Clinical characteristics and factors affecting disease severity in hospitalized tick-borne encephalitis patients in Norway from 2018 to 2022.

PURPOSE: To describe the clinical characteristics and factors associated with disease severity in a Norwegian cohort of hospitalized patients with tick-borne encephalitis (TBE). METHODS: This observational multicenter study included hospitalized patients with TBE in the endemic area in the southeastern region of Norway from 2018 to 2022. Clinical signs and findings from laboratory tests, EEG, CT and MRI scans were recorded. Patient characteristics were compared among those with mild, moderate, and severe TBE, and factors associated with disease severity were identified. RESULTS: Nearly all eligible patients were included in the final cohort (153/189 participants, 81%). The median age was 56 years, 63% were men, and 7% were vaccinated against TBE; no participants were fully vaccinated. TBE presented as mild (meningeal) disease in 31% of patients and as moderate or severe (encephalitic) disease in 54% and 14% of patients, respectively. We found that 46% of the patients had a monophasic course, 64% had hyponatremia, and 7% presented with central nervous system (CNS) symptoms without pleocytosis in cerebrospinal fluid (CSF). Dysesthesia, a symptom previously not described, was reported in 10% of the patients. Most objective findings were related to the CNS. Preexisting comorbidities, CRP and CSF protein levels were predictors of more severe disease. CONCLUSION: This novel presentation of a large Norwegian cohort supports TBE as a serious disease in the southeastern region of Norway. The majority of hospitalized patients presented with encephalitis, and fewer presented with meningitis. Comorbidities, CRP and CSF protein levels were associated with more severe disease. TRIAL REGISTRATION: Prosjekt #2,296,959 - The Norwegian Tick-borne Encephalitis Study - NOTES. Acute phase characteristics and long-term outcomes. - Cristin.

The first tigecycline resistant Enterococcus faecium in Norway was related to tigecycline exposure.

OBJECTIVES: We describe the first tigecycline resistant enterococcal isolate in Norway and the mechanisms involved. MATERIAL AND METHODS: The Norwegian National Advisory Unit on Detection of Antimicrobial Resistance (K-res). received in 2022 an Enterococcus faecium blood culture isolate with decreased susceptibility to tigecycline from a hospitalized patient in the South-Eastern Norway Health region for confirmatory testing. K-res verified a tigecycline-resistant E. faecium (TigR) with broth microdilution MIC of 0.5 mg/L. The patient had received treatment with tigecycline because of an infection with a linezolid- and vancomycin-resistant but tigecycline susceptible E. faecium (TigS) 47 days prior to the detection of the corresponding tigecycline-resistant isolate. Whole-genome comparisons, cgMLST and SNP analyses revealed that the two ST117 strains were closely related. RESULTS: The TigR isolate showed a novel deletion of 2 amino acids (K57Y58) in a polymorphic region of ribosomal protein S10 previously associated with tigecycline resistance and a deletion of the tet(M) leader peptide previously related to increased expression of tet(M) and tigecycline resistance in enterococci. CONCLUSIONS: Genomic and epidemiological analyses confirm that the two E. faecium (TigR and TigS) are closely related isolates of the same strain and that the two deletions (in rpsJ and of tet(M) leader peptide) account for the tigecycline resistance in TigR.

Drug-induced aseptic meningitis. / Legemiddelindusert aseptisk meningitt.

Drug-induced aseptic meningitis is a rare but serious condition that should be suspected in patients with meningitis who test negative for a microbiological agent. The medical history is presented here of a woman with recurrent urinary tract infections where meningitis symptoms arose after repeated exposure to a frequently prescribed drug.

Cerebrospinal fluid quinolinic acid is strongly associated with delirium and mortality in hip-fracture patients.

