Neurocritical Care

, Volume 30, Issue 1, pp 207–215 | Cite as

Electrographic Seizures in Patients with Acute Encephalitis

  • Tanuwong Viarasilpa
  • Nicha Panyavachiraporn
  • Gamaleldin Osman
  • Christopher Parres
  • Panayiotis Varelas
  • Meredith Van Harn
  • Stephan A. MayerEmail author
Original Article



Clinical seizures and status epilepticus are frequent complications of encephalitis, can lead to depressed level of consciousness, and are associated with poor outcome. We sought to determine the frequency, risk factors, and clinical impact of electrographic seizures detected with continuing electroencephalography (cEEG) in patients with encephalitis and altered level of consciousness.


We retrospectively identified all patients with presumed or definite viral or autoimmune encephalitis who underwent cEEG monitoring at Henry Ford Hospital from January 2012 to October 2017. Clinical data and cEEG monitoring reports were abstracted and recorded. The primary outcome was electrographic seizures detected by cEEG.


Of 1,735 patients who underwent a minimum of 12 h of cEEG monitoring, we identified 54 with a verified discharge diagnosis of encephalitis. Twenty-two of these patients (41%) had electrographic seizures on cEEG. Compared with encephalitis patients without seizures, electrographic seizures were associated with lower serum sodium levels (137 ± 5 vs 141 ± 7, P = 0.027) and more often were on antiepileptic therapy (100% vs 78%, P = 0.033) on the first day of monitoring. Seizures were also associated with a higher frequency of cortical imaging abnormalities (68% vs 28%, P = 0.005), lateralized periodic discharges (LPDs; 50% vs 16%, P = 0.014), delta background frequency (81% vs 45%, P = 0.010), low or suppressed voltage (96% vs 62%, P = 0.005), and focal slowing (86% vs 47%, P = 0.004). There was no association between electrographic seizures and clinical outcome at discharge.


Electrographic seizures occur in approximately 40% of patients with acute encephalitis. Low serum sodium, cortical imaging abnormalities, and on cEEG LPDs and background abnormalities are associated factors. The lack of association with short-term outcome suggests that with aggressive treatment, the clinical impact of electrographic seizures in encephalitis can be minimized.


Seizures Encephalitis Electroencephalography 


Authors Contribution

TV had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis, performed data collection, analysis and interpretation, drafted and revised the manuscript. NP performed data collection, analysis and interpretation, assisted in drafting and revised the manuscript. GO performed data collection, data review and interpretation, and revised the manuscript. CP designed the study, performed data review and interpretation, and revised the manuscript. PV performed data collection and revised the manuscript. MVH performed the statistical analysis. SAM designed the study and data analysis, performed data review and interpretation, drafted and revised the manuscript. All authors have read and approved the final manuscript and agree to be accountable for all aspects of the work.

Source of Support

This study was funded by Educational and Research Fund from Department of Neurology of Henry Ford Hospital. Tanuwong Viarasilpa has received funding from Siriraj Hospital, Mahidol University, Bangkok, Thailand. The funding sources had no role in the collection, analysis, or interpretation of the data.

Compliance of Ethical Standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical Approval

This study was approved by the Henry Ford Hospital Institutional Review Board.

Supplementary material

12028_2018_599_MOESM1_ESM.docx (31 kb)
Supplementary material 1 (DOCX 31 kb)


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Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature and Neurocritical Care Society 2018

Authors and Affiliations

  1. 1.Department of NeurologyHenry Ford HospitalDetroitUSA
  2. 2.Division of Critical Care, Department of Medicine, Siriraj HospitalMahidol UniversityBangkokThailand
  3. 3.Department of Public Health Sciences of Henry Ford Health SystemDetroitUSA

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