Early Anatomical Injury Patterns Predict Epilepsy in Head Cooled Neonates With Hypoxic-Ischemic Encephalopathy

MRI predictors of long-term outcomes of neonatal hypoxic ischaemic encephalopathy: a primer for radiologists

This review aims to serve as a foundational resource for general radiologists, enhancing their understanding of the role of Magnetic Resonance Imaging (MRI) in early prognostication for newborns diagnosed with hypoxic ischaemic encephalopathy (HIE). The article explores the application of MRI as a predictive instrument for determining long-term outcomes in newborns affected by HIE. With HIE constituting a leading cause of neonatal mortality and severe long-term neurodevelopmental impairments, early identification of prognostic indicators is crucial for timely intervention and optimal clinical management. We examine current literature and recent advancements to provide an in-depth overview of MRI predictors, encompassing brain injury patterns, injury scoring systems, spectroscopy, and diffusion imaging. The potential of these MRI biomarkers in predicting long-term neurodevelopmental outcomes and the probability of epilepsy is also discussed.

Neonatal brain MRI and short-term outcomes after acute provoked seizures

OBJECTIVE

We investigated how diagnosis and injury location on neonatal brain MRI following onset of acute provoked seizures was associated with short term outcome.

STUDY DESIGN

A multicenter cohort of neonates with acute provoked seizures enrolled in the Neonatal Seizure Registry. MRIs were centrally evaluated by a neuroradiologist for location of injury and radiologic diagnosis. Clinical outcomes were determined by chart review. Multivariate logistic regression was used to examine the association between MRI findings and outcomes.

RESULTS

Among 236 newborns with MRI at median age 4 days (IQR 3-8), 91% had abnormal MRI. Radiologic diagnoses of intracranial hemorrhage (OR 3.2 [1.6-6.5], p < 0.001) and hypoxic-ischemic encephalopathy (OR 2.7 [1.4-5.4], p < 0.003) were associated with high seizure burden. Radiologic signs of intracranial infection were associated with abnormal neurologic examination at discharge (OR 3.9 [1.3-11.6], p < 0.01).

CONCLUSION

Findings on initial MRI can help with expectant counseling on short-term outcomes following acute provoked neonatal seizures.

Genetic Polymorphisms, Gene-Gene Interactions and Neurologic Sequelae at Two Years Follow-Up in Newborns with Hypoxic-Ischemic Encephalopathy Treated with Hypothermia

Inflammation and oxidative stress after hypoxic-ischemic brain injury may be modified by genetic variability in addition to therapeutic hypothermia. The aim of our study was to evaluate the association between the polymorphisms in genes of antioxidant and inflammatory pathways in newborns treated with therapeutic hypothermia and the development of epilepsy or CP at two years follow-up. The DNA of 55 subjects was isolated from buccal swabs. Genotyping using competitive allele-specific PCR was performed for polymorphisms in antioxidant (SOD2 rs4880, CAT rs1001179, GPX1 rs1050450) and inflammatory (NLRP3 rs35829419, CARD8 rs2043211, IL1B rs1143623, IL1B rs16944, IL1B rs10716 76, TNF rs1800629) pathways. Polymorphic CARD8 rs2043211 T allele was less frequent in patients with epilepsy, but the association was not statistically significant. The interaction between CARD8 rs2043211 and IL1B rs16944 was associated with epilepsy after HIE: CARD8 rs2043211 was associated with lower epilepsy risk, but only in carriers of two normal IL1B rs16944 alleles (OR_adj = 0.03 95% CI = 0.00–0.55; p_adj = 0.019). Additionally, IL1B rs16944 was associated with higher epilepsy risk only in carriers of at least one polymorphic CARD8 rs2043211 (OR_adj = 13.33 95% CI = 1.07–166.37; p_adj = 0.044). Our results suggest that gene–gene interaction in inflammation pathways might contribute to the severity of brain injury in newborns with HIE treated with therapeutic hypothermia.