BACKGROUNDThe kynurenine pathway (KP) has been identified as a potential mediator linking acute illness to cognitive dysfunction by generating neuroactive metabolites in response to inflammation. Delirium (acute confusion) is a common complication of acute illness and is associated with increased risk of dementia and mortality. However, the molecular mechanisms underlying delirium, particularly in relation to the KP, remain elusive.METHODSWe undertook a multicenter observational study with 586 hospitalized patients (248 with delirium) and investigated associations between delirium and KP metabolites measured in cerebrospinal fluid (CSF) and serum by targeted metabolomics. We also explored associations between KP metabolites and markers of neuronal damage and 1-year mortality.RESULTSIn delirium, we found concentrations of the neurotoxic metabolite quinolinic acid in CSF (CSF-QA) (OR 2.26 [1.78, 2.87], P < 0.001) to be increased and also found increases in several other KP metabolites in serum and CSF. In addition, CSF-QA was associated with the neuronal damage marker neurofilament light chain (NfL) (ß 0.43, P < 0.001) and was a strong predictor of 1-year mortality (HR 4.35 [2.93, 6.45] for CSF-QA ≥ 100 nmol/L, P < 0.001). The associations between CSF-QA and delirium, neuronal damage, and mortality remained highly significant following adjustment for confounders and multiple comparisons.CONCLUSIONOur data identified how systemic inflammation, neurotoxicity, and delirium are strongly linked via the KP and should inform future delirium prevention and treatment clinical trials that target enzymes of the KP.FUNDINGNorwegian Health Association and South-Eastern Norway Regional Health Authorities.

Lyme neuroborreliosis with encephalitis; a systematic literature review and a Scandinavian cohort study.

BACKGROUND: Lyme neuroborreliosis (LNB) presenting with encephalitis is rare and scarcely described. OBJECTIVES: To describe the available literature on LNB encephalitis and to characterize this patient group through a Scandinavian retrospective cohort study. DATA SOURCES: Medline, Embase, Scopus, Cochrane library. STUDY ELIGIBILITY CRITERIA: There was no discrimination on study type, time of publication or language. PARTICIPANTS: Review: All articles with definite LNB and confirmed/possible encephalitis. COHORT: LNB cohorts from Denmark, Sweden and Norway 1990-2019 were screened for patients with encephalitis. METHODS: Review: Adhering to PRISMA guidelines; two authors extracted reviews and assessed quality of studies. COHORT: Data on demography, symptoms, cerebrospinal fluid findings, differential diagnostic examinations, treatment, residual symptoms, 1-year mortality were registered. RESULTS: Review: 2330 articles screened on title/abstract, 281 full texts, yielding 42 articles (case reports/series or cohort studies), including 45 patients from 18 countries spanning 35 years. Altered mental status ranged from personality changes and confusion to unconsciousness. Common focal symptoms were hemiparesis, ataxia and dysarthria; seven patients had seizures. Median time from symptom onset to hospital was 2 weeks (IQR 2-90 days). Of 38 patients with available follow-up after median 12 months (IQR 5-13), 32 had fully or partially recovered, two had died. COHORT: Thirty-five patients (median age 67 years, IQR 48-76) were included. The encephalitis prevalence was 3.3% (95% CI 2.2-4.4%) among 1019 screened LNB patients. Frequent encephalitis symptoms were confusion, personality changes, aphasia, ataxia. EEGs and neuroimaging showed encephalitis in 93.8% and 20.6%, respectively. Median delay from symptom onset to hospital was 14 days (IQR 7-34), with further 7 days (IQR 3-34) delay until targeted therapy. At follow-up (median 298 days post-treatment; IQR 113-389), 65.6% had residual symptoms. None had died. CONCLUSIONS: This study shows that encephalitis is an uncommon, but likely overlooked clinical manifestation of LNB. As the high frequency of residual symptoms may be related to prolonged treatment delay, prompt LNB testing of patients with encephalitis in Borrelia burgdorferi-endemic areas should be considered.

A man in his seventies with pleural effusion, knee pain and dysarthria following open heart surgery. / En mann i 70-årene med pleuravæske, knesmerter og dysartri etter åpen hjertekirurgi.

