Kendall B. Nash

Predictors of outcome in perinatal arterial stroke: A population-based study

Some infants with perinatal arterial ischemic stroke (PAS) experience development of cerebral palsy (CP), epilepsy, and cognitive impairment, whereas others have a normal outcome. Previous prognostic studies rarely have included all diagnosed cases of PAS within a population. Among 199,176 infants born within Kaiser Permanente from 1997 to 2002, we electronically identified head imaging reports and physician diagnoses suggesting stroke. The diagnosis of PAS was confirmed by review of brain imaging and medical records. Presentation of PAS was considered delayed if symptoms were only noted after 28 days. Outcomes were determined by chart review. Of 40 infants with PAS, 36 were observed over 12 months. Abnormal outcomes included CP (58%), epilepsy (39%), language delay (25%), and behavioral abnormalities (22%). A delayed presentation was associated with increased risk for CP (relative risk [RR], 2.2; 95% confidence interval [CI], 1.2–4.2). Radiological predictors of CP included large stroke size (RR, 2.0; 95% CI, 1.2–3.2) and injury to Brocas area (RR, 2.5; 95% CI, 1.3–5.0), internal capsule (RR, 2.2; 95% CI, 1.1–4.4), Wernickes area (RR, 2.0; 95% CI, 1.1–3.8), or basal ganglia (RR, 1.9; 95% CI, 1.1–3.3). Among infants with PAS, specific radiological findings and a lack of symptoms in the newborn period are associated with increased risk for CP. Ann Neurol 2005

Video-EEG monitoring in newborns with hypoxic-ischemic encephalopathy treated with hypothermia

Background: Therapeutic hypothermia (TH) is becoming standard of care in newborns with hypoxic-ischemic encephalopathy (HIE). The prognostic value of the EEG and the incidence of seizures during TH are uncertain. Objective: To describe evolution of EEG background and incidence of seizures during TH, and to identify EEG patterns predictive for MRI brain injury. Methods: A total of 41 newborns with HIE underwent TH. Continuous video-EEG was performed during hypothermia and rewarming. EEG background and seizures were reported in a standardized manner. Newborns underwent MRI after rewarming. Sensitivity and specificity of EEG background for moderate to severe MRI brain injury was assessed at 6-hour intervals during TH and rewarming. Results: EEG background improved in 49%, remained the same in 38%, and worsened in 13%. A normal EEG had a specificity of 100% upon initiation of monitoring and 93% at later time points. Burst suppression and extremely low voltage patterns held the greatest prognostic value only after 24 hours of monitoring, with a specificity of 81% at the beginning of cooling and 100% at later time points. A discontinuous pattern was not associated with adverse outcome in most patients (73%). Electrographic seizures occurred in 34% (14/41), and 10% (4/41) developed status epilepticus. Seizures had a clinical correlate in 57% (8/14) and were subclinical in 43% (6/14). Conclusions: Continuous video-EEG monitoring in newborns with HIE undergoing TH provides prognostic information about early MRI outcome and accurately identifies electrographic seizures, nearly half of which are subclinical.

Electrographic seizures in pediatric ICU patients Cohort study of risk factors and mortality

Objectives: We aimed to determine the incidence of electrographic seizures in children in the pediatric intensive care unit who underwent EEG monitoring, risk factors for electrographic seizures, and whether electrographic seizures were associated with increased odds of mortality. Methods: Eleven sites in North America retrospectively reviewed a total of 550 consecutive children in pediatric intensive care units who underwent EEG monitoring. We collected data on demographics, diagnoses, clinical seizures, mental status at EEG onset, EEG background, interictal epileptiform discharges, electrographic seizures, intensive care unit length of stay, and in-hospital mortality. Results: Electrographic seizures occurred in 162 of 550 subjects (30%), of which 61 subjects (38%) had electrographic status epilepticus. Electrographic seizures were exclusively subclinical in 59 of 162 subjects (36%). A multivariable logistic regression model showed that independent risk factors for electrographic seizures included younger age, clinical seizures prior to EEG monitoring, an abnormal initial EEG background, interictal epileptiform discharges, and a diagnosis of epilepsy. Subjects with electrographic status epilepticus had greater odds of in-hospital death, even after adjusting for EEG background and neurologic diagnosis category. Conclusions: Electrographic seizures are common among children in the pediatric intensive care unit, particularly those with specific risk factors. Electrographic status epilepticus occurs in more than one-third of children with electrographic seizures and is associated with higher in-hospital mortality.

