Case report: A 33 years-old alcoholic male with diarrhea and progressive muscle weakness mimicking Guillain-Barré syndrome.

Background: A subacute manifestation of muscle weakness in temporal association with a diarrheal intestinal infection is always suspicious of Guillain-Barré syndrome (GBS). GBS is characterized as an acute inflammatory polyneuroradiculopathy, mediated by cross-reacting autoantibodies and typically triggered by various infections, vaccinations or other causes. Hyponatremia can be associated with GBS and is usually seen in more severe cases. However, the presence of relevant hyponatremia in a case suspicious of GBS can lead to a diagnostic dilemma. We here describe an intriguing and initially misleading case of hyponatremia mimicking GBS, where repeated and thorough electrophysiology was the key to the correct diagnosis. Case presentation: A 33 years-old man with a history of severe alcohol dependence and schizophrenia developed progressive muscle weakness in the course of a preceding episode of diarrhea. Neurological examination revealed a leg-accentuated tetraplegia with global areflexia. There was also a complex oculomotor dysfunction. Laboratory tests showed hyponatremia of 110 mM. Cerebrospinal-fluid analysis showed a normal cell count and cytological evaluation, protein concentration within the normal range. Electroneurography showed severe proximal nerve conduction block as evidenced by prolonged F-wave latency and distal nerve conduction block as evidenced by prolonged distal motor latencies and reduced motor nerve conduction velocities (NCV) in all peripheral nerves examined. GBS-associated ganglioside autoantibodies were absent. After compensation of hyponatremia alone, muscle weakness improved rapidly and nerve conduction velocity improved similarly. These dynamics are not consistent with GBS and unnecessary immunoglobulin treatment could be avoided. Conclusion: Suspicion of GBS in the presence of relevant hyponatremia can be misleading as hyponatremia is able to mimic GBS. We demonstrate that repeated and accurate nerve conduction studies together with F-wave diagnostics is helpful to make the correct diagnosis. We discuss the mechanisms of the causes of hyponatremia in GBS and contrast these with the electropyhsiological changes caused by hyponatremia itself. The correct diagnosis will prevent the uncritical use of intravenous immunoglobulins and save unnecessary costs. Also, a possible aggravation of the hyponatremia by immunoglobulin treatment can be averted.

Cerebrospinal fluid findings in COVID-19: a multicenter study of 150 lumbar punctures in 127 patients.

BACKGROUND: Comprehensive data on the cerebrospinal fluid (CSF) profile in patients with COVID-19 and neurological involvement from large-scale multicenter studies are missing so far. OBJECTIVE: To analyze systematically the CSF profile in COVID-19. METHODS: Retrospective analysis of 150 lumbar punctures in 127 patients with PCR-proven COVID-19 and neurological symptoms seen at 17 European university centers RESULTS: The most frequent pathological finding was blood-CSF barrier (BCB) dysfunction (median QAlb 11.4 [6.72-50.8]), which was present in 58/116 (50%) samples from patients without pre-/coexisting CNS diseases (group I). QAlb remained elevated > 14d (47.6%) and even > 30d (55.6%) after neurological onset. CSF total protein was elevated in 54/118 (45.8%) samples (median 65.35 mg/dl [45.3-240.4]) and strongly correlated with QAlb. The CSF white cell count (WCC) was increased in 14/128 (11%) samples (mostly lympho-monocytic; median 10 cells/µl, > 100 in only 4). An albuminocytological dissociation (ACD) was found in 43/115 (37.4%) samples. CSF L-lactate was increased in 26/109 (24%; median 3.04 mmol/l [2.2-4]). CSF-IgG was elevated in 50/100 (50%), but was of peripheral origin, since QIgG was normal in almost all cases, as were QIgA and QIgM. In 58/103 samples (56%) pattern 4 oligoclonal bands (OCB) compatible with systemic inflammation were present, while CSF-restricted OCB were found in only 2/103 (1.9%). SARS-CoV-2-CSF-PCR was negative in 76/76 samples. Routine CSF findings were normal in 35%. Cytokine levels were frequently elevated in the CSF (often associated with BCB dysfunction) and serum, partly remaining positive at high levels for weeks/months (939 tests). Of note, a positive SARS-CoV-2-IgG-antibody index (AI) was found in 2/19 (10.5%) patients which was associated with unusually high WCC in both of them and a strongly increased interleukin-6 (IL-6) index in one (not tested in the other). Anti-neuronal/anti-glial autoantibodies were mostly absent in the CSF and serum (1509 tests). In samples from patients with pre-/coexisting CNS disorders (group II [N = 19]; including multiple sclerosis, JC-virus-associated immune reconstitution inflammatory syndrome, HSV/VZV encephalitis/meningitis, CNS lymphoma, anti-Yo syndrome, subarachnoid hemorrhage), CSF findings were mostly representative of the respective disease. CONCLUSIONS: The CSF profile in COVID-19 with neurological symptoms is mainly characterized by BCB disruption in the absence of intrathecal inflammation, compatible with cerebrospinal endotheliopathy. Persistent BCB dysfunction and elevated cytokine levels may contribute to both acute symptoms and 'long COVID'. Direct infection of the CNS with SARS-CoV-2, if occurring at all, seems to be rare. Broad differential diagnostic considerations are recommended to avoid misinterpretation of treatable coexisting neurological disorders as complications of COVID-19.

