Department of Neurology, North Karelia Central Hospital, Joensuu, Finland; Clinical Neurosciences, University of Turku, Turku, Finland.
Neuroepidemiology. 2024;58(4):276-283. doi: 10.1159/000538020. Epub 2024 Feb 28.
The epidemiology of encephalitis varies by region and time. Available Finnish data are outdated and there are no data from eastern parts of the country nor concerning the occurrence of autoimmune encephalitides.
Patients with encephalitis were identified from mandatory administrative registries in North Karelia Central Hospital. The diagnoses were verified and data extracted by reviewing the patient records. Study period was 2010-2021. Only patients >16 years of age were included.
Fifty-one patients with a clinical encephalitis were identified (55% men) with a median age of 65 years (interquartile range 45, 73; total age range 16-88 years) indicating a crude incidence of 3.1/100,000 person-years for the entire study period. A specific aetiology could be identified in 31 cases (61%) with tick-borne encephalitis (TBE) being the most common one (20% of all 51 cases), followed by herpes simplex virus type 1 (HSV-1, 16%) and varicella zoster virus (VZV, 14%). Autoimmune aetiology was confirmed in 10%. TBE was most often found in the youngest age group (16-52 years of age) and the herpes viruses in the oldest group (71 years or older). A specific cause was most often identified in the oldest patients (78%). TBE patients were younger than patients with VZV (p = 0.0009) or HSV-1 (p = 0.0057), but there was no difference when they were compared to patients with autoimmune (p = 0.27) or unknown (p = 0.074) aetiology. At presentation, there were differences in the occurrence of some clinical signs and symptoms between aetiologies but nothing specific. Eight patients (16%) were immunosuppressed. Inpatient seizures occurred in 10 patients (20%). In these cases, the aetiology was HSV-1 in 50% and TBE or VZV in none. A full recovery was observed in 51% of all patients while 3 patients (6%) had died of the encephalitis while in hospital or shortly after discharge.
Adult-onset encephalitis was more common and the patients older in easternmost Finland than previously reported in other parts of the country. TBE, HSV-1, and VZV are the most commonly identified specific aetiologies whereas a fifth of the cases are probably caused by autoimmunity. Prognosis depended on aetiology but was very good in the majority of cases.
脑炎的流行病学因地区和时间而异。芬兰现有的数据已经过时，而且没有来自该国东部地区的数据，也没有关于自身免疫性脑炎发生的数据。
在北卡累利阿中央医院，通过强制性行政登记册确定患有脑炎的患者。通过回顾病历来验证和提取诊断数据。研究时间为 2010 年至 2021 年。仅纳入年龄>16 岁的患者。
共确定了 51 例有临床症状的脑炎患者（55%为男性），中位年龄为 65 岁（四分位距 45，73；总年龄范围 16-88 岁），表明整个研究期间的粗发病率为 3.1/100,000 人年。在 31 例（61%）中可以明确病因，其中蜱传脑炎（TBE）最常见（51 例中的 20%），其次是单纯疱疹病毒 1 型（HSV-1，16%）和水痘带状疱疹病毒（VZV，14%）。确诊自身免疫病因的有 10%。TBE 最常发生在最年轻的年龄组（16-52 岁），而疱疹病毒最常发生在最年长的年龄组（71 岁或以上）。最年长的患者通常能明确病因（78%）。TBE 患者比 VZV（p=0.0009）或 HSV-1（p=0.0057）患者年轻，但与自身免疫（p=0.27）或不明病因（p=0.074）患者相比，差异无统计学意义。在就诊时，不同病因之间存在一些临床体征和症状的差异，但没有特异性。8 名患者（16%）存在免疫抑制。10 名患者（20%）在住院期间出现癫痫发作。在这些情况下，病因在 50%为 HSV-1，而 TBE 或 VZV 则没有。所有患者中 51%完全康复，3 名患者（6%）因脑炎在住院或出院后不久死亡。
在芬兰最东部，成人发病的脑炎比该国其他地区以前报告的更为常见，患者年龄也更大。TBE、HSV-1 和 VZV 是最常见的明确病因，而五分之一的病例可能由自身免疫引起。预后取决于病因，但大多数情况下预后良好。
