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  • Review Article
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Nonconvulsive status epilepticus in adults — insights into the invisible

Nature Reviews Neurology volume 12, pages 281–293 (2016)Cite this article

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Key Points

  • Nonconvulsive status epilepticus (NCSE) is defined as a continuous state of seizures without convulsions, or multiple nonconvulsive seizures for more than 30 min without interictal full recovery

  • The variable and subtle clinical features of NCSE make diagnosis and treatment challenging, as they can arise from other pathological conditions

  • The introduction of continuous electroencephalography and the characterization of electrographic criteria have delineated several NCSE types that are associated with different prognoses in various clinical settings

  • The classification of NCSE should mainly be based on aetiology, as the outcomes of NCSE are driven largely by the underlying pathology

  • Treatment of NCSE encompasses general intensive care, rapid administration of antiepilepic drugs, and treatment of the underlying or concomitant diseases

Abstract

Nonconvulsive status epilepticus (NCSE) is a state of continuous or repetitive seizures without convulsions. Owing to the nonspecific symptoms and considerable morbidity and mortality associated with NCSE, clinical research has focused on early diagnosis, risk stratification and seizure termination. The subtle symptoms and the necessity for electroencephalographic confirmation of seizures result in under-diagnosis with deleterious consequences. The introduction of continuous EEG to clinical practice, and the characterization of electrographic criteria have delineated a number of NCSE types that are associated with different prognoses in several clinical settings. Epidemiological studies have uncovered risk factors for NCSE; knowledge of these factors, together with particular clinical characteristics and EEG observations, enables tailored treatment. Despite these advances, NCSE can be refractory to antiepileptic drugs, necessitating further escalation of treatment. The presumptive escalation to anaesthetics, however, has recently been questioned owing to an association with increased mortality. This Review compiles epidemiological, clinical and diagnostic aspects of NCSE, and considers current treatment options and prognosis.

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Figure 1: Major symptoms of nonconvulsive status epilepticus.
Figure 2: Recommendations for the use of continuous electroencephalography (cEEG) monitoring in critical illnesses.
Figure 3: Recommendations for the treatment of nonconvulsive status epilepticus (NCSE) in the intensive care unit (ICU).

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Acknowledgements

R.S. is supported by the Scientific Society Basel, the Gottfried and Julia Bangerter-Rhyner Foundation, and the Foundation of the University of Basel for promotion of science and young investigators, all in Switzerland. P.W.K. is funded by a Qatar Research Foundation grant to investigate continuous EEG monitoring in status epilepticus.

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Authors and Affiliations

  1. Clinic for Intensive Care Medicine, University Hospital Basel, Petersgraben 4, Basel, Ch-4031, Switzerland

    Raoul Sutter & Saskia Semmlack

  2. Department of Neurology and Intensive Care Unit, University Hospital Basel, Petersgraben 4, Basel, CH-4031, Switzerland

    Raoul Sutter

  3. Department of Neurology, Johns Hopkins Bayview Medical Center, 301 Building 4940 Eastern Avenue, Baltimore, 21224, Maryland, USA

    Peter W. Kaplan

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  1. Raoul Sutter
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Contributions

R.S. and S.S. developed the concept of the Review, performed the literature search, and developed the tables and figures. All authors analyzed the data and wrote the manuscript. P.W.K. revised the manuscript before submission.

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Correspondence to Raoul Sutter.

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Competing interests

R.S has received travel grants from UCB Pharma and holds shares in Roche and Novartis. S.S. and P.W.K. declare no competing interests.

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Sutter, R., Semmlack, S. & Kaplan, P. Nonconvulsive status epilepticus in adults — insights into the invisible. Nat Rev Neurol 12, 281–293 (2016). https://doi.org/10.1038/nrneurol.2016.45

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