BACKGROUND: Patients receiving immunosuppressive therapy are vulnerable to infections. The wide range of possible causative pathogens, often with unusual manifestations and/or confounding comorbidity, are challenging for diagnosis and treatment. CASE PRESENTATION: An active man in his seventies developed recurrent pleural effusions, peripheral oedemas and fatigue, diagnosed as post-cardiotomy syndrome, within four months of open heart surgery and ablation due to aortic stenosis and atrial fibrillation. Following initial improvement on colchicine and corticosteroids, he deteriorated with respiratory symptoms, dysarthria and knee pain. Investigations revealed abscesses in brain and soft tissue with growth of Nocardia spp. Completion of the long-term broad-spectrum antibiotic treatment was challenging. INTERPRETATION: Systemic nocardiosis that developed in a patient on corticosteroid treatment, initiated to treat post-cardiotomy syndrome, highlights the risk of opportunistic infections by widely used drugs. The case also illustrates the importance of interdisciplinary collaboration for diagnosis and treatment.

Cerebrospinal fluid catecholamines in delirium and dementia.

Dopamine and noradrenaline are functionally connected to delirium and have been targets for pharmacological interventions but the biochemical evidence to support this notion is limited. To study the CSF levels of dopamine, noradrenaline and the third catecholamine adrenaline in delirium and dementia, these were quantified in three patient cohorts: (i) cognitively normal elderly patients (n = 122); (ii) hip fracture patients with or without delirium and dementia (n = 118); and (iii) patients with delirium precipitated by another medical condition (medical delirium, n = 26). Delirium was assessed by the Confusion Assessment Method. The hip fracture cohort had higher CSF levels of noradrenaline and adrenaline than the two other cohorts (both P < 0.001). Within the hip fracture cohort those with delirium (n = 65) had lower CSF adrenaline and dopamine levels than those without delirium (n = 52, P = 0.03, P = 0.002). Similarly, the medical delirium patients had lower CSF dopamine levels than the cognitively normal elderly (P < 0.001). Age did not correlate with the CSF catecholamine levels. These findings with lower CSF dopamine levels in hip fracture- and medical delirium patients challenge the theory of dopamine excess in delirium and question use of antipsychotics in delirium. The use of alpha-2 agonists with the potential to reduce noradrenaline release needs further examination.

Blood neurofilament light concentration at admittance: a potential prognostic marker in COVID-19.

OBJECTIVE: To test the hypotheses that blood biomarkers for nervous system injury, serum concentrations of neurofilament light chain protein (NfL) and glial fibrillary acidic protein (GFAp) can serve as biomarkers for disease severity in COVID-19 patients. METHODS: Forty-seven inpatients with confirmed COVID-19 had blood samples drawn on admission for assessing serum biomarkers of CNS injury by Single molecule array (Simoa), NfL and GFAp. Concentrations of NfL and GFAp were analyzed in relation to symptoms, clinical signs, inflammatory biomarkers and clinical outcomes. We used multivariate linear models to test for differences in biomarker concentrations in the subgroups, accounting for confounding effects. RESULTS: In total, 21% (n = 10) of the patients were admitted to an intensive care unit, and the overall mortality rate was 13% (n = 6). Non-survivors had higher serum concentrations of NfL (p < 0.001) upon admission than patients who were discharged alive both in adjusted analyses (p = 2.6 × 10-7) and unadjusted analyses (p = 0.001). The concentrations of NfL in non-survivors increased over repeated measurements; whereas, the concentrations in survivors were stable. The GFAp concentration was also significantly higher in non-survivors than survivors (p = 0.02). CONCLUSION: Increased concentrations of NfL and GFAp in COVID-19 patients on admission may indicate increased mortality risk. Measurement of blood biomarkers for nervous system injury can be useful to detect and monitor CNS injury in COVID-19.

The burden of herpes zoster disease in Norway.

