Kumar Rashmi
Department of Pediatrics, King George's Medical University, Lucknow, India.
F1000Res. 2020 Jan 29;9. doi: 10.12688/f1000research.20634.1. eCollection 2020.
Encephalitis is an important cause of morbidity, mortality, and permanent neurologic sequelae globally. Causes are diverse and include viral and non-viral infections of the brain as well as autoimmune processes. In the West, the autoimmune encephalitides are now more common than any single infectious cause, but, in Asia, infectious causes are still more common. In 2006, the World Health Organization coined the term "acute encephalitis syndrome", which simply means acute onset of fever with convulsions or altered consciousness or both. In 2013, the International Encephalitis Consortium set criteria for diagnosis of encephalitis on basis of clinical and laboratory features. The most important infectious cause in the West is herpes simplex virus, but globally Japanese encephalitis (JE) remains the single largest cause. Etiologic diagnosis is difficult because of the large number of agents that can cause encephalitis. Also, the responsible virus may be detectable only in the brain and is either absent or transiently found in blood or cerebrospinal fluid (CSF). Virological diagnosis is complex, expensive, and time-consuming. Different centres could make their own algorithms for investigation in accordance with the local etiologic scenarios. Magnetic resonance imaging (MRI) and electroencephalography are specific for few agents. Clinically, severity may vary widely. A severe case may manifest with fever, convulsions, coma, neurologic deficits, and death. Autoimmune encephalitis (AIE) includes two major categories: (i) classic paraneoplastic limbic encephalitis (LE) with autoantibodies against intracellular neuronal antigens (Eg: Hu and Ma2) and (ii) new-type AIE with autoantibodies to neuronal surface or synaptic antigens (Eg: anti-N-methyl-D-aspartate receptor). AIE has prominent psychiatric manifestations: psychosis, aggression, mutism, memory loss, euphoria, or fear. Seizures, cognitive decline, coma, and abnormal movements are common. Symptoms may fluctuate rapidly. Treatment is largely supportive. Specific treatment is available for herpesvirus group and non-viral infections. Various forms of immunotherapy are used for AIE.
在全球范围内，脑炎是导致发病、死亡和永久性神经后遗症的重要原因。其病因多种多样，包括脑部的病毒和非病毒感染以及自身免疫过程。在西方，自身免疫性脑炎现在比任何单一感染性病因都更为常见，但在亚洲，感染性病因仍然更为常见。2006年，世界卫生组织提出了“急性脑炎综合征”这一术语，其简单含义是伴有惊厥或意识改变或两者皆有的急性发热发作。2013年，国际脑炎联盟根据临床和实验室特征制定了脑炎诊断标准。西方最重要的感染性病因是单纯疱疹病毒，但在全球范围内，日本脑炎（JE）仍然是单一最大病因。由于可导致脑炎的病原体种类繁多，病因诊断较为困难。此外，致病病毒可能仅在脑部可检测到，在血液或脑脊液（CSF）中不存在或只是短暂出现。病毒学诊断复杂、昂贵且耗时。不同中心可根据当地病因情况制定各自的检查方案。磁共振成像（MRI）和脑电图对少数病原体具有特异性。临床上，严重程度差异很大。严重病例可能表现为发热、惊厥、昏迷、神经功能缺损和死亡。自身免疫性脑炎（AIE）包括两大类：（i）经典副肿瘤性边缘叶脑炎（LE），伴有针对细胞内神经元抗原的自身抗体（例如：Hu和Ma2），以及（ii）新型AIE，伴有针对神经元表面或突触抗原的自身抗体（例如：抗N-甲基-D-天冬氨酸受体）。AIE具有突出的精神症状表现：精神病、攻击行为、缄默症、记忆力减退、欣快感或恐惧。癫痫发作、认知功能下降、昏迷和异常运动很常见。症状可能迅速波动。治疗主要是支持性的。对于疱疹病毒组感染和非病毒感染有特效治疗方法。各种形式的免疫疗法用于治疗AIE。
