Evidence map›Paper›PMID 33369818›Full record

ArticleEuropean journal of neurology2021

Biomarkers for central nervous system injury in cerebrospinal fluid are elevated in COVID-19 and associated with neurological symptoms and disease severity.

Johan Virhammar, Anja Nääs, David Fällmar, Janet L Cunningham, Andrea Klang, Nicholas J Ashton, Sven Jackmann, Gabriel Westman, Robert Frithiof, Kaj Blennow and 3 more

Open access · hybridAbstract read
In one paragraph

Article in European journal of neurology, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 79 papers, 7 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
79citing papers in PubMed, 7 pooled it
10.1field-weighted citation impact, top 1% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

79 citing papers in PubMed, 7 syntheses or guidelines pooled it, 140 citations in OpenAlex.

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  12. Neurological, psychological, psychosocial complications of long-COVID and their management.Neurological sciences : official journal of the Italian Neurological Society and of the Italian Society of Clinical Neurophysiology · 2025
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19 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

13 authors at 3 institutions in 2 countries.

Johan VirhammarDepartment of Neuroscience, Neurology, Uppsala University, Uppsala, Sweden.ORCID 0000-0001-9901-2949
Anja NääsDepartment of Medical Sciences, Section of Infectious Diseases, Uppsala University, Uppsala, Sweden.
David FällmarDepartment of Surgical Sciences, Radiology, Uppsala University, Uppsala, Sweden.
Janet L CunninghamDepartment of Neuroscience, Psychiatry, Uppsala University, Uppsala, Sweden.
Andrea KlangDepartment of Neuroscience, Rehabilitation Medicine, Uppsala University, Uppsala, Sweden.
Nicholas J AshtonDepartment of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden.
Sven JackmannDepartment of Neuroscience, Neurology, Uppsala University, Uppsala, Sweden.
Gabriel WestmanDepartment of Medical Sciences, Section of Infectious Diseases, Uppsala University, Uppsala, Sweden.
Robert FrithiofDepartment of Surgical Sciences, Anaesthesiology and Intensive Care, Uppsala University, Uppsala, Sweden.
Kaj BlennowDepartment of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden.
Henrik ZetterbergDepartment of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden.
Eva KumlienDepartment of Neuroscience, Neurology, Uppsala University, Uppsala, Sweden.
Elham RostamiDepartment of Neuroscience, Neurosurgery, Uppsala University, Uppsala, Sweden.
Uppsala University · SESahlgrenska University Hospital · SEKing's College London · GB

Funding

Knut och Alice Wallenbergs StiftelseOpen Medicine FoundationScience for Life LaboratorySvenska LäkaresällskapetSvenska Sällskapet för Medicinsk ForskningVetenskapsrådet 2014-02569Vetenskapsrådet 2014-07606Vetenskapsrådet #2017-00915
6 · The paper itself

Abstract

background and purposeNeurological symptoms have been frequently reported in hospitalized patients with coronavirus disease 2019 (COVID-19), and biomarkers of central nervous system (CNS) injury are reported to be increased in plasma but not extensively studied in cerebrospinal fluid (CSF). This study examined CSF for biomarkers of CNS injury and other pathology in relation to neurological symptoms and disease severity in patients with neurological manifestations of COVID-19.

methodsNineteen patients with neurological symptoms and mild to critical COVID-19 were prospectively included. Extensive analysis of CSF, including measurement of biomarkers of CNS injury (neurofilament light chain [NfL] protein, glial fibrillary acidic protein [GFAp], and total tau), was performed and compared to neurological features and disease severity.

resultsNeurological symptoms included altered mental status (42%), headache (42%), and central (21%) and peripheral weakness (32%). Two patients demonstrated minor pleocytosis, and four patients had increased immunoglobulin G levels in CSF. Neuronal autoantibody testing using commercial tests was negative in all patients. Increased CSF levels of NfL protein, total tau, and GFAp were seen in 63%, 37%, and 16% of patients, respectively. Increased NfL protein correlated with disease severity, time in intensive care, and level of consciousness. NfL protein in CSF was higher in patients with central neurological symptoms.

conclusionsAlthough limited by the small sample size, our data suggest that levels of NfL protein, GFAp, and total tau in CSF are commonly elevated in patients with COVID-19 with neurological symptoms. This is in contrast to the standard CSF workup where pathological findings are scarce. NfL protein, in particular, is associated with central neurological symptoms and disease severity.

Indexed as

COVID-19Neurofilament ProteinsBiomarkersCentral Nervous SystemGlial Fibrillary Acidic ProteinHumansSARS-CoV-2Severity of Illness IndexBiomarkersGlial Fibrillary Acidic ProteinNeurofilament ProteinsCOVID-19GFApNfLSARS-CoV-2total tau

Identifiers

PMID33369818
PMCPMC8518988
OpenAlexW3114190045

What OpenQuestion holds

Textmetadata
LicenceCC BY-NC-ND
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.