Lauren C. Weeke

MRI and spectroscopy in (near) term neonates with perinatal asphyxia and therapeutic hypothermia

Background Previous studies have demonstrated the association of abnormalities on diffusion-weighted MRI (DW-MRI) and proton magnetic resonance spectroscopy (1H-MRS) in infants with perinatal asphyxia. The use of therapeutic hypothermia might change this association. Aim To study the association between DW-MRI and 1H-MRS and outcome after perinatal asphyxia and therapeutic hypothermia in infants with a gestational age of ≥36 weeks. Patients and methods Infants with perinatal asphyxia and therapeutic hypothermia (n=88) were included when an MR examination was performed within 7 days after birth. Apparent diffusion coefficient (ADC) values of the basal ganglia and thalamus were calculated, as were lactate/N-acetylaspartate (LAC/NAA) and N-acetylaspartate/choline (NAA/Cho) ratios. Death or an abnormal neurodevelopment at ≥24 months was considered an adverse outcome. Receiver operating characteristic analysis was performed to determine cut-off levels. Results Of the 88 infants, 22 died and 7 had an adverse neurodevelopmental outcome. In infants with an adverse outcome, ADC values of the basal ganglia and thalamus were significantly lower, and Lac/NAA ratios were significantly higher than in infants with a normal outcome. Areas under the curve of ADC of the basal ganglia, thalami and Lac/NAA ratio were 0.89, 0.88 and 0.87, respectively. NAA/Cho ratios were in this cohort not associated with outcome. Conclusions During and after therapeutic hypothermia, low ADC values and high Lac/NAA ratios of the basal ganglia and thalamus are associated with an adverse outcome in infants with perinatal asphyxia.

Lidocaine response rate in aEEG-confirmed neonatal seizures: Retrospective study of 413 full-term and preterm infants.

To investigate the seizure response rate to lidocaine in a large cohort of infants who received lidocaine as second‐ or third‐line antiepileptic drug (AED) for neonatal seizures.

The aetiology of neonatal seizures and the diagnostic contribution of neonatal cerebral magnetic resonance imaging

The aim of this study was to delineate aetiologies and explore the diagnostic value of cerebral magnetic resonance imaging (MRI) in addition to cranial ultrasonography (cUS) in infants presenting with neonatal seizures.

Lidocaine-Associated Cardiac Events in Newborns with Seizures : Incidence, Symptoms and Contributing Factors

Background: Lidocaine is an effective therapy for neonatal seizures; however, it is not widely used, presumably due to the risk of cardiac events. Objective: To investigate the incidence of cardiac events in full-term and preterm infants receiving lidocaine for seizures. Methods: Full-term (n = 368) and preterm (n = 153) infants, admitted to a level 3 neonatal intensive care unit from 1992 to 2012, who received lidocaine for seizures were retrospectively studied. The causal relation between reported cardiac events and lidocaine administration was evaluated based on expected plasma concentrations, symptoms and relevant interactions during cardiac events. Results: Cardiac events were reported in 11/521 infants (2.1%; 9 full-term, 2 preterm). In 7/11 infants the causal relation was considered plausible, in 3/11 questionable and in 1/11 implausible. The incidence was calculated to be 1.3-1.9% (n = 7-10/521), but was only 0.4% (n = 1/246, p = 0.02) when using reduced-dose regimens. Important risk factors for cardiac events were unstable potassium, (congenital) cardiac dysfunction and concurrent phenytoin use. Conclusions: Lidocaine-associated cardiac events were rare in our cohort, especially since the introduction of new reduced-dose regimens. This indicates that lidocaine is safe to use as an antiepileptic drug in full-term and preterm infants.

Carbon Dioxide Fluctuations Are Associated with Changes in Cerebral Oxygenation and Electrical Activity in Infants Born Preterm