Management of seizures in neonates with neonatal encephalopathy treated with hypothermia

Neonatal encephalopathy (NE) is the most common etiology of acute neonatal seizures - about half of neonates treated with therapeutic hypothermia for NE have EEG-confirmed seizures. These seizures are best identified with continuous EEG monitoring, as clinical diagnosis leads to under-diagnosis of subclinical seizures and over-treatment of events that are not seizures. High seizure burden, especially status epilepticus, is thought to augment brain injury. Treatment, therefore, is aimed at minimizing seizure burden. Phenobarbital remains the mainstay of treatment, as it is more effective than levetiracetam and easier to administer than fosphenytoin. Emerging evidence suggests that, for many neonates, it is safe to discontinue the phenobarbital after acute seizures resolve and prior to hospital discharge.

ACR Appropriateness Criteria® Seizures-Child

In children, seizures represent an extremely heterogeneous group of medical conditions ranging from benign cases, such as a simple febrile seizure, to life-threatening situations, such as status epilepticus. Underlying causes of seizures also represent a wide range of pathologies from idiopathic cases, usually genetic, to a variety of acute and chronic intracranial or systemic abnormalities. This document discusses appropriate utilization of neuroimaging tests in a child with seizures. The clinical scenarios in this document take into consideration different circumstances at the time of a child's presentation including the patient's age, precipitating event (if any), and clinical and electroencephalogram findings and include neonatal seizures, simple and complex febrile seizures, post-traumatic seizures, focal seizures, primary generalized seizures in a neurologically normal child, and generalized seizures in neurologically abnormal child. This practical approach aims to guide clinicians in clinical decision-making and to help identify efficient and appropriate imaging workup. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Risk for infantile spasms after acute symptomatic neonatal seizures

OBJECTIVE

Infantile spasms (IS) is a severe epilepsy in early childhood. Early treatment of IS provides the best chance of seizure remission and favorable developmental outcome. We aimed to develop a prediction rule to accurately predict which neonates with acute symptomatic seizures will develop IS.

METHODS

We used data from the Neonatal Seizure Registry, a prospective, multicenter cohort of infants with acute symptomatic neonatal seizures born from July 2015 to March 2018. Neonates with acute symptomatic seizures who received clinical electroencephalography (EEG) and magnetic resonance imaging (MRI) and were younger than 2 years of age at the time of enrollment were included. We evaluated the association of neonatal EEG, MRI, and clinical factors with subsequent IS using bivariate analysis and best subsets logistic regression. We selected a final model through a consensus process that balanced statistical significance with clinical relevance.

RESULTS

IS developed in 12 of 204 infants (6%). Multiple potential predictors were associated with IS, including Apgar scores, EEG features, seizure characteristics, MRI abnormalities, and clinical status at hospital discharge. The final model included three risk factors: (a) severely abnormal EEG or ≥3 days with seizures recorded on EEG, (b) deep gray or brainstem injury on MRI, and (c) abnormal tone on discharge exam. The stratified risk of IS was the following: no factors 0% (0/82, 95% confidence interval [CI] 0%-4%), one or two factors 4% (4/108, 95% CI 1%-9%), and all three factors 57% (8/14, 95% CI 29%-83%).

SIGNIFICANCE

IS risk after acute symptomatic neonatal seizures can be stratified using commonly available clinical data. No child without risk factors, vs >50% of those with all three factors, developed IS. This risk prediction rule may be valuable for clinical counseling as well as for selecting participants for clinical trials to prevent post-neonatal epilepsy. This tailored approach may lead to earlier diagnosis and treatment and improve outcomes for a devastating early life epilepsy.