Tick-borne encephalitis virus (TBEV) prevalence in field-collected ticks (Ixodes ricinus) and phylogenetic, structural and virulence analysis in a TBE high-risk endemic area in southwestern Germany.

BACKGROUND: Tick-borne encephalitis (TBE) is the most common viral CNS infection with incidences much higher than all other virus infections together in many risk areas of central and eastern Europe. The Odenwald Hill region (OWH) in southwestern Germany is classified as a TBE risk region and frequent case numbers but also more severe infections have been reported within the past decade. The objective of the present study was to survey the prevalence of tick-borne encephalitis virus (TBEV) in Ixodes ricinus and to associate TBEV genetic findings with TBE infections in the OWH. METHODS: Ticks were collected by the flagging methods supported by a crowdsourcing project implementing the interested public as collectors to cover completely and collect randomly a 3532 km2 area of the OWH TBE risk region. Prevalence of TBEV in I. ricinus was analysed by reversed transcription quantitative real-time PCR. Phylogeographic analysis was performed to classify OWH TBEV isolates within a European network of known TBEV strains. Mutational sequence analysis including 3D modelling of envelope protein pE was performed and based on a clinical database, a spatial association of TBE case frequency and severity was undertaken. RESULTS: Using the crowd sourcing approach we could analyse a total of 17,893 ticks. The prevalence of TBEV in I. ricinus in the OWH varied, depending on analysed districts from 0.12% to 0% (mean 0.04%). Calculated minimum infection rate (MIR) was one decimal power higher. All TBEV isolates belonged to the European subtype. Sequence analysis revealed a discontinuous segregation pattern of OWH isolates with two putative different lineages and a spatial association of two isolates with increased TBE case numbers as well as exceptional severe to fatal infection courses. CONCLUSIONS: TBEV prevalence within the OWH risk regions is comparatively low which is probably due to our methodological approach and may more likely reflect prevalence of natural TBEV foci. As for other European regions, TBEV genetics show a discontinuous phylogeny indicating among others an association with bird migration. Mutations within the pE gene are associated with more frequent, severe and fatal TBE infections in the OWH risk region.

Clinical outcome and cerebrospinal fluid profiles in patients with tick-borne encephalitis and prior vaccination history.

BACKGROUND: Tick-borne encephalitis (TBE) is endemic in southern and eastern districts of Germany. Approximately 10-14% of the infected individuals suffer from long-term disability and in 1.5-3.6% the course is fatal. Two well-tolerated vaccines are available, which provide high protection and which have been confirmed in several field studies. Here we investigate clinical course, long-term outcome and cerebrospinal fluid (CSF) characteristics of TBE cases with a prior history of any vaccination as well as real vaccination breakthrough (VBT). METHODS: A case series of 11 patients with a prior history of vaccination, part of a recently published lager cohort of 111 TBE cases. Evaluation included clinical data, degree of disability (modified RANKIN scale, mRS) and analysis of CSF and serum samples. Furthermore, metadata for extended analysis on clinical outcome of TBE with VBT were analysed. RESULTS: One patient had a clear VBT and ten of them had irregular vaccinations schedules (IVS). Infection severity did not differ in patients with IVS as compared to a non-vaccinated control cohort (median mRS: both 3.0) but these patients showed a stronger cellular immune response as measured by CSF pleocytosis (IVS, 205 cells/µL versus non-vaccinated control, 114 cell/µL, P < 0.05) and by differential pattern of CSF (intrathecal) immunoglobulin synthesis. However, shift analysis of VBT metadata using linear-by-linear association revealed a more serious course of TBE in patients with VBT than in a non-vaccinated control cohort (χ2 = 9.95, P = 0.002). Furthermore, ordinal logistic regression analysis showed that VBT patients had an age-corrected, 2.65 fold (CI: 1.110-6.328; χ2 = 4.813; p = 0.028) significant higher risk to suffer from moderate or severe infections, respectively. CONCLUSION: A history of IVS surprisingly seems to have no impact on the clinical course of TBE but may leave marks in the specific brain immune response. VBT patients, however, carry an age-independent, significant risk to experience a severe infection.