OBJECTIVES To evaluate the effects of acute arterial carbon dioxide partial pressure changes on cerebral oxygenation and electrical activity in infants born preterm. STUDY DESIGN This retrospective observational study included ventilated infants born preterm with acute fluctuations of continuous end-tidal CO2 (etCO2) as a surrogate marker for arterial carbon dioxide partial pressure, during the first 72 hours of life. Regional cerebral oxygen saturation and fractional tissue oxygen extraction were monitored with near-infrared spectroscopy. Brain activity was monitored with 2-channel electroencephalography. Spontaneous activity transients (SATs) rate (SATs/minute) and interval between SATs (in seconds) were calculated. Ten-minute periods were selected for analysis: before, during, and after etCO2 fluctuations of ≥5  mm Hg. RESULTS Thirty-eight patients (mean ± SD gestational age of 29 ± 1.8 weeks) were included, with 60 episodes of etCO2 increase and 70 episodes of etCO2 decrease. During etCO2 increases, brain oxygenation increased (regional cerebral oxygen saturation increased, fractional tissue oxygen extraction decreased; P < .01) and electrical activity decreased (SATs/minute decreased, interval between SATs increased; P < .01). All measures recovered when etCO2 returned to baseline. During etCO2 decreases, brain oxygenation decreased (regional cerebral oxygen saturation decreased, fractional tissue oxygen extraction decreased; P < .01) and brain activity increased (SATs/minute increased, P < .05), also with recovery after return of etCO2 to baseline. CONCLUSION An acute increase in etCO2 is associated with increased cerebral oxygenation and decreased brain activity, whereas an acute decrease is associated with decreased cerebral oxygenation and slightly increased brain activity. Combining continuous CO2 monitoring with near-infrared spectroscopy may enable the detection of otherwise undetected fluctuations in arterial carbon dioxide partial pressure that may be harmful to the neonatal brain.

Punctate white matter lesions in full-term infants with neonatal seizures associated with SLC13A5 mutations

INTRODUCTION Early-onset epileptic encephalopathy caused by biallelic SLC13A5 mutations is characterized by seizure onset in the first days of life, refractory epilepsy and developmental delay. Little detailed information about the brain MRI features is available in these patients. METHODS Observational study describing the neuro-imaging findings in eight patients (five families) with mutations in the SLC13A5 gene. Seven infants had an MRI in the neonatal period, two had a follow-up MRI at the age of 6 and 18 months and one only at 13 months. One patient had follow-up MRIs at 11 and 16 months and 3 and 6 years of age, but no neonatal MRI. RESULTS All patients presented with refractory neonatal seizures on the first day of life after an uncomplicated pregnancy and term delivery. Six out of seven infants with a neonatal MRI had a characteristic MRI pattern, with punctate white matter lesions (PWML), which were no longer visible at the age of 6 months, but led to gliotic scarring visible on MRI at the age of 18 months. The same pattern of gliotic scarring was seen on the MRIs of the infant without a neonatal scan. One infant had signal abnormalities in the white matter suspected of PWML on T2WI, but these could not be confirmed on other sequences. CONCLUSION In infants presenting with therapy resistant seizures in the first days after birth, without a clear history of hypoxic-ischemic encephalopathy, but with PWML on their neonatal MRI, a diagnosis of SCL13A5 related epileptic encephalopathy should be considered.

A Comparison of the Thompson Encephalopathy Score and Amplitude-Integrated Electroencephalography in Infants with Perinatal Asphyxia and Therapeutic Hypothermia.

Background: In previous studies clinical signs or amplitude-integrated electroencephalography (aEEG)-based signs of encephalopathy were used to select infants with perinatal asphyxia for treatment with hypothermia. Aim: The objective of this study was to compare Thompson encephalopathy scores and aEEG, and relate both to outcome. Subjects and Methods: Thompson scores, aEEG, and outcome were compared in 122 infants with perinatal asphyxia and therapeutic hypothermia. Of these 122 infants, 41 died and 7 had an adverse neurodevelopmental outcome. A receiver operating characteristics (ROC) analysis was also performed. Results: Thompson scores were higher in infants with more abnormal aEEG background patterns (ANOVA, p < 0.001). The ROC analysis demonstrated that a Thompson score of 11 or higher or an aEEG background pattern of continuous low voltage or worse was associated with an adverse outcome (AUC 0.84 for both). Conclusions: High Thompson scores and a suppressed aEEG background pattern are associated with an adverse outcome after perinatal asphyxia and therapeutic hypothermia. Further studies are needed to identify the best technique with which to select patients for therapeutic hypothermia

Effect of general anesthesia on neonatal aEEG—A cohort study of patients with non-cardiac congenital anomalies