Neurodevelopmental outcomes at 9-14 months gestational age after treatment of neonatal seizures due to brain injury

PURPOSE

Infants with brain injury are susceptible to developmental delays. Survivors of neonatal seizures are at risk for developmental delay, epilepsy, and further neurological comorbidities. Despite advances in neonatal critical care, the prevalence of adverse long-term outcomes and seizure recurrence remains unchanged. Our goal is to determine if early treatment of neonatal seizures with phenobarbital or levetiracetam is associated with worse neurodevelopmental outcomes in brain-injured infants.

METHODS

We conducted a retrospective cohort study of 119 infants admitted between 2013 and 2017 who were at risk for developmental delay and assessed in our clinic. We compared brain injury infants with neonatal seizures to brain injury infants without neonatal seizures using Bayley scores (BSID III) at 9-14 months gestational age. A comparison of Bayley scores between those exposed to phenobarbital and levetiracetam was conducted.

RESULTS

Twenty-two children with neonatal seizures scored lower than 53 children without seizures in all domains with significant values in composite scores for cognitive function (p = 0.003) and language (p = 0.031). We found no difference in scores at 9-14 months between infants exposed to phenobarbital versus levetiracetam.

CONCLUSIONS

Our results suggest that in infants with brain injury, the occurrence of neonatal seizures has an adverse effect on neurodevelopmental outcomes. The choice of antiseizure medication may not play a significant role in their outcomes.

Brain cooling reduces the risk of postneonatal epilepsy in newborns affected by moderate to severe hypoxic-ischemic encephalopathy

BACKGROUND

Neonatal hypoxic-ischemic encephalopathy is still a significant cause of neonatal death and neurodevelopmental disabilities, such as cerebral palsy, mental delay, and epilepsy. After the introduction of therapeutic hypothermia, the prognosis of hypoxic-ischemic encephalopathy has improved, with reduction of death and disabilities. However, few studies evaluated whether hypothermia affects rate and severity of postneonatal epilepsy. We evaluated rates, characteristics and prognostic markers of postneonatal epilepsy in infants with moderate to severe hypoxic-ischemic encephalopathy treated or not with therapeutic hypothermia.

METHODS

We analyzed clinical data, EEG recordings, cerebral Magnetic Resonance Imaging (MRI) and outcome in 23 cooled and 26 non-cooled asphyxiated neonates (≥36 weeks' gestation), admitted from 2004 to 2012.

RESULTS

Among 49 neonates 11 (22%) had postneonatal epilepsy, of which 9 (18%) were non-cooled and 2 (4%) were cooled (P=0.05). Six of 11 infants (55%) had West syndrome, 4 (36%) had focal epilepsy and 1 (9%) had Lennox-Gastaut Syndrome. At multiple logistic regression analysis MRI pattern significantly correlated with postneonatal epilepsy (OR 0.19, 95% CI 0.04-0.88, P=0.03). Extensive lesions in basal ganglia and thalami plus cortical and white matter were associated with postneonatal epilepsy.

CONCLUSIONS

Only perinatal asphyxia with extensive lesions in basal ganglia and thalami plus cortical and white matter lesion conveys a high risk for early and severe postneonatal epilepsy. Moreover, therapeutic hypothermia is associated with a decrease of the risk of developing postneonatal epilepsy.

Outcomes after acute symptomatic seizures in neonates

Acute symptomatic seizures are a common sign of neurological dysfunction and brain injury in neonates and occur in approximately one to three per 1000 live births. Seizures in neonates are usually a sign of underlying brain injury and, as such, are commonly associated with adverse outcomes. Neurological morbidities in survivors often co-occur; epilepsy, cerebral palsy, and intellectual disability often occur together in the most severely affected children. Risk factors for adverse outcome include prematurity, low Apgar scores, low pH on the first day of life, seizure onset <24 or >72 h after birth, abnormal neonatal neurological examination, abnormal neonatal electroencephalographic background, status epilepticus, and presence and pattern of brain injury (particularly deep gray or brainstem injury). Despite this list of potential indicators, accurate prediction of outcome in a given child remains challenging. There is great need for long-term, multicenter studies to examine risk factors for, and pathogenesis of, adverse outcomes following acute symptomatic seizures in neonates.

