MRI and planimetric CT follow-up study of patients with severe tick-borne encephalitis

Magnetic resonance imaging in acute meningoencephalitis of viral and unknown origin: frequent findings and prognostic potential

Background

Magnetic resonance imaging (MRI) findings in meningoencephalitis have mainly been described in terms of their diagnostic value rather than their prognostic potential, except for herpes simplex virus (HSV) encephalitis. The aims of our study were to describe frequency and anatomic locations of MRI abnormalities specific to limbic, circadian and motor systems in a cohort of meningoencephalitis patients, as well as to investigate the prognostic value of these MRI findings.

Methods

A secondary, selective analysis of a retrospective database including all meningitis, meningoencephalitis and encephalitis cases treated between 2016 and 2018 in the University hospital of Bern, Switzerland was performed. Patients with meningitis of any cause, bacterial or autoimmune causes of encephalitis were excluded.

Results

MRI scans and clinical data from 129 meningoencephalitis cases found that the most frequent causes were tick-borne encephalitis (TBE, 42%), unknown pathogens (40%), VZV (7%), and HSV1 (5%). At discharge, median modified Rankin Score (mRS) was 3 (interquartile range, IQR, 1), 88% of patients had persisting signs and symptoms. After a median of 17 months, median Glasgow Outcome Score (GOS) was 5 (IQR 1), 39% of patients still had residual signs or symptoms. All patients with HSV, 27% with TBE and 31% of those with meningoencephalitis of unknown etiology had fluid-attenuated inversion recovery (FLAIR) and to a lesser extent diffusion-weighted imaging (DWI) lesions in their initial MRI, with highly overlapping anatomical distribution. In one fifth of TBE patients the limbic system was affected. Worse outcome was associated with presence of DWI and/or FLAIR lesions and lower normalized apparent diffusion coefficient (ADC) signal intensities.

Conclusion

Presence of FLAIR lesions, restricted diffusion as well as the extent of ADC hypointensity in initial MRI are parameters which might be of prognostic value regarding the longterm clinical outcome for patients with meningoencephalitis of viral and of unknown origin. Although not described before, affection of limbic structures by TBE is possible as shown by our results: A substantial proportion of our TBE patients had FLAIR signal abnormalities in these regions.

Tick-Borne Encephalitis (TBE): From Tick to Pathology

Tick-borne encephalitis (TBE) is a viral arthropod infection, endemic to large parts of Europe and Asia, and is characterised by neurological involvement, which can range from mild to severe, and in 33-60% of cases, it leads to a post-encephalitis syndrome and long-term morbidity. While TBE virus, now identified as Orthoflavivirus encephalitidis, was originally isolated in 1937, the pathogenesis of TBE is not fully appreciated with the mode of transmission (blood, tick, alimentary), viral strain, host immune response, and age, likely helping to shape the disease phenotype that we explore in this review. Importantly, the incidence of TBE is increasing, and due to global warming, its epidemiology is evolving, with new foci of transmission reported across Europe and in the UK. As such, a better understanding of the symptomatology, diagnostics, treatment, and prevention of TBE is required to inform healthcare professionals going forward, which this review addresses in detail. To this end, the need for robust national surveillance data and randomised control trial data regarding the use of various antivirals (e.g., Galidesivir and 7-deaza-2'-CMA), monoclonal antibodies, and glucocorticoids is required to improve the management and outcomes of TBE.

Assessment of the YKL-40 concentration in patients with tick-borne encephalitis

Tick-borne encephalitis (TBE) is a viral infection of the central nervous system (CNS) caused by tick-borne encephalitis virus (TBEV). It might take several clinical courses such as: meningitis, meningoencephalitis or meningoencephalomyelitis. The aim this study was to compare the YKL-40 concentration in cerebrospinal fluid (CSF) of patients with different clinical presentations of TBE and patients with excluded meningitis (control group). The concentration of YKL-40 in CSF was determined using Fujirebio tests (Ghent, Belgium) in 32 patients with TBE: Group I-patients with meningoencephalitis (n = 16); Group II-patients with meningitis (n = 16). The control group (CG) consisted of 17 patients in whom any inflammatory process in central nervous system was excluded. The concentration of YKL-40 was significantly higher in encephalitis group than in the CG after 7 days from the last dose of treatment. The concentration in patients with neuroinflammation had a significantly different concentration of YKL-40 compared to patients from the neuroinflammation control group. The ROC curve analysis indicates that CSF YKL-40 concentration at cut-off 783.87 differentiated TBE patients from CG with 100% specificity and 70% sensitivity and CSF YKL-40 concentration at cut-off 980.11 differentiated meningitis from meningoencephalitis with 87.5% specificity and 62.5% sensitivity. YKL-40 takes part in TBE pathogenesis, its concentration is the highest at the early stage of CNS involvement and decreases in the convalescent period. As YKL-40 was significantly higher in the meningitis than in the meningoencephalitis group, it might be used as biomarker in differentiation of these clinical forms of TBE.

