seizures or alternative causes of encephalopathy, and because of the risk of nonconvulsive seizures or status epilepticus in encephalitis. Although an anterior predominance of EEG abnormalities was seen in our cohort, this most likely is more correlative to encephalopathy than WNV itself. Although a specific correlative EEG pattern may not accompany all cases of WNV neuroinvasive disease, WNV should be considered as a possible etiology in patients presenting with an encephalitic or meningitic syndrome in the presence of abnormal EEG findings including encephalopathic patterns, particularly those with anterior predominant EEG changes.
西尼罗河病毒神经侵袭性疾病较为罕见，在不到1%的感染者中出现，可能表现为脑膜炎、脑炎和/或急性弛缓性麻痹。患者最初可能出现包括发热在内的非特异性症状。尽管罕见，但西尼罗河病毒神经侵袭性疾病与显著的发病率和死亡率相关。治疗的主要手段是支持性护理。脑电图（EEG）有助于识别非惊厥性癫痫持续状态以及其他提示潜在认知功能障碍的癫痫样和非癫痫样模式。我们的目的是描述西尼罗河病毒神经侵袭性疾病中观察到的特定脑电图模式。
进行了一项回顾性病历审查。通过血清和/或脑脊液标志物确诊西尼罗河病毒。排除有脑电图异常病史的患者。根据癫痫样活动、局灶性慢波、三相形态的广泛性周期性放电以及额叶为主的广泛性节律性δ活动的存在，将脑电图报告分类。
在我们的34例患者队列中，60%的脑电图局灶性异常以额叶前部为主，表现为癫痫样放电、局灶性慢波或额叶为主的广泛性节律性δ活动。非癫痫样脑电图模式包括非特异性慢波和三相形态的广泛性周期性放电。两名患者出现脑电图癫痫发作，其中一名起源于额中央头部区域。
脑电图在评估西尼罗河病毒感染以排除癫痫发作或脑病的其他原因方面很重要，并且由于脑炎中有非惊厥性癫痫发作或癫痫持续状态的风险。尽管在我们的队列中观察到脑电图异常以额叶前部为主，但这很可能与脑病的相关性比与西尼罗河病毒本身的相关性更大。尽管并非所有西尼罗河病毒神经侵袭性疾病病例都会伴有特定的相关脑电图模式，但在出现包括脑病模式在内的异常脑电图结果（特别是那些额叶脑电图改变为主的情况）的脑炎或脑膜炎综合征患者中，应将西尼罗河病毒视为可能的病因。
