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Ictal–Interictal Continuum in the Pediatric Intensive Care Unit

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An Invited Commentary to this article was published on 26 April 2024

Abstract

Background

The ictal–interictal continuum (IIC) consists of several electroencephalogram (EEG) patterns that are common in critically ill adults. Studies focused on the IIC are limited in critically ill children and have focused primarily on associations with electrographic seizures (ESs). We report the incidence of the IIC in the pediatric intensive care unit (PICU). We then compare IIC patterns to rhythmic and periodic patterns (RPP) not meeting IIC criteria looking for associations with acute cerebral abnormalities, ES, and in-hospital mortality.

Methods

This was a retrospective review of prospectively collected data for patients admitted to the PICU at Children’s National Hospital from July 2021 to January 2023 with continuous EEG. We excluded patients with known epilepsy and cerebral injury prior to presentation. All patients were screened for RPP. The American Clinical Neurophysiology Society standardized Critical Care EEG terminology for the IIC was applied to each RPP. Associations between IIC and RPP not meeting IIC criteria, with clinical and EEG variables, were calculated using odds ratios (ORs).

Results

Of 201 patients, 21% (42/201) had RPP and 12% (24/201) met IIC criteria. Among patients with an IIC pattern, the median age was 3.4 years (interquartile range (IQR) 0.6–12 years). Sixty-seven percent (16/24) of patients met a single IIC criterion, whereas the remainder met two criteria. ESs were identified in 83% (20/24) of patients and cerebral injury was identified in 96% (23/24) of patients with IIC patterns. When comparing patients with IIC patterns with those with RPP not qualifying as an IIC pattern, both patterns were associated with acute cerebral abnormalities (IIC OR 26 [95% confidence interval {CI} 3.4–197], p = 0.0016 vs. RPP OR 3.5 [95% CI 1.1–11], p = 0.03), however, only the IIC was associated with ES (OR 121 [95% CI 33–451], p < 0.0001) versus RPP (OR 1.3 [0.4–5], p = 0.7).

Conclusions

Rhythmic and periodic patterns and subsequently the IIC are commonly seen in the PICU and carry a high association with cerebral injury. Additionally, the IIC, seen in more than 10% of critically ill children, is associated with ES. The independent impact of RPP and IIC patterns on secondary brain injury and need for treatment of these patterns independent of ES requires further study.

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Funding

This study was not funded.

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Authors and Affiliations

  1. Department of Neurology/Division of Epilepsy and Clinical Neurophysiology, Children’s National Hospital, 111 Michigan Ave NW, Washington, DC, 20010, USA

    Arnold J. Sansevere, Julia S. Keenan, Elizabeth Pickup, Caroline Conley, Katelyn Staso & Dana B. Harrar

  2. Department of Critical Care Medicine, Children’s National Hospital, 111 Michigan Ave NW, Washington, DC, 20010, USA

    Caroline Conley & Katelyn Staso

Authors
  1. Arnold J. Sansevere
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  2. Julia S. Keenan
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  3. Elizabeth Pickup
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  4. Caroline Conley
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  5. Katelyn Staso
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  6. Dana B. Harrar
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Contributions

Dr. Sansevere participated in conception, study design, data collection, data analysis, manuscript preparation, editing and submission. As the primary author Dr. Sansevere takes full responsibility for all aspects of this work. Ms. Keenan participated in conception, study design, data collection, data analysis, manuscript preparation, editing, and approval. Dr. Pickup participated in study design, data collection, manuscript preparation editing, and approval. Dr. Conley participated in study design, data collection, manuscript preparation, editing, and approval. Ms. Staso participated in study design, data collection, manuscript preparation editing, and approval. Dr. Harrar participated in conception, study design, data collection, manuscript preparation, editing, and approval. The final manuscript presented was edited and approved by all authors.

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Correspondence to Arnold J. Sansevere.

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This is an institution review board–approved study at our institution, and it has been assigned the following identification number: Pro00015473.

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Sansevere, A.J., Keenan, J.S., Pickup, E. et al. Ictal–Interictal Continuum in the Pediatric Intensive Care Unit. Neurocrit Care (2024). https://doi.org/10.1007/s12028-024-01978-4

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