A 41-year-old man presented in May 2023 with a new-onset episode of generalised seizure and postictal confusion. He became restless and irritable at the emergency department, with nausea and vomiting. Over the previous 10 days, he had developed a fever and for 5 days had experienced new-onset intermittent headaches and fatigue. He had a history of hypertension but was otherwise well. On examination, he was febrile to 37.6℃ with mildly elevated blood pressure (144/80 mmHg) but normal oxygen saturation (96%). His Glasgow Coma Scale score was 11 (eye 3, verbal 3, motor 5). He was disorientated, unable to follow commands and spoke disorganised words. He could localise to noxious stimuli in all limbs. Muscle strength, tone and reflexes were normal throughout with flexor plantar responses. There was no neck stiffness or asterixis. Initial investigations showed leucocytosis of 18.7×109/L (4.0–11.0) with 83.3% neutrophils and elevated C reactive protein at 12.9 mg/L (<10) along with mildly elevated transaminases. He had severe hypokalaemia at 2.4 mmol/L (3.5–4.9) but no endocrine, urinary or coagulation abnormalities. Autoimmune serological screening was negative, and serology for HIV and syphilis was negative. CT scan of chest showed bilateral interstitial pneumonia (figure 1A). Contrast-enhancement MR scan of brain showed a dilated left lateral ventricle without parenchymal and leptomeningeal abnormalities (figure 1B–C). Continuous electroencephalogram (EEG) showed mid-amplitude theta slowing over the frontocentral and temporal region with a frontal dominance, suggesting encephalopathy (figure 1D). Figure 1 (A) CT scan of chest (non-contrast) showing bilateral interstitial pneumonia. (B, C) MR scan of brain T2/FLAIR (B) and T1 with gadolinium (C) showing a dilated left lateral ventricle but no other abnormalities. (D) A 24-hour continuous EEG recording identified mid-amplitude theta slowing over the frontocentral and temporal region with a frontal dominance. EEG, electroencephalogram. What is the differential diagnosis? The differential diagnosis is broad for a patient …

中文翻译：

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新发癫痫和急性脑病

一名 41 岁男性于 2023 年 5 月就诊，出现新发的全身性癫痫发作和发作后意识模糊。他在急诊室变得焦躁易怒，伴有恶心和呕吐。过去 10 天里，他发烧，并连续 5 天出现新发的间歇性头痛和疲劳。他有高血压病史，但其他方面状况良好。经检查，他发烧至37.6℃，血压轻度升高（144/80 mmHg），但血氧饱和度正常（96%）。他的格拉斯哥昏迷量表评分为 11（眼睛 3 分、语言 3 分、运动 5 分）。他迷失了方向，无法听从命令，说话也杂乱无章。他可以定位四肢的有害刺激。肌肉力量、张力和反射始终正常，足底屈肌反应也正常。没有颈部僵硬或扑翼样震颤。初步调查显示白细胞增多为 18.7×109/L (4.0–11.0)，中性粒细胞为 83.3%，C 反应蛋白升高为 12.9 mg/L (<10)，转氨酶轻度升高。他患有严重低钾血症，浓度为 2.4 mmol/L (3.5–4.9)，但没有内分泌、泌尿或凝血异常。自身免疫血清学筛查呈阴性，艾滋病毒和梅毒血清学呈阴性。胸部CT扫描显示双侧间质性肺炎（图1A）。大脑对比增强 MR 扫描显示左侧脑室扩张，无实质和软脑膜异常（图 1B-C）。连续脑电图 (EEG) 显示额中央和颞区中波幅 θ 减慢，以额叶为主，提示脑病（图 1D）。图 1 (A) 胸部 CT 扫描（非造影）显示双侧间质性肺炎。(B, C) 大脑 T2/FLAIR (B) 和钆 T1 的 MR 扫描 (C) 显示左侧侧脑室扩张，但没有其他异常。(D) 24 小时连续脑电图记录识别出额中央和颞区中波幅 theta 减慢，且以额叶为主。脑电图，脑电图。鉴别诊断是什么？对于患者来说，鉴别诊断很广泛……