Seizures and magnetic resonance imaging-detected brain injury in newborns cooled for hypoxic-ischemic encephalopathy.

OBJECTIVE To describe the association between electrographically detected seizures and brain injury evaluated by magnetic resonance imaging in newborns treated with hypothermia. STUDY DESIGN A total of 56 newborns treated with hypothermia were monitored using video electroencephalography through cooling and rewarming, and then imaged at a median of 5 days. The electroencephalograms were reviewed for indications of seizure and status epilepticus. Moderate-severe injury detected on magnetic resonance imaging was measured using a classification scheme similar to one predicting abnormal outcome in an analogous population. RESULTS Seizures were recorded in 17 newborns (30%), 5 with status epilepticus. Moderate-severe injury was more common in newborns with seizures (relative risk, 2.9; 95% CI, 1.2-4.5; P=.02), and was present in all 5 newborns with status epilepticus. Newborns with moderate-severe injury had seizures that were multifocal and of later onset, and they were more likely to experience recurrent seizures after treatment with 20 mg/kg phenobarbital. Newborns with only subclinical seizures were as likely to have injury as those with seizures with a clinical correlate (57% vs 60%). CONCLUSION Seizures represent a risk factor for brain injury in the setting of therapeutic hypothermia, especially in neonates with status epilepticus, multifocal-onset seizures, and a need for multiple medications. However, 40% of our neonates were spared from brain injury, suggesting that the outcome after seizures is not uniformly poor in children treated with therapeutic hypothermia.

Electrographic seizures after convulsive status epilepticus in children and young adults: a retrospective multicenter study.

OBJECTIVE To describe the prevalence, characteristics, and predictors of electrographic seizures after convulsive status epilepticus (CSE). STUDY DESIGN This was a multicenter retrospective study in which we describe clinical and electroencephalographic (EEG) features of children (1 month to 21 years) with CSE who underwent continuous EEG monitoring. RESULTS Ninety-eight children (53 males) with CSE (median age of 5 years) underwent subsequent continuous EEG monitoring after CSE. Electrographic seizures (with or without clinical correlate) were identified in 32 subjects (33%). Eleven subjects (34.4%) had electrographic-only seizures, 17 subjects (53.1%) had electroclinical seizures, and 4 subjects (12.5%) had an unknown clinical correlate. Of the 32 subjects with electrographic seizures, 15 subjects (46.9%) had electrographic status epilepticus. Factors associated with the occurrence of electrographic seizures after CSE were a previous diagnosis of epilepsy (P = .029) and the presence of interictal epileptiform discharges (P < .0005). The median (p25-p75) duration of stay in the pediatric intensive care unit was longer for children with electrographic seizures than for children without electrographic seizures (9.5 [3-22.5] vs 2 [2-5] days, Wilcoxon test, Z = 3.916, P = .0001). Four children (4.1%) died before leaving the hospital, and we could not identify a relationship between death and the presence or absence of electrographic seizures. CONCLUSIONS After CSE, one-third of children who underwent EEG monitoring experienced electrographic seizures, and among these, one-third experienced entirely electrographic-only seizures. A previous diagnosis of epilepsy and the presence of interictal epileptiform discharges were risk factors for electrographic seizures.

Electroencephalography monitoring in critically ill children: Current practice and implications for future study design

Survey data indicate that continuous electroencephalography (EEG) (CEEG) monitoring is used with increasing frequency to identify electrographic seizures in critically ill children, but studies of current CEEG practice have not been conducted. We aimed to describe the clinical utilization of CEEG in critically ill children at tertiary care hospitals with a particular focus on variables essential for designing feasible prospective multicenter studies evaluating the impact of electrographic seizures on outcome.

Focal seizures in children with anti-NMDA receptor antibody encephalitis.