BACKGROUND: No national vaccination program against herpes zoster (HZ) is currently in place in Norway. We aimed to quantify the burden of medically attended HZ to assess the need for a vaccination program. METHODS: We linked data from several health registries to identify medically attended HZ cases during 2008-2014 and HZ-associated deaths during1996-2012 in the entire population of Norway. We calculated HZ incidences for primary and hospital care by age, sex, type of health encounter, vaccination status, and co-morbidities among hospital patients. We also estimated HZ-associated mortality and case-fatality. RESULTS: The study included 82,064 HZ patients, of whom none were reported as vaccinated against HZ. The crude annual incidence of HZ was 227.1 cases per 100,000 in primary healthcare and 24.8 cases per 100,000 in hospitals. Incidence rates were higher in adults aged ≥50 years (461 per 100,000 in primary care and 57 per 100,000 in hospitals), and women than in men both in primary healthcare (267 vs 188 per 100,000), and hospitals (28 vs 22 per 100,000). Among hospital patients, 47% had complicated zoster and 25% had comorbidities, according to the Charlson comorbidity index. The duration of hospital stay (median 4 days) increased with the severity of comorbidities. The estimated mortality rate was 0.18 per 100,000; and in-hospital case-fatality rate was 1.04%. CONCLUSIONS: Medically attended HZ poses a substantial burden in the Norwegian healthcare sector. The majority of the zoster cases occurred among adults aged ≥50 years - the group eligible for zoster vaccination - and increased use of zoster vaccination may be warranted, especially among persons with co-morbidities.

Encephalitis and aseptic meningitis: short-term and long-term outcome, quality of life and neuropsychological functioning.

For those surviving encephalitis, the influence on daily life of patients and their relatives may be substantial. In contrast, the prognosis after aseptic meningitis (ASM) is considered good. In this prospective study in patients with encephalitis (n = 20) and ASM (n = 46), we show that both groups experienced reduced Health Related Quality of Life (HRQoL) at two months after discharge, and that workability was reduced in 37% of the patients with ASM. However, 12 months after discharge no neuropsychological deficits were detected in the ASM group, whereas patients with encephalitis had lower scores on tests of fine motor and psychomotor skills as well as on learning and memory. We also found that for patients with encephalitis, neopterin, as a marker of Th1 cell induced macrophage activation, and a putatively neurotoxic ratio of the kynurenine pathway (KP) measured during the acute phase was associated with lower HRQoL. Our data show that not only encephalitis, but also ASM has substantial short-term influence on HRQoL and workability. For patients with encephalitis we suggest a link between immune activation and activation of the KP during the acute phase with impaired HRQoL.

To what extent can clinical characteristics be used to distinguish encephalitis from encephalopathy of other causes? Results from a prospective observational study.

BACKGROUND: Recognizing patients with encephalitis may be challenging. The cardinal symptom, encephalopathy, has a wide array of differential diagnoses. In this prospective study we aimed to explore the etiology of encephalitis and to assess the diagnostic accuracy of symptoms and clinical findings in patients with encephalitis in an encephalopathic population. METHODS: Patients with acute onset of encephalopathy (n = 136) were prospectively enrolled from January 2014-December 2015 at Oslo University Hospital, Ullevaal. Clinical and biochemical characteristics of patients who met the case definition of encephalitis were compared to patients with encephalopathy of other causes. RESULTS: Among 136 patients with encephalopathy, 19 (14%) met the case-definition of encephalitis. For 117 patients other causes of encephalopathy were found, infection outside the CNS was the most common differential diagnosis. Etiology of encephalitis was confirmed in 53% (4 bacterial, 4 viral, 1 parasitic, and 1 autoimmune). Personality change, nausea, fever, focal neurology, recent travel history, and low inflammation markers were significantly more abundant in patients with encephalitis, but the diagnostic accuracy for individual parameters were low (area under the curve (AUC) < 0.7). The combination of fever (OR = 6.6, 95% CI, 1.6-28), nausea (OR = 8.9, 95% CI, 1.7-46) and a normal level of ESR (erythrocyte sedimentation rate < 17 mm/hr, OR = 6.9, 95% CI, 1.5-33) was significant in multivariate analysis with an AUC (area under the curve) of 0.85 (95% CI, 0.76-0.94). Moderately increased pleocytosis in CSF (5-100 × 106/L) further increased the diagnostic accuracy of this combination, AUC 0.90 (95% CI, 0.81-0.98). CONCLUSIONS: There is a wide diversity in differential diagnoses in patients with encephalopathy, and no single symptom or finding can be used to predict encephalitis with high accuracy in this group. The combination of fever, nausea and a low ESR in an encephalopathic population, increased the diagnostic accuracy of encephalitis compared to solitary parameters. The triad could be a useful clinical tool for early diagnosis of encephalitis, and these patients should be considered for further diagnostics such as lumbar puncture (LP).

