Department of Neurology, Memorial Hermann Hospital, University of Texas Health Science Center at Houston, 6410 Fannin St, Ste 1014, Houston, TX, 77030, USA.
Department of Pediatrics, Child Neurology, University of Texas Health Science Center at Houston, Houston, USA.
J Med Case Rep. 2022 Feb 20;16(1):74. doi: 10.1186/s13256-022-03299-6.
Mild encephalitis/encephalopathy with reversible splenial lesion is a clinical-radiological entity found to occur in the setting of an acute systemic inflammatory state with isolated lesions of the splenium of the corpus callosum and mild encephalopathy. Mild encephalitis/encephalopathy with reversible splenial lesion is commonly found to occur in children in the setting of viral infections. It has rarely been associated with Mycoplasma pneumoniae in the United States, unlike in Eastern and Southern Asia where this is much more prominent.
A 5-year-old African-American boy with autism spectrum disorder presented to our emergency department with acute onset intractable vomiting, diarrhea, and abnormal tensing movements for 2 days, following a 6-day period of fatigue, fever, and spastic abdominal pain. Emergent work-up in our department ruled out acute gastrointestinal pathologies. Given the high fevers and encephalopathy, there was concern for meningitis or encephalitis. His cerebrospinal fluid profile was concerning for viral meningitis, however extensive infectious workup was negative. Magnetic resonance imaging of his brain demonstrated a T2 fluid-attenuated inversion recovery sequence hyperintensity in the splenium of the corpus callosum, read as postictal changes by radiology. Continuous video electroencephalography demonstrated mild diffuse encephalopathy without electrographic correlate of his tensing episodes. He was determined to have mild encephalitis/encephalopathy with a reversible splenial lesion in the setting of a postinfectious etiology. He was treated with a single pulse-dose of intravenous methylprednisolone, following which he gradually returned to his baseline the next day. Repeat magnetic resonance imaging and cerebrospinal fluid evaluation demonstrated resolution of previous findings. He was ultimately diagnosed with an acute M. pneumoniae infection, which was determined to be the etiology of his mild encephalitis/encephalopathy with a reversible splenial lesion.
The presentation of mild encephalitis/encephalopathy with a reversible splenial lesion is often nonspecific, with behavioral symptoms ranging from irritability to disturbances in consciousness. Its prevalence is higher in the pediatric population, and is thought to be more of an infection-associated encephalopathy syndrome in this group. The infections are typically viral, more so than bacterial. M. pneumoniae, a small, atypical bacterium lacking a peptidoglycan cell wall, is a common respiratory tract pathogen found in children. Despite infection being so rampant in the pediatric community, very few cases of M. pneumoniae-associated mild encephalitis/encephalopathy with a reversible splenial lesion in the United States have been reported. In Eastern and Southern Asian countries, however, M. pneumoniae-associated mild encephalitis/encephalopathy with a reversible splenial lesion is much more commonly reported. This difference may potentially lie in the prevalence of macrolide-resistant M. pneumoniae, which is significantly higher in Asian countries given more liberal antibiotic use in M. pneumoniae infections. Infections with macrolide-resistant M. pneumoniae are reportedly greater in severity and duration. This amplified state may suggest a correlation between intensity of inflammatory response and the development of mild encephalitis/encephalopathy with a reversible splenial lesion. Given the rarity of M. pneumoniae-associated mild encephalitis/encephalopathy with a reversible splenial lesion in the United States, much remains unknown regarding predilection and optimum treatment strategy. As rates of macrolide-resistant M. pneumoniae begin to rise in the United States, maintaining a high level of suspicion remains key in better understanding this unique phenomenon.
轻度脑炎/脑病伴可逆胼胝体压部病变是一种临床-放射学实体，在急性全身性炎症状态下发生，表现为孤立的胼胝体压部病变和轻度脑病。轻度脑炎/脑病伴可逆胼胝体压部病变常见于病毒性感染儿童。在美国，与东亚和南亚不同，它很少与肺炎支原体有关，在东亚和南亚，这种情况更为突出。
一名 5 岁的非裔美国男孩患有自闭症谱系障碍，因急性难治性呕吐、腹泻和异常紧张性运动就诊，此前他经历了 6 天的疲劳、发热和痉挛性腹痛。在我院进行的紧急检查排除了急性胃肠道疾病。鉴于高热和脑病，人们担心是脑膜炎或脑炎。他的脑脊液特征提示病毒性脑膜炎，但广泛的感染性检查结果为阴性。他的大脑磁共振成像显示胼胝体压部 T2 液体衰减反转恢复序列高信号，放射科认为是癫痫后改变。连续视频脑电图显示轻度弥漫性脑病，与他紧张发作无电生理相关性。他被诊断为轻度脑炎/脑病伴胼胝体压部可逆病变，病因是感染后。他接受了单次静脉注射甲基强的松龙治疗，随后第二天逐渐恢复到基线水平。重复磁共振成像和脑脊液评估显示先前发现的病变已消退。最终他被诊断为急性肺炎支原体感染，这被认为是他轻度脑炎/脑病伴胼胝体压部可逆病变的病因。
轻度脑炎/脑病伴可逆胼胝体压部病变的表现通常是非特异性的，行为症状从易怒到意识障碍不等。它在儿科人群中的发病率较高，在该人群中被认为是一种更常见的感染相关脑病综合征。感染通常是病毒性的，比细菌性的更常见。肺炎支原体是一种缺乏肽聚糖细胞壁的小而非典型细菌，是儿童呼吸道常见病原体。尽管儿童社区中感染非常普遍，但在美国报告的肺炎支原体相关轻度脑炎/脑病伴可逆胼胝体压部病变的病例非常少。然而，在东亚和南亚国家，肺炎支原体相关轻度脑炎/脑病伴可逆胼胝体压部病变的报告更为常见。这种差异可能潜在地与大环内酯类耐药肺炎支原体的流行率有关，鉴于大环内酯类药物在肺炎支原体感染中的广泛应用，亚洲国家的耐药率明显更高。据报道，大环内酯类耐药肺炎支原体感染的严重程度和持续时间更长。这种放大状态可能表明炎症反应的强度与轻度脑炎/脑病伴可逆胼胝体压部病变的发展之间存在相关性。鉴于美国肺炎支原体相关轻度脑炎/脑病伴可逆胼胝体压部病变的罕见性，关于易感性和最佳治疗策略的了解仍然有限。随着美国大环内酯类耐药肺炎支原体的发病率开始上升，保持高度警惕仍然是更好地理解这一独特现象的关键。