Predictors, Neuroimaging Characteristics and Long-Term Outcome of Severe European Tick-Borne Encephalitis: A Prospective Cohort Study.

BACKGROUND AND OBJECTIVES: Tick-borne encephalitis (TBE) still represents a considerable medical and health economic problem in Europe and entails a potential threat to travellers. The aim of this study was to characterise the conditions of severe TBE by precisely recording its clinical variants, the related neuroimaging features, and the variant-specific long-term outcome and by identifying predictors for severe courses. METHODS: A cohort of 111 TBE patients (median age 51, range 17-75 years; 42% females) was analysed prospectively. Data were acquired from the department of neurology, University Hospital Heidelberg, and the infectious diseases registry of the Robert-Koch institute Berlin. Neurological status was ascertained by protocol at admission and discharge and the degree of disability was scored using the modified RANKIN Scale (mRS; clinical score addressing neurological disability, range from 0, healthy to 6, dead) at admission and at follow-up. Follow-up examination was conducted by means of a telephone interview. To identify independent predictors for severe TBE and functional outcome, modelled logistic regression was performed. MRI changes were correlated with infection variants. To assess alpha-motor neuron injury patterns, we used high-resolution magnetic resonance neurography (hrMRN). Analyses were performed at the Department of Neurology, University Hospital, University of Heidelberg from April 2004 through September 2014. RESULTS: Acute course: 3.6% of patients died during the acute infection. All patients with a lethal course suffered from meningoencephaloradiculitis (MER, 14.4% of the cohort), which is associated with a significantly higher risk of requiring intensive care (p = 0.004) and mechanical ventilation (p<0.001) than menigoencephalitis (ME, 27.9% of the cohort). At admission, both MER and ME groups were severely affected, with the MER group having a statistically higher mRS score (median of 5 in the MER groups versus 4 in the ME group; p<0.001). Long-term outcome: outcome for MER was considerably worse (median mRS = 4) than for ME (mRS = 1, p<0.0001) and meningitis (mRS = 0, 57.7% of the cohort). RISK FACTORS: advanced age (p<0.001) and male gender (p = 0.043) are independent risk factors for a severe infection course. Furthermore, we identified pre-existing diabetes mellitus (p = 0.024) as an independent risk factor for MER. In MER, alpha-motor neuron injury accounts for the poor prognosis confirmed by hrMRN. CONCLUSION AND RELEVANCE: These data provide critical information for neurologists and other health professionals to use in evaluating TBEV patients who live in or travel to endemic areas. This information can be used to classify clinical presentation and estimate infection-associated complications and individual prognosis. Furthermore, the risk for severe, disabling infections in older patients should prompt general practitioners to recommend and encourage vaccination to those patients living in or travelling to endemic areas.

Identification and characterization of a unique role for EDB fibronectin in phagocytosis.

UNLABELLED: Plasma fibronectin is a circulating protein that facilitates phagocytosis by connecting bacteria to immune cells. A fibronectin isoform, which includes a sequence of 90 AA called extra-domain B (EDB), is synthesized de novo at the messenger RNA (mRNA) level in immune cells, but the reason for its expression remains elusive. We detected an 80-fold increase in EDB-containing fibronectin in the cerebrospinal fluid of patients with bacterial meningitis that was most pronounced in staphylococcal infections. A role for this isoform in phagocytosis was further suggested by enhanced EDB fibronectin release after internalization of Staphylococcus aureus in vitro. Using transgenic mouse models, we established that immune cell production of fibronectin contributes to phagocytosis, more so than circulating plasma fibronectin, and that accentuated release of EDB-containing fibronectin by immune cells improved phagocytosis. In line with this, administration of EDB fibronectin enhanced in vitro phagocytosis to a larger extent than plasma fibronectin. This enhancement was mediated by αvß3 integrin as shown using inhibitors or cells from ß3 integrin knockout mice. Thus, we identified both a novel function for EDB fibronectin in augmenting phagocytosis over circulating plasma fibronectin, as well as the mediating receptor. Our data also establish for the first time, a direct role for ß3 integrin in bacterial phagocytosis in mammals. KEY MESSAGES: • Fibronectin containing an extra domain called EDB is released in bacterial meningitis. • EDB-containing fibronectin enhances phagocytosis more than plasma fibronectin. • The enhancement is mediated by activation of αvß3 integrin in the presence of EDB.