CSF sTREM2 in delirium-relation to Alzheimer's disease CSF biomarkers Aß42, t-tau and p-tau.

BACKGROUND: Delirium and dementia share symptoms of cognitive dysfunctions, and mechanisms of neuroinflammation appear involved in both conditions. Triggering receptor expressed on myeloid cells 2 (TREM2) is linked to dementia and neurodegenerative disease. It encodes expression of an innate immune receptor in the brain expressed by microglia. The level of the soluble fragment of TREM2 (sTREM2) is reported to increase in the cerebrospinal fluid (CSF) already in prodromal and asymptomatic Alzheimer's disease. METHODS: We analyzed the level of CSF sTREM2 in relation to delirium and dementia. The study included patients with or without pre-existing dementia who underwent acute hip fracture surgery (n = 120), and some of the patients developed delirium (n = 65). A medical delirium cohort (n = 26) was also examined. ELISA was used to determine the level of sTREM2 in CSF. RESULTS: Delirium was associated with a higher level of CSF sTREM2 only among those without pre-existing dementia (p = 0.046, n = 15, n = 44), particularly among patients developing delirium after CSF sampling (p = 0.02, n = 7, n = 44). Between patients with dementia, there was no group difference, but the CSF sTREM2 level increased with waiting time for surgery (rS = 0.39, p = 0.002, n = 60) and correlated well with the CSF Alzheimer's disease biomarkers, Aß42, and t-tau/p-tau (rS = 0.40, p = 0.002, rS = 0.46, p < 0.001/ rS = 0.49, p < 0.001, n = 60). Among patients with dementia, the level of Aß38 and Aß40 also correlated positively with sTREM2 in CSF (Aß38MSDrS = 0.44, p = 0.001; Aß40MSDrS = 0.48, p < 0.001; Aß42MSDrS = 0.43, p < 0.001, n = 60). CONCLUSION: The findings reinforce the involvement of neuroinflammation in delirium, yet with separate responses in patients with or without pre-existing dementia. Our findings support the concept of primed microglia in neurodegenerative disease and central immune activation after a peripheral trauma in such patients. A CSF biomarker panel of neuroinflammation might be valuable to prevent delirium by identifying patients at risk.

High neopterin and IP-10 levels in cerebrospinal fluid are associated with neurotoxic tryptophan metabolites in acute central nervous system infections.

BACKGROUND: The host response to intruders in the central nervous system (CNS) may be beneficial but could also be harmful and responsible for neurologic symptoms and sequelae in CNS infections. This immune response induces the activation of the kynurenine pathway (KP) with the production of neuroactive metabolites. Herein, we explored cytokine and KP responses in cerebrospinal fluid (CSF) and serum in patients with encephalitis, aseptic, and bacterial meningitis. METHODS: Cytokines were measured in CSF and serum by multiplex assay in adult patients with encephalitis of infectious, autoimmune or unknown etiology (n = 10), aseptic meningitis (ASM, n = 25), acute bacterial meningitis (ABM, n = 6), and disease control patients with similar symptoms but without pleocytosis in CSF (n = 42). Liquid chromatography-tandem mass spectrometry (LC-MS/ MS) was used to measure KP metabolites in CSF and serum. RESULTS: A characteristic pattern of increasing cytokine levels and KP metabolites was found in CSF from encephalitis to ASM, with the highest levels in ABM. In ASM and ABM, most inflammatory mediators, including IL-6, IL-8, and IFN-inducible protein-10 (IP-10), showed markedly elevated levels in CSF compared with serum, indicating production within the CNS. In contrast to most mediators, the highest level of IP-10 was found in the ASM group, suggesting a potential role for IP-10 in aseptic/viral meningitis. Neopterin and IP-10 were associated with marked changes in KP metabolites in CSF with increasing kynurenine/tryptophan ratio reflecting indoleamine 2,3-dioxygenase activity. Neopterin, a marker of IFN-γ activity, was associated with an unfavorable balance between neuroprotective and neurotoxic tryptophan metabolites. CONCLUSION: We show that parenchymal and meningeal inflammations in CNS share a characteristic cytokine profile with a general immune response in the CSF with limited influence from the systemic circulation. IFN-γ activity, assessed by neopterin and IP-10 levels, may play a role in the activation of the KP pathway in these patients, potentially mediating neurotoxic effects.

