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Current Treatment Options in Neurology
Published in: Current Treatment Options in Neurology 2/2016

01-02-2016 | Critical Care Neurology (K Sheth, Section Editor)

Understanding and Managing the Ictal-Interictal Continuum in Neurocritical Care

Authors: Adithya Sivaraju, MD, MHA, Emily J. Gilmore, MD, MS

Published in: Current Treatment Options in Neurology | Issue 2/2016

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Opinion statement

Continuous electroencephalographic (EEG) monitoring has become an invaluable tool for the assessment of brain function in critically ill patients. However, interpretation of EEG waveforms, especially in the intensive care unit (ICU) setting is fraught with ambiguity. The term ictal-interictal continuum encompasses EEG patterns that are potentially harmful and can cause neuronal injury. There are no clear guidelines on how to treat EEG patterns that lie on this continuum. We advocate the following approaches in a step wise manner: (1) identify and exclude clear electrographic seizures and status epilepticus (SE), i.e., generalized spike-wave discharges at 3/s or faster; and clearly evolving discharges of any type (rhythmic, periodic, fast activity), whether focal or generalized; (2) exclude clear interictal patterns, i.e., spike-wave discharges, periodic discharges, and rhythmic patterns at 1/s or slower with no evolution, unless accompanied by a clear clinical correlate, which would make them ictal regardless of the frequency; (3) consider any EEG patterns that lie in between the above two categories as being on the ictal-interictal continuum; (4) compare the electrographic pattern of the ictal-incterictal continuum to the normal background and unequivocal seizures (if present) from the same patient; (5) when available, correlate ictal-interictal continuum pattern with other markers of neuronal injury such as neuronal specific enolase (NSE) levels, brain imaging findings, depth electrode recordings, data from microdialysis, intracranial pressure fluctuations, and brain oxygen measurement; and (6) perform a diagnostic trial with preferably a nonsedating antiepileptic drug with the endpoint being both clinical and electrographic improvement. Minimize the use of anesthetics or multiple AEDs unless there is clear supporting evidence from ancillary tests or worsening of the EEG patterns over time, which could indicate possible neuronal injury.
Literature
1.••
Hirsch LJ, LaRoche SM, Gaspard N, Gerard E, Svoronos A, Herman ST, et al. American Clinical Neurophysiology Society’s Standardized Critical Care EEG Terminology: 2012 version. J Clin Neurophysiol. 2013;30:1–27. This study laid the basis for standardized critical care EEG terminology and thereby providing the opportunity for collaborative research.CrossRefPubMed
2.
Young G, Jordan KG, Doig GS. An assessment of nonconvulsive seizures in the intensive care unit using continuous EEG monitoring: an investigation of variable associated with mortality. Neurology. 1996;47:83–9.CrossRefPubMed
3.
Claassen J, Mayer SA, Kowalski RG, Emerson RG, Hirsch LJ. Detection of electrographic seizures with continuous EEG monitoring in critically ill patients. Neurology. 2004;62:1743–8.CrossRefPubMed
4.
Pandian JD, Cascino GD, So EL, Manno E, Fulgham JR. Digital video-electroencephalographic monitoring in the neurological-neurosurgical intensive care unit: clinical features and outcome. Arch Neurol. 2004;61:1090–4.CrossRefPubMed
