Predictors of nonconvulsive seizures among critically ill children

Abstract

Summary Purpose: Continuous electroencephalography (EEG) monitoring is a valuable tool for the detection of seizures among critically ill children, in particular when these seizures occur without clinical signs: termed nonconvulsive seizures. Continuous EEG monitoring is a limited resource in many centers. We sought to identify which critically ill children most frequently experience nonconvulsive seizures, and thus may particularly benefit from continuous EEG monitoring. Methods: Single‐center review was undertaken of consecutive diagnostic continuous EEG (cEEG) recordings performed in our pediatric and neonatal intensive care units (ICUs). We examined the indications for monitoring, the clinical characteristics of monitored patients, the occurrence and timing of seizures, and clinical and EEG characteristics associated with nonconvulsive seizures. Key Findings: One hundred twenty‐one patients underwent diagnostic continuous EEG monitoring, for a mean duration of 26 h. Seizures were detected in 32% of these patients, of which 90% experienced some nonconvulsive seizures, and 72% experienced exclusively nonconvulsive seizures. Patients with nonconvulsive seizures had significantly greater odds of having acute epilepsy, acute structural brain injury, prior in‐hospital convulsive seizures, and the presence of interictal epileptiform abnormalities on EEG. Significance: Seizures are common among critically ill children undergoing diagnostic cEEG monitoring. The great majority of these seizures are nonconvulsive, requiring EEG for their detection. Predictors of nonconvulsive seizures include acute epilepsy, acute structural brain injury, prior in‐hospital convulsive seizures, and interictal epileptiform abnormalities on EEG. These findings can help inform future allocation of limited cEEG monitoring resources to those patients at greatest risk for nonconvulsive seizures.

Electrographic seizures in pediatric ICU patients

“…[1][2][3][4][5][6][7][8][9][10][11][12] The majority of electrographic seizures were not accompanied by any clinical signs, 1,3,8,[10][11][12][13][14] even in nonparalyzed patients. 1,14 Therefore, accurate seizure identification requires CEEG.…”

“…Reported clinical risk factors for electrographic seizures in children include younger age, 1,10 preceding convulsive status epilepticus 10 or clinically overt seizures, 11,13 and structural brain injury, 11,13 including traumatic brain injury 10 and hypoxic-ischemic brain injury after cardiac arrest. 9 Reported electrographic risk factors include epileptiform discharges, 10,13 periodic epileptiform discharges, 3 and lack of background reactivity. 3 Most of these studies involved etiologically heterogeneous cohorts with only a small number of subjects with each etiology.…”

Status Epilepticus in the PICU: Quieting the Storm

“…The majority of these studies are retrospective, and have found either NCS or NCSE in 16-39 % of patients, and NCSE in 0-35 % of patients [11][12][13][14][15][16][17]. In addition, there have been three recent prospective studies, for which either NCS or NCSE was diagnosed in critically ill children using [19], and 19 [20 • ].…”

“…Some reported risk factors for NCS or NCSE include younger age (\2 years) [12,17,19,20 • ], and a clinical seizure prior to EEG monitoring [11,14,[16][17][18][19]. In the series from Abend et al [20 • ] for every 1-year increase in age, there was a 7 % decrease in the odds of seizure occurrence.…”

Les explorations neurophysiologiques chez l’enfant cérébrolésé : quand, comment ?

“…Dans les séries adultes et pédiatriques rétrospectives, c'est-à-dire dans des populations avec biais de sélection certain, les taux de crises purement électriques variaient de 16 à 48 % [11][12][13]. L'étude australienne montrait également que la plupart des suspicions cliniques de crises n'étaient en réalité pas des crises convulsives (22 % seulement).…”