Imaging in Lyme neuroborreliosis.

Lyme neuroborreliosis (LNB) is a tick-borne spirochetal infection with a broad spectrum of imaging pathology. For individuals who live in or have travelled to areas where ticks reside, LNB should be considered among differential diagnoses when clinical manifestations from the nervous system occur. Radiculitis, meningitis and facial palsy are commonly encountered, while peripheral neuropathy, myelitis, meningoencephalitis and cerebral vasculitis are rarer manifestations of LNB. Cerebrospinal fluid (CSF) analysis and serology are key investigations in patient workup. The primary role of imaging is to rule out other reasons for the neurological symptoms. It is therefore important to know the diversity of possible imaging findings from the infection itself. There may be no imaging abnormality, or findings suggestive of neuritis, meningitis, myelitis, encephalitis or vasculitis. White matter lesions are not a prominent feature of LNB. Insight into LNB clinical presentation, laboratory test methods and spectrum of imaging pathology will aid in the multidisciplinary interaction that often is imperative to achieve an efficient patient workup and arrive at a correct diagnosis. This article can educate those engaged in imaging of the nervous system and serve as a comprehensive tool in clinical cases. KEY POINTS: • Diagnostic criteria for LNB emphasise exclusion of an alternative cause to the clinical symptoms. • MRI makes a crucial contribution in the diagnosis and follow-up of LNB. • MRI may have normal findings, or show neuritis, meningitis, myelitis, encephalitis or vasculitis. • White matter lesions are not a prominent feature of LNB.

Infectious encephalitis: a description of a Norwegian cohort.

BACKGROUND: Prompt recognition and rapid initiation of adequate treatment are important for the outcome of encephalitis. Despite extensive diagnostic testing, the causative agent often remains unknown. The aim of this study was to investigate in how many patients the causative agent was found. METHODS: Adults (≥ 18 y) diagnosed with ICD codes indicating encephalitis between 2000 and 2009 at Oslo University Hospital, Ullevål were retrospectively studied. Causative agents, clinical presentation, and demographic characteristics were registered. Those with an identified causative agent were compared to those for whom no agent could be found. RESULTS: Of 136 registered patients, 70 were included in the study. Sixty-six did not fulfil our inclusion criteria or were diagnosed with other, more probable conditions. The causative agent was found in 30/70 (43%) patients; herpes simplex type 1 (10/70, 14%) and varicella zoster virus (6/70, 9%) were the most frequently identified agents. A bacterial cause was found in 6/70 (9%). Patients with an identified agent were more often men and had been ill longer than those for whom no agent could be found. Computed tomography and magnetic resonance imaging were more likely to be abnormal in those patients where a causative agent was found. Five of the 70 (7%) patients died of the infection. The identification rate did not increase during the study period. CONCLUSIONS: The diagnosis of encephalitis remains a challenge, and in many patients no causative agent is found. Clinically, immune-mediated encephalitis cannot be differentiated from infectious encephalitis and represents an important differential diagnosis. More knowledge is needed to improve our diagnostic skills.