A simple method to quickly and simultaneously purify and enrich intact rat brain microcapillaries and endothelial and glial cells for ex vivo studies and cell culture.

The blood-brain barrier is morphologically composed of cerebral microcapillary endothelium through its tight junctions. It serves as a mechanical, metabolic and cellular barrier and can also protect the brain from pathogen invasion. Many brain diseases involve a disturbance of blood-brain barrier function either as a consequence of a noxa or as primary failure. In vitro models of the blood-brain barrier are suitable tools to study drug transport, pathogen transmigration and leukocyte diapedesis across the cerebral endothelium. Such models have previously been derived mainly from porcine or bovine brain tissues. We describe here a simple method by which rat cerebral microcapillaries and cells of glial origin can be quickly and simultaneously purified. By using a capillary fragment size restriction method based on glass bead columns different fractions can be separated: vital, long capillary fragments for ex vivo uptake studies and smaller capillary fragments for endothelial culture. Furthermore, fractions can be obtained for astroglial and oligodendroglial cell cultures. With this method both microcapillary enrichment and glial cell purification are quickly achieved, which reduces expenditure, number of required animals and laboratory working time.

Herpes simplex virus encephalitis despite normal cell count in the cerebrospinal fluid.

OBJECTIVES: To describe herpes simplex virus encephalitis despite normal cell count in the cerebrospinal fluid in patients with malignoma after whole brain irradiation. INTERVENTIONS: Blood and cerebrospinal fluid analysis and magnetic resonance imaging. MEASUREMENTS AND MAIN RESULTS: Three male and two female patients with malignoma and a recent history of whole-brain irradiation presented with impaired consciousness with or without epileptic seizure. Although cerebrospinal fluid analysis revealed a normal cell count, herpes simplex virus DNA was detected in all samples by polymerase chain reaction. CONCLUSIONS: In patients with impaired consciousness, epileptic seizure, or temporal lobe symptoms of new onset and a recent history of brain irradiation with normal cerebrospinal fluid, an atypical anergic course of herpes simplex virus encephalitis should be considered. Herpes simplex virus polymerase chain reaction should be used as method of choice to detect herpes simplex virus genomes as early as possible rather than relying on routine cerebrospinal fluid parameters. Importantly, antiviral therapy should be started without delay in any case of faint suspicion and should be continued until herpes simplex virus encephalitis is clearly ruled out.

An unusual case of optic neuritis.

Optic neuritis is a frequent disease with well established tests and therapeutic strategies. However, possible differential diagnoses cover a broad spectrum. Therefore, clinical work-up can be challenging and routine testing and therapies may not be sufficient. In this case, a 26 year old female is described who presented with clinical features of optic neuritis, yet failed to respond to common therapeutic strategies and lost vision on the affected eye. Diagnostic nerve transection was performed, histopathology suggested inflammation. As the second nerve became affected, immunosuppressive therapy with cyclophosphamide was started and stopped further deterioration. Although additional molecular work-up of the transected nerve revealed clonal rearrangement of the B-cell-receptor-locus IgH, overall histopathologic features and the absence of systemic disease suggested an aggressive inflammatory process rather than lymphoma. Additional B-cell depletion with rituximab prompted significant and sustained visual improvement. This case emphasizes the necessity to consider rare differential diagnoses of optic neuritis, when uncommon features arise during the course of disease. Aggressive immunosuppression might be required to achieve stable improvement of vision.

Cerebral salt-wasting syndrome in a patient with neuroleptic malignant syndrome.