Introduction The aim of the current study was to determine the effect of general anesthesia on neonatal brain activity using amplitude-integrated EEG (aEEG). Methods A prospective cohort study of neonates (January 2013-December 2015), who underwent major neonatal surgery for non-cardiac congenital anomalies. Anesthesia was administered at the discretion of the anesthetist. aEEG monitoring was started six hours preoperatively until 24 hours after surgery. Analysis of classes of aEEG background patterns, ranging from continuous normal voltage to flat trace in six classes, and quantitative EEG-measures, using spontaneous activity transients (SATs) and interSATintervals (ISI), was performed. Results In total, 111 neonates were included (36 preterm/75 full-term), age at time of surgery was (median (range) 2 (0–32) days. During anesthesia depression of brain activity was seen, with background patterns ranging from flat trace to discontinuous normal voltage. In most patients brain activity was two background pattern classes lower during anesthesia. After cessation of anesthesia, recovery to preoperative brain activity occurred within 24 hours in 86% of the preterm and 96% of the term infants. Gestational age and the dose of sevoflurane were significantly associated with SAT-rate (F(2,68) = 9.288, p < 0.001) and ISI- durations during surgery (F(3,71) = 12.96, p < 0.001). Background pattern and quantitative EEG-values were not associated with brain lesions (χ2(4) = 2.086, ns). Conclusion aEEG shows a variable reduction of brain activity in response to anesthesia in neonates with noncardiac congenital anomalies, with fast recovery after cessation of anesthesia. This reduction is related to gestational age and the dose of sevoflurane. The aEEG offers the opportunity to monitor the depth of anesthesia in the neonate.

A Distinctive Ictal Amplitude-Integrated Electroencephalography Pattern in Newborns with Neonatal Epilepsy Associated with KCNQ2 Mutations

Background: Recurrent and prolonged seizures are harmful for the developing brain, emphasizing the importance of early seizure recognition and effective therapy. Amplitude-integrated electroencephalography (aEEG) has become a valuable tool to diagnose epileptic seizures, and, in parallel, genetic etiologies are increasingly being recognized, changing the paradigm of the workup and management of neonatal seizures. Objective: To report the ictal aEEG pattern in neonates with KCNQ2-related epilepsy. Subjects and Methods: In this multicenter descriptive study, clinical data and aEEG findings of 9 newborns with KCNQ2 mutations are reported. Results: Refractory seizures occurred in the early neonatal period with similar seizure type, including tonic features, apnea, and desaturation. A distinct aEEG seizure pattern, consisting of a sudden rise of the lower and upper margin of the aEEG, followed by a marked depression of the aEEG amplitude, was found in 8 of the 9 patients. Prompt recognition of this pattern led to early treatment with carbamazepine in the 2 most recent cases. Conclusion: Early recognition of the electroclinical phenotype by using aEEG may direct genetic testing and a precision medicine approach with sodium channel blockers in neonates with KCNQ2 mutations.

Severe hypercapnia causes reversible depression of aEEG background activity in neonates: an observational study.

Introduction Elevated carbon dioxide (CO2) blood levels have a depressant effect on the central nervous system and can lead to coma in adults. Less is known about the effect of CO2 on the neurological function of infants. Objective To describe the effect of acute severe hypercapnia (PaCO2 >70 mm Hg) on amplitude-integrated electroencephalography (aEEG) and cerebral oxygenation in newborn infants. Study design Observational study of full-term and preterm infants with acute severe hypercapnia (identified by arterial blood gas measurements), monitored with aEEG. Visual analysis of the aEEG was performed in all infants. In preterm infants <32 weeks postmenstrual age (PMA), analysis of two-channel EEG was performed. Mean spontaneous activity transients (SAT) rate (SATs/min), interval between SATs (ISI in seconds) and the ISI percentage (ISP) were calculated for 10-min periods before, during and after hypercapnia. Mean regional cerebral oxygen saturation (rScO2) and fractional tissue oxygen extraction (FTOE) measured with near-infrared spectroscopy were also calculated for these periods. Results Twenty-five infants (21 preterm, 4 full-term) comprising 32 episodes of acute severe hypercapnia were identified. Twenty-seven episodes were accompanied by a transient aEEG depression. Twenty-two episodes in 15 preterm infants <32 weeks PMA were quantitatively analysed. During hypercapnia, SAT rate decreased and ISI and ISP increased significantly. No significant change occurred in rScO2 or FTOE during hypercapnia. Conclusion Profound depression of brain activity due to severe hypercapnia is also seen in infants. It can be recognised by an acute depression of the aEEG, without clinically detectable changes in cerebral oxygenation.