5.
6.
Chong DJ, Hirsch LJ. Which EEG patterns warrant treatment in the critically ill? Reviewing the evidence for treatment of periodic epileptiform discharges and related patterns. J Clin Neurophysiol. 2005;22:79–91.CrossRefPubMed
7.
8.
9.
Sutter R, Kaplan PW. Electroencephalographic criteria for nonconvulsive status epilepticus: synopsis and comprehensive survey. Epilepsia. 2012;53 Suppl 3:1–51.CrossRefPubMed
10.••
Beniczky S, Hirsch LJ, Kaplan PW, Pressler R, Bauer G, Aurlien H, et al. Unified EEG terminology and criteria for nonconvulsive status epilepticus. Epilepsia. 2013;54 Suppl 6:28–9. First effort towards the development of a unified terminology for non convulsive status epilepticus.CrossRefPubMed
11.
Brophy GM, Bell R, Claassen J, Alldredge B, Bleck TP, Glauser T, et al. Guidelines for the evaluation and management of status epilepticus. Neurocrit Care. 2012;17:3–23.CrossRefPubMed
12.
Jirsch J, Hirsch LJ. Nonconvulsive seizures: developing a rational approach to the diagnosis and management in the critically ill population. Clin Neurophysiol. 2007;118:1660–70.CrossRefPubMed
13.
Gerber PA, Chapman KE, Chung SS, Drees C, Maganti RK, Ng YT, et al. Interobserver agreement in the interpretation of EEG patterns in critically ill adults. J Clin Neurophysiol. 2008;25:241–9.CrossRefPubMed
14.••
Gaspard N, Hirsch LJ, LaRoche SM, Hahn CD, Westover MB, Critical Care EEGMRC. Interrater agreement for critical care EEG terminology. Epilepsia. 2014;55:1366–73. This study validated the critical care EEG terminology, which in turn has helped better identify and understand certain EEG patterns of uncertain significance.CrossRefPubMed
15.•
Gaspard N, Manganas L, Rampal N, Petroff OA, Hirsch LJ. Similarity of lateralized rhythmic delta activity to periodic lateralized epileptiform discharges in critically ill patients. JAMA Neurol. 2013;70:1288–95. This study showed that lateralized rhythmic delta activity in critically ill is associated with high risk of acute seizures.PubMed
16.
Lansberg MG, O'Brien MW, Norbash AM, Moseley ME, Morrell M, Albers GW. MRI abnormalities associated with partial status epilepticus. Neurology. 1999;52:1021–7.CrossRefPubMed
17.
Chu K, Kang DW, Kim JY, Chang KH, Lee SK. Diffusion-weighted magnetic resonance imaging in nonconvulsive status epilepticus. Arch Neurol. 2001;58:993–8.CrossRefPubMed
18.
Kavuk I, Koeppen S, Agelink M, Dorfler A, Limmroth V, Diener HC. Transient MRI abnormalities associated with partial status epilepticus. J Neurol. 2004;251:1156–7.CrossRefPubMed
19.
Szabo K, Poepel A, Pohlmann-Eden B, Hirsch J, Back T, Sedlaczek O, et al. Diffusion-weighted and perfusion MRI demonstrates parenchymal changes in complex partial status epilepticus. Brain. 2005;128:1369–76.CrossRefPubMed
20.
Di Bonaventura C, Bonini F, Fattouch J, Mari F, Petrucci S, Carni M, et al. Diffusion-weighted magnetic resonance imaging in patients with partial status epilepticus. Epilepsia. 2009;50 Suppl 1:45–52.CrossRefPubMed
21.
Katramados AM, Burdette D, Patel SC, Schultz LR, Gaddam S, Mitsias PD. Periictal diffusion abnormalities of the thalamus in partial status epilepticus. Epilepsia. 2009;50:265–75.CrossRefPubMedPubMedCentral
22.
Chatzikonstantinou A, Gass A, Forster A, Hennerici MG, Szabo K. Features of acute DWI abnormalities related to status epilepticus. Epilepsy Res. 2011;97:45–51.CrossRefPubMed
23.
