Ictal-interictal Continuum, Neither Interictal nor Ictal.pptx

Ictal-interictal Continuum, Neither Interictal nor Ictal.pptx

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  Ictal-interictal Continuum ADE WIJAYA,MD – MARCH 2025
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  Introduction • The conceptof ictal-interictal continuum (IIC) was first coined by Pohlmann- Eden et al. in 1996. • The term “IIC” is synonymous with “possible electrographic status epilepticus” if it lasts at least 10min or occupies at least 20% of any hour of recording, per the ACNS terminology Cobb W, Hill D. Electroencephalogram in subacute progressive encephalitis. Brain. 1950;73:392–404. Hirsch LJ, Fong MWK, Leitinger M, LaRoche SM, Beniczky S, Abend NS, et al. American clinical neurophysiology Society's standardized critical care EEG terminology: 2021 version. J Clin Neurophysiol. 2021;38(1):1–29.
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  IIC Definition by theAmerican Clinical Neurophysiology Society • 1. Any PD or SW pattern that averages >1.0Hz but ≤2.5Hz over 10 s (>10 but ≤25 discharges in 10 s); OR • 2. Any PD or SW pattern that averages ≥.5Hz and≤1Hz over 10 s (≥5 and≤10 discharges in 10 s), and has a plus modifier or fluctuation; OR • 3. Any lateralized RDA averaging >1Hz for at least 10 s (at least 10 waves in 10 s) with a plus modifier or fluctuation; AND • 4. Does not qualify as an ESz or ESE Hirsch LJ, Fong MWK, Leitinger M, LaRoche SM, Beniczky S, Abend NS, et al. American clinical neurophysiology Society's standardized critical care EEG terminology: 2021 version. J Clin Neurophysiol. 2021;38(1):1–29.
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  EEG patterns ofictal-interictal continuum • Lateralized periodic discharges • Generalized periodic discharges • Bilateral independent periodic discharges • Lateralized rhythmic delta activity • Stimulus-induced rhythmic, periodic or ictal discharges • Brief potentially ictal rhythmic discharges Tao, J. X., Qin, X., & Wang, Q. (2020). Ictal-interictal continuum: a review of recent advancements. Acta Epileptologica, 2, 1-10.
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  Risk stratification ofIIC patterns associated with seizures • (1) segregate IIC patterns from NCS and NCSE; • (2) assess the risk of seizures associated with IIC patterns; • (3) determine the ictal nature of IIC patterns; • (4) assess the long term risk of developing chronic epilepsy Tao, J. X., Qin, X., & Wang, Q. (2020). Ictal-interictal continuum: a review of recent advancements. Acta Epileptologica, 2, 1-10.
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  Modified Salzburg Consensusfor NCSE Kubota, Y., Nakamoto, H., Egawa, S., & Kawamata, T. (2018). Continuous EEG monitoring in ICU. Journal of Intensive Care, 6, 1-8. Patterns occurring at a frequency of 1–2.5 Hz are considered ictal-interictal continuum Tao, J. X., Qin, X., & Wang, Q. (2020). Ictal-interictal continuum: a review of recent advancements. Acta Epileptologica, 2, 1-10.
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  Assess the riskof seizures associated with IIC patterns • The increased risk of seizures associated with IIC patterns has been well- described. • GRDA was commonly not associated with an increased seizure risk • “LPD+ Rhythmicity” was associated with the highest odds for developing seizures and status epilepticus. • “LPD+ Fast activity” were also highly associated with ictal activity • LPDs bearing blunt morphology were not associated with ictal activity Newey CR, Sahota P, Hantus S. Electrographic features of lateralized periodic discharges stratify risk in the interictal-Ictal continuum. J Clin Neurophysiol. 2017;34:365–9. Rodriguez Ruiz A, Vlachy J, Lee JW, et al. Association of periodic and rhythmic electroencephalographic patterns with Seizures in critically ill patients. JAMA Neurol. 2017;74:181–8.