OBJECTIVE We investigated the electroclinical features of seizures occurring in children with anti-NMDA receptor antibody encephalitis. METHODS Clinical features and video EEG recordings were analyzed from pediatric patients with anti-NMDA receptor antibody encephalitis at our center over a six year period. RESULTS We identified eight pediatric patients with anti-NMDA receptor antibody encephalitis. Video EEG captured multiple focal seizures in four patients. Ictal onset in all four patients consisted of a focal rhythmic sharpened 6-12Hz activity that subsequently spread to one or both hemispheres. When there was a clinical correlate, seizure semiology was limb posturing with or without dyscognitive features. While background abnormalities were noted at presentation in three cases, the initial EEG background was normal in five, including three patients presenting with seizures. The EEG background deteriorated with clinical progression. CONCLUSIONS Focal seizures are common in pediatric patients with anti-NMDA receptor antibody encephalitis and have a characteristic ictal onset pattern. Anti-NMDA receptor antibody encephalitis should be considered in the differential diagnosis of a child presenting with new onset focal seizures, irrespective of the EEG background, especially if accompanied by dyskinesia, psychiatric symptoms or impaired cognition.

Electroencephalographic Monitoring in the Pediatric Intensive Care Unit

Continuous electroencephalographic (CEEG) monitoring is used with increasing frequency in critically ill children to provide insight into brain function and to identify electrographic seizures. CEEG monitoring use often impacts clinical management, most often by identifying electrographic seizures and status epilepticus. Most electrographic seizures have no clinical correlate, and thus would not be identified without CEEG monitoring. There are increasing data showing that electrographic seizures and electrographic status epilepticus are associated with worse outcome. Seizure identification efficiency may be improved by further development of quantitative electroencephalography trends. This review describes the clinical impact of CEEG data, the epidemiology of electrographic seizures and status epilepticus, the impact of electrographic seizures on outcome, the utility of quantitative electroencephalographic trends for seizure identification, and practical considerations regarding CEEG monitoring.

Development and validation of a seizure prediction model in critically ill children

PURPOSE Electrographic seizures are common in encephalopathic critically ill children, but identification requires continuous EEG monitoring (CEEG). Development of a seizure prediction model would enable more efficient use of limited CEEG resources. We aimed to develop and validate a seizure prediction model for use among encephalopathic critically ill children. METHOD We developed a seizure prediction model using a retrospectively acquired multi-center database of children with acute encephalopathy without an epilepsy diagnosis, who underwent clinically indicated CEEG. We performed model validation using a separate prospectively acquired single center database. Predictor variables were chosen to be readily available to clinicians prior to the onset of CEEG and included: age, etiology category, clinical seizures prior to CEEG, initial EEG background category, and inter-ictal discharge category. RESULTS The model has fair to good discrimination ability and overall performance. At the optimal cut-off point in the validation dataset, the model has a sensitivity of 59% and a specificity of 81%. Varied cut-off points could be chosen to optimize sensitivity or specificity depending on available CEEG resources. CONCLUSION Despite inherent variability between centers, a model developed using multi-center CEEG data and few readily available variables could guide the use of limited CEEG resources when applied at a single center. Depending on CEEG resources, centers could choose lower cut-off points to maximize identification of all patients with seizures (but with more patients monitored) or higher cut-off points to reduce resource utilization by reducing monitoring of lower risk patients (but with failure to identify some patients with seizures).

Should there be pediatric neurohospitalists

Hospitalist medicine has gown rapidly over the past decade in response to increasing complexity of hospitalized patients, financial pressures, and a national call for improved quality and safety outcomes. An adult neurohospitalist model of care has recently emerged to address these factors and the need for inpatient neurologists who offer expertise and immediate availability for emergent neurologic conditions such as acute stroke and status epilepticus. Similarly, hospitalized children with acute neurologic disorders require a uniquely high level of care, which increasingly cannot be delivered by pediatric neurologists with busy outpatient practices or by pediatric hospitalists without specialized training. This perspective explores the concept of a pediatric neurohospitalist model of care, including the potential impact on quality of care, hospitalization costs, and education.