Subclinical early posttraumatic seizures detected by continuous EEG monitoring in a consecutive pediatric cohort

Abstract

Summary Purpose Traumatic brain injury (TBI) is an important cause of morbidity and mortality in children and early post-traumatic seizures (EPTS) are a contributing factor to ongoing acute damage. Continuous video EEG monitoring (cEEG) was utilized to assess the burden of clinical and electrographic EPTS. Methods Eighty-seven consecutive, unselected (mild – severe), acute TBI patients requiring pediatric intensive care unit (PICU) admission at 2 academic centers were prospectively monitored with cEEG per established clinical TBI protocols. Clinical and subclinical seizures and status epilepticus (SE, clinical and subclinical) were assessed for their relation to clinical risk factors and short-term outcome measures. Key findings Of all patients, 42.5% (37/87) had seizures. Younger age (p=0.002) and mechanism (abusive head trauma - AHT, p<0.001) were significant risk factors. Subclinical seizures occurred in 16.1% (14/87), 6 of whom had only subclinical seizures. Risk factors for subclinical seizures included: younger age (p<0.001), AHT (p<0.001) and intraaxial bleed (p<0.001). Status Epilepticus (SE) occurred in 18.4% (16/87) with risk factors including: younger age (p<0.001), AHT (p<0.001), and intraaxial bleed (p=0.002). Subclinical SE was detected in 13.8% (12/87) with significant risk factors including: younger age (p<0.001), AHT (p=0.001), and intraaxial bleed (p=0.004). Subclinical seizures were associated with lower discharge KOSCHI score (p=0.002). SE and subclinical SE were associated with increased hospital length of stay (p=0.017 and p=0.041 respectively) and lower hospital discharge KOSCHI (p=0.007 and p=0.040 respectively). Significance cEEG monitoring significantly improves detection of seizures/SE and is the only way to detect subclinical seizures/SE. cEEG may be indicated after pediatric TBI, particularly in younger children, AHT cases, and those with intraaxial blood on CT.

Incidence of seizures on continuous EEG monitoring following traumatic brain injury in children

“…2,6,13,15,17,19 Half of our older cohort with seizures had only clinical seizures, which could presumably be recognized without cEEG, whereas only 5% of the group had any subclinical seizures. The older group also had a lower seizure burden as evidenced by the low rate of status epilepticus and the fact that half of these patients had 1 or 2 seizures.…”

“…The routine use of prolonged video EEG in pediatric patients with TBI has been explored in 1 other study (which included 27 of the patients in this cohort). 2 Arndt et al reviewed 87 pediatric patients with TBI admitted to the ICU and monitored with cEEG for a minimum of 48 hours. They identified seizures in 43% of their cohort; 38% of those with seizures had subclinical seizures, and 43% had status epilepticus (defined as a single seizure > 15 minutes in duration or > 3 seizures per hour).…”

“…Severity of injury did not correlate with seizures. 2 Arango and colleagues prospectively collected clinical and electrographic seizure data on 270 pediatric patients with severe TBI. Continuous EEG was sporadically used.…”

“…2,6,13,15,17,19 Continuous electroencephalography (cEEG) is the only test to definitively diagnose subclinical seizures. It additionally offers a continuous record of any seizure activity that may have otherwise gone unwitnessed.…”

Pathophysiology and Treatment of Severe Traumatic Brain Injuries in Children

“…Initially, nurses should monitor vital signs each hour or more frequently depending on the child's condition and continue to monitor the child's pain level (Hockenberry & Wilson, 2007) Antiseizure prophylaxis-Prophylactic treatment with phenytoin may be considered to reduce the incidence of early posttraumatic seizures (PTS) (Kochanek et al, 2012). Early PTS are witnessed clinical seizures or abnormal trace recordings on EEG within the first 7 days following the traumatic event (Arango et al, 2012) with about 44% of children having at least one seizure (Arndt et al, 2013). Risk factors associated with any type of PTS are young age, type of trauma (abusive head trauma), epidural hematoma (Arango et al, 2012), and skull fracture (Arndt et al, 2013).…”