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  IIC patterns beingpotentially ictal patterns • LPDs with negative clinical correlates are potentially ictal. • IIC patterns may be associated with known imaging markers of electrographic seizures. • IIC patterns may be associated with metabolic biomarkers of neuronal injury. • IIC patterns on scalp EEG can be associated with intracranial seizures on intracranial recordings using depth EEG. Tao, J. X., Qin, X., & Wang, Q. (2020). Ictal-interictal continuum: a review of recent advancements. Acta Epileptologica, 2, 1-10.
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  Risk of IICpatterns associated with epilepsy • The risk of epilepsy associated with IIC patterns has been reported in several small case studies. • Epilepsy was developed in 48.5% of patients with LPDs and electrographic seizures during a mean follow-up duration of 11.9 months • Among the different acute brain injury subtypes, IIC patterns with acute TBI were highly associated with posttraumatic epilepsy • In patients with ischemic stroke, LPDs and sporadic epileptiform discharges are associated with higher risk of stroke related epilepsy • Overall 10 to 60% patients with LPDs go on to develop chronic epilepsy after hospital discharge Tao, J. X., Qin, X., & Wang, Q. (2020). Ictal-interictal continuum: a review of recent advancements. Acta Epileptologica, 2, 1-10.
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  Treatment • Treat non-convulsiveseizures • Most of IIC patterns (other than GRDA) are highly associated with increased risk of seizures, particularly when they are > 2.0 Hz and associated with “plus” features. It is critical that patients with IIC patterns should be monitored with continuous EEG for the surveillance of NCS and NCSE. Prophylactic treatment with non-sedating anti-seizure medications (ASM) such as Levetiracetam and Lacosamide may be considered [51]. The therapeutic goal of prophylaxis is to prevent IIC patterns from evolving into seizures Hirsch LJ, LaRoche SM, Gaspard N, et al. American clinical neurophysiology Society's standardized critical care EEG terminology: 2012 version. J Clin Neurophysiol. 2013;30:1–27. Osman GM, Araujo DF, Maciel CB. Ictal Interictal continuum patterns. Curr Treat Options Neurol. 2018;20:15
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  Treatment • When thetreatment decision is uncertain, a trial of benzodiazepine or a loading dose of ASM may be empirically performed. If there are both immediate electrographic and clinical improvements, the trial is considered positive and further ASM treatment is warranted for pattern suppression • It is not unreasonable to discontinue the prophylactic ASM treatment at the time of hospital discharge. For patients with IIC patterns and seizures during ICU admission, ASM may be continued for 6–12 months. For IIC patients with preexisting epilepsy and late onset seizures, long-term ASM treatment are often necessary Sivaraju A, Gilmore EJ. Understanding and managing the Ictal-Interictal continuum in Neurocritical care. Curr Treat Options Neurol. 2016;18:8. 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 Herlopian A, Struck AF, Rosenthal E, et al. Neuroimaging correlates of periodic discharges. J Clin Neurophysiol. 2018;35:279 –94.
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  Summary • Ictal-interictal continuumpresents a challenging electrophysiological and clinical conundrum in the management of critically ill patients. • There are no evidence-based guidelines on how to treat the patients with IIC patterns. • Treatment should be based on the patient’s overall clinical picture and the seizure risk associated with IIC patterns. • Prophylactic treatment with non-sedating ASM may be considered to mitigate the seizure risk for IIC patterns. • When the treatment decision is uncertain, benzodiazepine trial or a loading dose of ASM can be empirically performed. If there are both electrographic and clinical improvements, further ASM treatment is warranted • Anesthetic agents may be considered when conventional ASM are not effective. • Treatment decision should weigh the potential neuronal injury of IIC patterns against the iatrogenic complications of ASM • Treatment of underlying etiology is paramount in critically ill patients with IIC patterns.
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  THANK YOU