Mild hypothermia inhibits the Notch 3 and Notch 4 activation and seizure after stroke in the rat model

Ischemic brain injury is an important cause for seizure. Mild hypothermia of the brain or the whole body is an effective way to remit the post-stroke seizure. Our previous study revealed an implication of Notch 1 and 2 in the post-stroke seizure. This study further investigated the involvement of Notch 3 and 4 in post-stroke seizure and the effect of mild hypothermia on these two factors. A global cerebral ischemia (GCI) model was conducted in Sprague Dawley rats. Seizure activity was evaluated by the frequency of seizure attacks, seizure severity scores, and seizure discharges. Seizures were frequently occurred in the first and the second 24 h after GCI, however active whole-body cooling (mild hypothermia) and DAPT (Notch inhibitor) injection into the hippocampus, alone or in combination, alleviated seizure activity after GCI. Immunohistochemistry and Western blot assays revealed the up-regulation of Notch intracellular domain (NICD) 3 and 4 in the cerebral cortex and hippocampus following GCI, but mild hypothermia and DAPT inhibited the up-regulation of NICD 3 and 4. NF-κB, PPARα, PPARγ, cyclin D1, Sox2 and Pax6 are associated with the pathogenesis of diverse type of seizures. GCI induced NF-κB, cyclin D1, and Pax6 activity, but suppressed PPARγ. These effects of GCI were abolished by both mild hypothermia and DAPT treatment. This indicated the implication of Notch signaling in the effects of GCI. Collectively, mild hypothermia inhibits Notch 3 and Notch 4 activation and seizure after stroke in the rat model. This study adds to the further understanding of the pathogenesis of post-stroke seizures and the protective mechanism of mild hypothermia.

Detailed Magnetic Resonance Imaging (MRI) Analysis in Infantile Spasms

PURPOSE

To evaluate initial magnetic resonance imaging (MRI) abnormalities in infantile spasms, correlate them to clinical characteristics, and describe repeat imaging findings.

METHODS

A retrospective review of infantile spasm patients was conducted, classifying abnormal MRI into developmental, acquired, and nonspecific subgroups.

RESULTS

MRIs were abnormal in 52 of 71 infantile spasm patients (23 developmental, 23 acquired, and 6 nonspecific) with no correlation to the clinical infantile spasm characteristics. Both developmental and acquired subgroups exhibited cortical gray and/or white matter abnormalities. Additional abnormalities of deep gray structures, brain stem, callosum, and volume loss occurred in the structural acquired subgroup. Repeat MRI showed better definition of the extent of existing malformations.

CONCLUSION

In structural infantile spasms, developmental/acquired subgroups showed differences in pattern of MRI abnormalities but did not correlate with clinical characteristics.

Why West? Comparisons of clinical, genetic and molecular features of infants with and without spasms

