Neurocritical Care

, Volume 21, Issue 3, pp 476–482 | Cite as

High Risk for Seizures Following Subarachnoid Hemorrhage Regardless of Referral Bias

  • Kathryn L. O’Connor
  • M. Brandon Westover
  • Michael T. Phillips
  • Nicolae A. Iftimia
  • Deidre A. Buckley
  • Christopher S. Ogilvy
  • Mouhsin M. Shafi
  • Eric S. Rosenthal
Original Article



To investigate the frequency, predictors, and clinical impact of electrographic seizures in patients with high clinical or radiologic grade non-traumatic subarachnoid hemorrhage (SAH), independent of referral bias.


We compared rates of electrographic seizures and associated clinical variables and outcomes in patients with high clinical or radiologic grade non-traumatic SAH. Rates of electrographic seizure detection before and after institution of a guideline which made continuous EEG monitoring routine in this population were compared.


Electrographic seizures occurred in 17.6 % of patients monitored expressly because of clinically suspected subclinical seizures. In unselected patients, seizures still occurred in 9.6 % of all cases, and in 8.6 % of cases in which there was no a priori suspicion of seizures. The first seizure detected occurred 5.4 (IQR 2.9–7.3) days after onset of subarachnoid hemorrhage with three of eight patients (37.5 %) having the first recorded seizure more than 48 h following EEG initiation, and 2/8 (25 %) at more than 72 h following EEG initiation. High clinical grade was associated with poor outcome at time of hospital discharge; electrographic seizures were not associated with poor outcome.


Electrographic seizures occur at a relatively high rate in patients with non-traumatic SAH even after accounting for referral bias. The prolonged time to the first detected seizure in this cohort may reflect dynamic clinical features unique to the SAH population.


Subarachnoid hemorrhage Non-convulsive seizures Continuous electroencephalography 


Conflict of interest

Kathryn L. O’Connor, M. Brandon Westover, Michael T. Phillips, Nicolae A. Iftimia, Deidre A. Buckley, Christopher S. Ogilvy, Mouhsin M. Shafi, and Eric S. Rosenthal declare that they have no conflict of interest.


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Copyright information

© Springer Science+Business Media New York 2014

Authors and Affiliations

  • Kathryn L. O’Connor
    • 1
  • M. Brandon Westover
    • 1
  • Michael T. Phillips
    • 3
  • Nicolae A. Iftimia
    • 1
  • Deidre A. Buckley
    • 4
  • Christopher S. Ogilvy
    • 4
  • Mouhsin M. Shafi
    • 1
    • 2
  • Eric S. Rosenthal
    • 1
  1. 1.Department of NeurologyMassachusetts General HospitalBostonUSA
  2. 2.Department of NeurologyBeth Israel Deaconess Medical CenterBostonUSA
  3. 3.Department of NeurosurgeryMassachusetts General HospitalBostonUSA
  4. 4.Department of NeurosurgeryBeth Israel Deaconess Medical CenterBostonUSA

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