Analysis of the Interventions of Medical Emergency Teams in Older Patients in Selected Polish Cities with County Status: A Retrospective Cohort Study

Introduction: Geriatric patients account for a large proportion of interventions of medical emergency teams (METs). The aim of this study was to analyse medical emergency interventions in the Biała Podlaska and Chełm (Poland) between 2016 and 2018 in a group of patients ≥ 65 years of age. Materials and Methods: We analysed medical records of 1200 older patients treated by METs in Biała Podlaska and Chełm (Lublin Province, Poland). The research was conducted from June 2019 to March 2020 at the Emergency Medical Service Station in Biała Podlaska and the Medical Rescue Station in Chełm (Independent Public Complex of Health Care Facilities). Results: A total of 92.5% of medical emergency service interventions took place at the patient’s home. The mean time of stay at the scene was 20 min. The highest number of interventions occurred between 8:00 p.m. and 8:59 p.m. There were no statistically significant differences in the type of ambulance used depending on the patient’s sex, while there was a statistically significant relationship between priority code and sex. Cardiovascular diseases were diagnosed in 40% of patients, and the symptoms were not precisely classified in almost the same percentage of patients. Mortality cases accounted for 3.1% of the 1200 interventions analysed. Ambulance dispatch resulted in the patient being transported to the hospital emergency department in 69.1% of cases. Conclusions: METs were called for a variety of diseases due to the fact that geriatric patients are not able to distinguish a life-threatening condition. Medical procedures performed by METs from Biała Podlaska and Chełm were closely related to the initial diagnoses made by these teams. It was irrelevant whether a specialist or non-specialist medical emergency service was used. Paramedics are very well trained to practice their profession and are able to provide treatment to older patients in a state of sudden life threat.

Proton magnetic resonance spectroscopy (1H-MRS) of the brain in patients with tick-borne encephalitis

Tick-borne encephalitis (TBE) is a disease caused by a tick-borne encephalitis virus (TBEV) belonging to the Flaviviridae family. The aforementioned virus is transmitted by the bite of infected ticks. In the recent years, TBEV has become a serious public health problem with a steady increase in its incidence, mainly due to the climate changes and spreading the infected ticks into new territories. The standard protocol of TBE diagnosis involves the serological laboratory test with a minor role of imaging techniques such as magnetic resonance imaging. Long-term complications affecting patients daily activities are reported in about 40–50% of the cases. However, no changes are revealed in the laboratory tests or the imaging examination. The development of new imaging techniques such as proton magnetic resonance spectroscopy (¹H-MRS) can broaden the knowledge about TBE, contributing to its prevention. The aim of this study was to assess the usefulness of ¹H-MRS of the brain in patients with TBE. Compared to controls, a statistically significant decrease in the N-acetylaspartate /creatine ratio was found bilaterally in the right and left thalamus as well as a statistically significant increase in the choline/creatine ratio in the right and left thalamus.

Assessment of the tau protein concentration in patients with tick-borne encephalitis

There have been suggestions that tick-borne encephalitis (TBE) may cause neurodenenerative changes in the brain. The aim of this study was the assessment of the tau protein concentration in cerebrospinal fluid (CSF) of patients with different clinical forms of TBE. The concentration of tau protein in CSF was determined using Fujirebio tests (Ghent, Belgium) in 35 patients with TBE: group I-patients with meningitis (n = 16); group II-patients with meningoencephalitis (n = 19). None of the patients reported any neurodegenerative disorder that could affect the results of the study. The control group (CG) consisted of 10 patients in whom inflammatory process in central nervous system was excluded. Tau protein concentration in CSF before treatment did not differ significantly between the examined groups, while its concentration was significantly higher in encephalitis group than in CG after 14 days of treatment. Significant increase in tau protein concentration after treatment was observed in both examined groups. The comparison between the group of patients who fully recovered and patients who presented with persistent symptoms on discharge showed significant differences in tau protein concentration before and after treatment. ROC curve analysis indicates that CSF tau protein concentration before treatment may predict complicated course of the disease with 90.9% specificity and 80% sensitivity, while after treatment, specificity became 72.7% and 71.4% for sensitivity. Correlation analysis showed that in TBE patients (both meningoencephalitis and meningitis groups), CSF pleocytosis before treatment correlated negatively with tau protein concentration in CSF. (1) Neurodegeneration process is present in TBE encephalitis. (2) Tau protein concentration may be used as a predictor of complicated course of TBE.