Infantile spasms are the defining seizures of West syndrome, a severe form of early life epilepsy with poorly-understood pathophysiology. We present a novel comparative analysis of infants with spasms versus other seizure-types and identify clinical, etiological, and molecular-genetic factors preferentially predisposing to spasms. We compared ages, clinical etiologies, and associated-genes between spasms and non-spasms groups in a multicenter cohort of 509 infants (<12months) with newly-diagnosed epilepsy. Gene ontology and pathway enrichment analysis of clinical laboratory-confirmed pathogenic variant-harboring genes was performed. Pathways, functions, and cellular compartments between spasms and non-spasms groups were compared. Spasms onset age was similar in infants initially presenting with spasms (6.1 months) versus developing spasms as a later seizure type (6.9 months) but lower in the non-spasms group (4.7 months, p<0.0001). This pattern held across most etiological categories. Gestational age negatively correlated with spasms onset-age (r = -0.29, p<0.0001) but not with non-spasm seizure age. Spasms were significantly preferentially associated with broad developmental and regulatory pathways, whereas motor functions and pathways including cellular response to stimuli, cell motility and ion transport were preferentially enriched in non-spasms. Neuronal cell-body organelles preferentially associated with spasms, while, axonal, dendritic, and synaptic regions preferentially associated with other seizures. Spasms are a clinically and biologically distinct infantile seizure type. Comparative clinical-epidemiological analyses identify the middle of the first year as the time of peak expression regardless of etiology. The inverse association with gestational age suggests the preterm brain must reach a certain post-conceptional, not just chronological, neurodevelopmental stage before spasms manifest. Clear differences exist between the biological pathways leading to spasms versus other seizure types and suggest that spasms result from dysregulation of multiple developmental pathways and involve different cellular components than other seizure types. This deeper level of understanding may guide investigations into pathways most critical to target in future precision medicine efforts.

Synergistic effect of mild hypothermia and the Notch inhibitor DAPT against post stroke seizures

Seizure is a serious complication of stroke, indicating poor prognosis. Notch signaling is associated with neuronal activity. Inhibition of Notch signaling suppresses seizure activity induced by kainic acid. The present study investigated the effect of the Notch inhibitor, DAPT, alone or in combination with mild hypothermia, on post-stroke seizures. A global cerebral ischemia (GCI) model was performed in Sprague Dawley (SD) male rats. Seizure activity was evaluated by the frequency of seizure attacks, seizure severity scores, and seizure discharges. Without any intervention, seizures occurred intensively between 24h and 48h following GCI. Seizure activity was confirmed using EEG monitoring. The expression of Notch intracellular domains (NICD) 1 and 2 were up-regulated in the cerebral cortex and hippocampus following GCI. DAPT was injected into the hippocampus of the rats to inhibit local Notch signaling. Active whole-body cooling was performed to maintain the core temperatures of rats at 33.5°C (mild hypothermia). Mild hypothermia and DAPT synergistically inhibited NICD 1 and 2 up-regulation, and post-stroke seizures. GCI augmented excitatory synaptic neurotransmission by up-regulating glutamate receptor subunits (GluN2A, GluA1) and the cotransporter, NKCC1, but attenuated inhibitory synaptic neurotransmission by down-regulating gamma amino acid, butyric acid (GABA), and the cotransporter, KCC2. DAPT treatment normalized the homeostasis of excitatory and inhibitory synaptic neurotransmission, suggesting that aberrant activation of Notch signaling is involved in post-stroke seizures. The present study adds to the further understanding of the pathogenesis of post-stroke seizures and the improvement of the treatment provided with hypothermia.

Severe bilateral cerebellar edema from ingestion of ketamine: case report

The use of ketamine as a drug of abuse has increased and so too has the risk of accidental overdose. Here, the authors report the case of a 10-month-old infant who inadvertently ingested ketamine. The child demonstrated severe cerebellar swelling that required emergency surgical intervention. The authors describe the clinical course of this child and present the radiographic characteristics of the brain. The imaging characteristics were not consistent with purely anoxic injury, thus suggesting a specific effect of this drug. To the authors' knowledge, similar imaging characteristics in this context have not been described.

Prediction of Future Epilepsy in Neonates With Hypoxic-Ischemic Encephalopathy Who Received Selective Head Cooling