BACKGROUND: Hyponatremia associated with neuroleptic malignant syndrome has thus far been described as a syndrome of inappropriate secretion of antidiuretic hormone. OBJECTIVES: To ascertain and describe the role of cerebral salt-wasting syndrome as the cause of hyponatremia in a patient with neuroleptic malignant syndrome. PATIENT: A psychotic patient being treated with olanzapine presenting with sopor, muscle rigidity, polyuria, tachycardia, pyrexia, and severe hyponatremia. METHODS: Serial serological examinations of plasma tonicity (sodium level and osmolality), brain natriuretic peptide, and antidiuretic hormone were performed, and sodium excretion and urine osmolality were determined from 24-hour urine collection. In addition, markers for rhabdomyolysis were monitored. RESULTS: The patient shows clear symptoms of cerebral salt-wasting syndrome in association with neuroleptic malignant syndrome, characterized by severe hyponatremia, volume depletion, and elevated brain natriuretic peptide but normal antidiuretic hormone levels. Cerebral salt-wasting syndrome improved under dantrolene sodium treatment and concomitant fluid and sodium replacement. CONCLUSION: Hyponatremia in patients with neuroleptic malignant syndrome might more likely reflect cerebral salt-wasting syndrome than a syndrome of inappropriate secretion of antidiuretic hormone as an additional aspect of autonomic dysregulation caused by antidopaminergic drugs.

Long-term behavioural changes after unilateral stereotactic cingulotomy in a case of therapy-resistant alcohol dependence.

We report the case of a female patient who had undergone a unilateral stereotactical anterior cingulotomy (AC) 20 years previously because of refractory alcohol dependence. After AC, the drinking behaviour switched from a chronic to an episodic one with fast losses of control accompanied by abnormal oral impulse-control behaviour. Relapses were stress- but not cue-induced and followed by long-term intervals of abstinence. In addition to an intended lesion of the left dorsal anterior cingulate cortex (ACC), MR images showed additional lesions within the left caudate body and the dorsal medial thalamic nucleus. Applying a neuropsychological test battery, we found disturbed divided attention and impaired executive function. From this, we conclude that the complex lesion pattern may contribute to some of the behavioural changes seen in our patient after AC. This hypothesis is supported by the neuropsychological deficits and the fact that the neuronal circuits, impaired by the lesions, are involved in addiction-specific behaviour. This case report further emphasizes the key role of the ACC and its connections in the maintenance of dependent behaviour.

Differential mRNA expression of neurotrophic factors GDNF, BDNF, and NT-3 in experimental herpes simplex virus encephalitis.

Glial cell line-derived neurotrophic factor (GDNF), brain-derived neurotrophic factor (BDNF), and neurotrophin-3 (NT-3) mRNA levels were studied in the course of murine herpes simplex virus encephalitis. Induction of GNDF and NT-3 (both P < 0.05) was found during acute encephalitis. Despite absence of clinical impairment, both neurotrophic factors were overexpressed 2 months (NT-3) and 6 months (GDNF) following infection (both P < 0.05). Neurotrophic factors play an important role in neuronal survival and recovery after acute injury to the central nervous system (CNS) and may represent an additional therapeutic target for treatment of viral encephalitis.

Fibroblast growth factor-2 requires glial-cell-line-derived neurotrophic factor for exerting its neuroprotective actions on glutamate-lesioned hippocampal neurons.

FGF-2 is a potent neurotrophic factor for several populations of CNS neurons and has been shown to protect hippocampal neurons from glutamate-induced cell death in vitro and in vivo. Mechanisms underlying the neurotrophic and protective actions of FGF-2 have been resolved only in part. Using glutamate-treated cultured hippocampal neurons we show that FGF-2 shares its neuroprotective capacity with GDNF. Hippocampal neurons express glial-cell-line-derived neurotrophic factor (GDNF), its receptors c-Ret and the lipid-anchored GDNF family receptor-alpha1 (GFRalpha-1), and the FGF receptor 1 (FGFR I). Neutralizing antibodies to GDNF abolish the neuroprotective effect of FGF-2. In support of the notion that GDNF is required to permit the protective effects of FGF-2 we find that FGF-2 up-regulates GDNF and GFRalpha-1 in hippocampal neurons. Furthermore, FGF-2-induced GDNF causes enhanced phosphorylation of c-Ret and the signaling components Akt and Erk. A putative downstream target of FGF-2 and GDNF are bcl-2 gene family members, whose mRNAs are differentially up-regulated by the two factors. Together, these data suggest that GDNF is an important protective factor for glutamate-lesioned hippocampal neurons and an essential mediator of the neuroprotective actions of FGF-2.