Evaluation of NSE and S100B in patients with tick-borne encephalitis

INTRODUCTION

The aim of this study was the assessment of neuron-specific enolase (NSE) and S-100 concentration in serum and cerebrospinal fluid (CSF) in patients with different clinical forms of tick-borne encephalitis (TBE).

MATERIAL AND METHODS

The serum and CFS concentrations of S100B and NSE of 43 patients with TBE were measured with ELISA method using commercial kits: NSE and S100B Elisa Kit (DRG, Germany). Subjects were divided into: Group I-patients with meningoencephalitis (n = 17) and Group II-patients with meningitis (n = 26). None of the patients reported any neurodegenerative disorder that could affect the results of the study. The control group (CG) consisted of 13 patients. These patients were admitted to the hospital because of headache, and the CSF examination excluded inflammatory process. Samples were collected on admission (sample 1) and after treatment (sample 2).

RESULTS

Neuron-specific enolase concentration in CSF was higher in group I than in group II (p = 0.0002) and controls (p = 0.04). NSE concentration was higher in the second serum and CSF sample in both groups. S100B concentration did not differ between TBE patients and controls. NSE concentration in serum after 14 days was higher in the sequelae group (34.3 ± 9.7 vs. 16.7 ± 15, p = 0.04). Also, NSE serum sample 2/serum sample 1 ratio was significantly higher in the sequelae group (3.57 ± 0.92 vs. 1.53 ± 1.99, p = 0.04). Receiver Operating Characteristic curve analysis indicated that NSE concentration in serum II differentiates sequelae group from other meningoencephalitis patients (p = 0.0001). S100B serum sample 2/CSF sample 2 ratio was lower in the sequelae group (0.05 ± 0.1 vs. 0.37 ± 0.28, p = 0.02).

CONCLUSIONS

(a) Neurodegeneration process is present in TBE encephalitis. (b) NSE concentration correlates with inflammatory parameters in CSF in TBE. (c) Neurodegeneration is present even after clinical recovery of TBE. (d) NSE could be used in the prediction of TBE course. (e) S-100 did not differ between TBE patients and controls.

Epidemiological patterns of tick-borne encephalitis in Lithuania and clinical features in adults in the light of the high incidence in recent years: a retrospective study

Background and purpose

Lithuania is one of the countries with the highest incidence of tick‐borne encephalitis (TBE) in Europe. The aim of this study was to describe the epidemiological patterns of TBE in Lithuania, and characterize clinical features in adults in the light of the high incidence in recent years.

Methods

Surveillance data available on the website of the Centre for Communicable Diseases and AIDS of Lithuania were used to describe the epidemiological patterns of TBE. The retrospective study included 712 patients hospitalized in the Centre for Infectious Diseases and the Centre for Neurology of Vilnius University in the years 2005–2014.

Results

Tick‐borne encephalitis incidence rates have been increasing by 8.5% per year for the 45‐year period from 1970 to 2014. The joinpoint model finds two joinpoints at 1991 and 1994, with a significant decrease of 8.4% per year (P < 0.05) prior to the joinpoint at 1991, and a rise of 195.2% afterwards. TBE presented with meningoencephalitis in 556 cases (81.3%). A total of 129 patients (18%) had a severe case of the disease. The most common neurological signs were ataxia (579, 81.3%), meningeal signs (474, 66.5%) and tremor (338, 47.5%). Limb paresis was observed in 6.3% of patients. Five patients (0.7%) died, and 544 patients (76.7%) were discharged with sequelae.

Conclusions

Intensified efforts in promoting TBE vaccination will be needed in the light of the high incidence and expanded spatial distribution. Significant prognostic factors for severe cases of the disease were age above 61 and delayed immune response of specific immunoglobulin G.