Huang YC, Weng HH, Tsai YT, Huang YC, Hsiao MC, Wu CY, et al. Periictal magnetic resonance imaging in status epilepticus. Epilepsy Res. 2009;86:72–81.CrossRefPubMed
24.
DeGiorgio CM, Correale JD, Gott PS, Ginsburg DL, Bracht KA, Smith T, et al. Serum neuron-specific enolase in human status epilepticus. Neurology. 1995;45:1134–7.CrossRefPubMed
25.
DeGiorgio CM, Gott PS, Rabinowicz AL, Heck CN, Smith TD, Correale JD. Neuron-specific enolase, a marker of acute neuronal injury, is increased in complex partial status epilepticus. Epilepsia. 1996;37:606–9.CrossRefPubMed
26.
DeGiorgio CM, Heck CN, Rabinowicz AL, Gott PS, Smith T, Correale J. Serum neuron-specific enolase in the major subtypes of status epilepticus. Neurology. 1999;52:746–9.CrossRefPubMed
27.
Claassen J. How I treat patients with EEG patterns on the ictal-interictal continuum in the neuro ICU. Neurocrit Care. 2009;11:437–44.CrossRefPubMed
28.
Waziri A, Claassen J, Stuart RM, Arif H, Schmidt JM, Mayer SA, et al. Intracortical electroencephalography in acute brain injury. Ann Neurol. 2009;66:366–77.CrossRefPubMed
29.
Pohlmann-Eden B, Hoch DB, Cochius JI, Chiappa KH. Periodic lateralized epileptiform discharges—a critical review. J Clin Neurophysiol. 1996;13:519–30.CrossRefPubMed
30.
Tellez-Zenteno JF, Pillai SN, Hill MD, Pillay N. Chronic PLEDs with transitional rhythmic discharges (PLEDs-plus) in remote stroke. Epileptic Disord. 2007;9:164–9.PubMed
31.
Westmoreland BF, Klass DW, Sharbrough FW. Chronic periodic lateralized epileptiform discharges. Arch Neurol. 1986;43:494–6.CrossRefPubMed
32.
Hughes JR. Periodic lateralized epileptiform discharges: do they represent an ictal pattern requiring treatment? Epilepsy Behav. 2010;18:162–5.CrossRefPubMed
33.
Terzano MG, Parrino L, Mazzucchi A, Moretti G. Confusional states with periodic lateralized epileptiform discharges (PLEDs): a peculiar epileptic syndrome in the elderly. Epilepsia. 1986;27:446–57.CrossRefPubMed
34.
Handforth A, Cheng JT, Mandelkern MA, Treiman DM. Markedly increased mesiotemporal lobe metabolism in a case with PLEDs: further evidence that PLEDs are a manifestation of partial status epilepticus. Epilepsia. 1994;35:876–81.CrossRefPubMed
35.
Assal F, Papazyan JP, Slosman DO, Jallon P, Goerres GW. SPECT in periodic lateralized epileptiform discharges (PLEDs): a form of partial status epilepticus? Seizure. 2001;10:260–5.CrossRefPubMed
36.
Bozkurt MF, Saygi S, Erbas B. SPECT in a patient with postictal PLEDs: is hyperperfusion evidence of electrical seizure? Clin Electroencephalogr. 2002;33:171–3.CrossRefPubMed
37.•
O’Rourke D, Chen PM, Gaspard N, Foreman B, McClain L, Karakis I, Mahulikar A, Westover MB. Response Rates to Anticonvulsant Trials in Patients with Triphasic-Wave EEG Patterns of Uncertain Significance. Neurocrit Care. 2015. This study discussed the significance and management of the controversial Triphasic—Wave EEG patterns.
38.
Drislane FW, Lopez MR, Blum AS, Schomer DL. Detection and treatment of refractory status epilepticus in the intensive care unit. J Clin Neurophysiol. 2008;25:181–6.CrossRefPubMed
Metadata
Title
Understanding and Managing the Ictal-Interictal Continuum in Neurocritical Care
Authors
Adithya Sivaraju, MD, MHA
Emily J. Gilmore, MD, MS
Publication date
01-02-2016
Publisher
Springer US
Published in
Current Treatment Options in Neurology / Issue 2/2016
Print ISSN: 1092-8480
Electronic ISSN: 1534-3138
DOI
https://doi.org/10.1007/s11940-015-0391-0

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