Epilepsy outcomes after therapeutic hypothermia for neonates with hypoxic-ischemic encephalopathy are understudied. The authors used multivariable logistic regression to predict epilepsy in neonates after selective head cooling. Sensitivity analyses used magnetic resonance imaging (MRI) and electroencephalogram (EEG) interpretations by different clinicians. Fifty neonates had 2-year follow-up. Nine developed epilepsy. Predictors included pH ≤6.8 on day of birth (adjusted odds ratio [OR] 19 [95% confidence interval (CI) 1-371]), burst suppression on EEG on day 4 (8.2 [1.3-59]), and MRI deep gray matter injury (OR 33 [2.4-460]). These factors stratify neonates into low (0-1 factors; 3% [0%-14%] risk), medium (2 factors; 56% [21%-86%] risk), and high-risk groups (3 factors; 100% [29%-100%] risk) for epilepsy. The stratification was robust to varying clinical interpretations of the MRI and EEG. Neonates with hypoxic-ischemic encephalopathy who undergo selective head cooling appear at risk of epilepsy if they have 2 to 3 identified factors. If validated, this rule may help counsel families and identify children for close clinical follow-up.

Therapeutic hypothermia for neonatal hypoxic ischemic encephalopathy is associated with short-term reduction of seizures after discharge from the neonatal intensive care unit

INTRODUCTION

Therapeutic hypothermia for the treatment of moderate to severe neonatal hypoxic ischemic encephalopathy has been shown to reduce death and disability, but the effects on seizures after discharge from the Neonatal ICU are not known.

METHODS

A retrospective cohort study was conducted involving 56 neonates admitted to the Neonatal ICU at Children's Hospital of Orange County, CA from January 1, 2007 to September 1, 2013 with hypoxic ischemic encephalopathy who met criteria for selective brain cooling. Fifteen patients received supportive care. Forty-one patients received cooling, of whom 25 were included for analysis. Sixteen patients from the hypothermia group and 12 from the no hypothermia group developed clinical seizures while inpatient. Up to 6 months, four patients (16%) had continued seizures in the therapeutic hypothermia group compared to eight (53%) patients who did not receive hypothermia.

DISCUSSION

Our study shows an association between therapeutic hypothermia and reduced seizures after discharge from the neonatal intensive care unit. The short duration of follow-up, 6 months, is a limitation of this study. Another limitation is its observational nature, where reasons for treatment selection and exclusions are unmeasurable confounding factors. Further studies are needed to determine long-term effects.

MRI Differences Associated with Intrauterine Growth Restriction in Preterm Infants

BACKGROUND

Preterm infants are at risk for neurodevelopmental impairment. Intrauterine growth restriction (IUGR) further increases this risk. Brain imaging studies are often utilized at or near term-equivalent age to determine later prognosis.

OBJECTIVE

To evaluate the association between intrauterine growth and regional brain volume on MRI scans performed in preterm infants at or near term-equivalent age.

METHODS

This is a retrospective case-control study of 24 infants born at gestational age ≤30 weeks and cared for in a large, inner-city, academic neonatal intensive-care unit from 2012 to 2013. Each IUGR infant was matched with 1-2 appropriate for gestational age (AGA) infants who served as controls. Predischarge MRI scans routinely obtained at ≥36 weeks' adjusted age were analyzed for regional brain volumetric differences. We examined the association between IUGR and thalamic, basal ganglion, and cerebellar brain volumes in these preterm infants.

RESULTS

Compared to AGA infants, IUGR infants had a smaller thalamus (7.88 vs. 5.87 mL, p = 0.001) and basal ganglion (8.87 vs. 6.92 mL, p = 0.002) volumes. There was no difference in cerebellar volumes between the two study groups. Linear regression analyses revealed similar trends in the associations between IUGR and brain volumes after adjusting for sex, gestational age at birth, and postconceptual age and weight at MRI.

CONCLUSIONS

Thalamus and basal ganglion volumes are reduced in growth-restricted preterm infants. These differences may preferentially impact neurodevelopmental outcomes. Further research is needed to explore these relationships.

Epilepsy Following Neonatal Seizures Symptomatic Of Stroke

Investigators from Child Neurology and Clinical Neurophysiology, Pediatric University Hospital, Padua, Italy studied the long term risk of developing epilepsy in patients with EEG confirmed neonatal seizures and arterial ischemic stroke.