Meningoencephaloradiculitis following infection with tick borne encephalitis virus: case report and review of the literature

Evaluating the need for standardised disease manifestation categories in patients infected with the tick-borne encephalitis virus: A Delphi panel

Categorization systems for tick-borne encephalitis virus (TBEV) infection lack consistency in classifying disease severity. To evaluate the need for a standard, consensus-based categorisation system for TBEV infection across subtypes, we gathered an expert panel of clinicians and scientists with diverse expertise in TBEV infection. Consensus was sought using the Delphi technique, which consisted of 2 web-based survey questionnaires and a final, virtual, consensus-building exercise. Ten panellists representing 8 European countries participated in the Delphi exercise, with specialities in neurology, infectious disease, paediatrics, immunology, virology, and epidemiology. Panellists reached unanimous consensus on the need for a standardised, international categorisation system to capture both clinical presentation and severity of TBEV infection. Ideally, such a system should be feasible for use at bedside, be clear and easy to understand, and capture both the acute and follow-up phases of TBEV infection. Areas requiring further discussion were (1) the timepoints at which assessments should be made and (2) whether there should be a separate system for children. This Delphi panel study found that a critical gap persists in the absence of a feasible and practical classification system for TBEV infection. Specifically, the findings of our Delphi exercise highlight the need for the development of a user-friendly classification system that captures the acute and follow-up (i.e., outcome) phases of TBEV infection and optimally reflects both clinical presentation and severity. Development of a clinical categorisation system will enhance patient care and foster comparability among studies, thereby supporting treatment development, refining vaccine strategies, and fortifying public health surveillance.

Clinical manifestations and outcomes of Tick-borne encephalitis: A systematic literature review

Tick-borne encephalitis (TBE) is caused by a viral infection and can lead to acute and persistent damage to the central and peripheral nervous systems. Recently, the incidence of TBE in Europe has risen, and epidemiological patterns of disease have changed, emphasising the need for improved understanding of this vaccine-preventable disease. Although TBE is endemic in many countries, the disease spectrum of TBE is not well described. We sought to characterise the clinical manifestations and outcomes of TBE by estimating the proportions of TBE patients with each type of manifestation and the risk of adverse outcomes for children and adults separately. A systematic literature review was conducted on 2 August 2022 for articles published in any language since 1 January 2007. Additional relevant studies were found in reference lists of identified articles. The review was limited to countries where only the European subtype of TBEV circulates. Of the 1,632 unique titles and abstracts identified and reviewed, 21 were retained for data analysis. The 21 studies were split into a main analysis (15 studies reporting patients hospitalised with laboratory-confirmed TBE) and a secondary analysis (6 studies reporting hospitalised and non-hospitalised patients who sought medical treatment for laboratory-confirmed TBE). The main analysis included 5,012 adults and 640 children. The predominant clinical manifestation in adults was encephalitis (61 %), followed by meningitis (33 %), radiculitis (14 %), and myelitis (6 %) (the manifestations were evaluated independently, so they will not sum to 100 %). With outliers removed, similar proportions of adults had encephalitis (48 %) and meningitis (44 %). Among cases in children, meningitis (77 %) was the most common manifestation, whereas encephalitis (23 %) and myelitis (1.3 %) were less frequent. Among hospitalised patients with TBE, the proportion of intensive care unit (ICU) admissions and deaths were similar for adults (15.5 % and 0.9 %, respectively) and children (16.4 % and 0 %, respectively.) The percentage of patients with sequelae when examined >12 months from acute TBE was 39.5 % for adults and 16.2 % for children. The evidence was challenging to aggregate due to study heterogeneity, variability in categorising clinical manifestations of central nervous system disease, variability of denominator populations, and differences in healthcare systems and diagnostic practices across countries. Our study disclosed distinct patterns of clinical manifestation among hospitalised adult and child patients with TBE and a high proportion of ICU admissions and long-term neurological sequelae across both age groups. These findings reinforce the continued need for preventive measures in the populations at risk. Moreover, variability of study admission criteria, including difficulty with clinical manifestation categorisation, calls for a more standardised approach to summarising TBE manifestations and outcomes across Europe.

A comprehensive neurological perspective on tick-borne flaviviruses, with emphasis on Powassan virus

Powassan virus (POWV), a tick-borne flavivirus transmitted primarily by Ixodes ticks, poses a significant threat as it can lead to severe neuroinvasive illness. This review delves into the nuanced clinical presentation of Powassan infection, a challenge in diagnosis exacerbated by the absence of an available vaccine. Over the past decade, the prevalence of POWV has surged in North America, necessitating a thorough examination of its neurological manifestations alongside tick-borne encephalitis virus (TBEV). A comprehensive literature search conducted up to January 2024 revealed 135 cases of neurological symptoms associated with either Powassan or TBEV infection. Notably, severe occipital headache emerged as the most prevalent symptom (22.75%), followed by meningoencephalitis (10.34%), seizures (8.27%), and flaccid paresis (6.8%). Additional manifestations included poor balance, wide gait, dysarthria, facial nerve palsy, seizure, slurred speech, and absent deep tendon reflexes. Tragically, nine cases resulted in fatal outcomes attributed to POWV infection. This analysis highlights the intricate spectrum of neurological symptoms associated with Powassan infection and underscores the necessity for heightened awareness among medical practitioners, particularly in regions with a higher prevalence of the virus. The complexity of symptoms emphasizes the need for further research to unravel the factors contributing to this diversity. Additionally, exploring potential treatment avenues and vaccine development is crucial in addressing the rising threat posed by POWV, ultimately enhancing our ability to manage and prevent severe neurological outcomes.