Oral topiramate in neonates with hypoxic ischemic encephalopathy treated with hypothermia: a safety study

Emerging therapeutic strategies in hypoxic-ischemic encephalopathy: a focus on cognitive outcomes

Perinatal hypoxia-ischemia represents a significant risk to CNS development, leading to high mortality rates, diverse damages, and persistent neurological deficits. Despite advances in neonatal medicine in recent decades, the incidence of HIE remains substantial. Motor deficits can manifest early, while cognitive impairments may be diagnosed later, emphasizing the need for extended follow-up. This review aims to explore potential candidates for therapeutic interventions for hypoxic-ischemic encephalopathy (HIE), with a focus on cognitive deficits. We searched randomized clinical trials (RCT) that tested drug treatments for HIE and evaluated cognitive outcomes. The results included studies on erythropoietin, melatonin, magnesium sulfate, topiramate, and a combination of vitamin C and ibuprofen. Although there are several indications of the efficacy of these drugs among animal models, considering neuroprotective properties, the RCTs failed to provide complete effectiveness in the context of cognitive impairments derived from HIE. More robust RCTs are still needed to advance our knowledge and to establish standardized treatments for HIE.

Hypothermia combined with neuroprotective adjuvants shortens the duration of hospitalization in infants with hypoxic ischemic encephalopathy: Meta-analysis

Objective: Therapeutic hypothermia (TH) is the current standard of care for neonatal hypoxic-ischemic encephalopathy (HIE), yet morbidity and mortality remain significant. Adjuvant neuroprotective agents have been suggested to augment hypothermic-mediated neuroprotection. This analysis aims to identify the classes of drugs that have been used in combination with hypothermia in the treatment of neonatal HIE and determine whether combination therapy is more efficacious than TH alone. Methods: A systematic search of PubMed, Embase and Medline from conception through December 2022 was conducted. Randomized- and quasi-randomized controlled trials, observational studies and retrospective studies evaluating HIE infants treated with combination therapy versus TH alone were selected. Primary reviewers extracted information on mortality, neurodevelopmental impairment and length of hospitalization for meta-analyses. Effect sizes were pooled using a random-effects model and measured as odds ratio (OR) or mean difference (MD) where applicable, and 95% confidence intervals (CI) were calculated. Risk of bias was assessed using the tool from the Cochrane Handbook for Systematic Reviews of Interventions. Results: The search strategy collected 519 studies, 16 of which met analysis inclusion criteria. HIE infants totaled 1,288 infants from included studies, 646 infants received some form of combination therapy, while 642 received TH alone. GABA receptor agonists, NMDA receptor antagonists, neurogenic and angiogenic agents, stem cells, glucocorticoids and antioxidants were identified as candidate adjuvants to TH that have been evaluated in clinical settings compared to TH alone. Length of hospitalization was significantly reduced in infants treated with combination therapy (MD -4.81, 95% CI [-8.42. to -1.19], p = .009) compared to those treated with TH alone. Risk of mortality and neurodevelopmental impairment did not differ between combination therapy and TH alone groups. Conclusion: Compared to the current standard of care, administration of neuroprotective adjuvants with TH reduced the duration of hospitalization but did not impact the risk of mortality or neurodevelopmental impairment in HIE infants. Meta-analysis was limited by a moderate risk of bias among included studies and small sample sizes. This analysis highlights the need for preclinical trials to conduct drug development studies in hypothermic settings to identify relevant molecular targets that may offer additive or synergistic neuroprotection to TH, and the need for larger powered clinical trials to determine the dose and timing of administration at which maximal clinical benefits are observed for adjuvant neuroprotectants.

Neonatal Hypoxic-Ischemic Encephalopathy: Perspectives of Neuroprotective and Neuroregenerative Treatments

Hypoxic-ischemic encephalopathy (HIE) is a serious condition that could have deleterious neurological outcomes, such as cerebral palsy, neuromotor disability, developmental disability, epilepsy, and sensitive or cognitive problems, and increase the risk of death in severe cases. Once HIE occurs, molecular cascades are triggered favoring the oxidative stress, excitotoxicity, and inflammation damage that promote cell death via apoptosis or necrosis. Currently, the therapeutic hypothermia is the standard of care in HIE; however, it has a small window of action and only can be used in children of more than 36 gestational weeks; for this reason, it is very important to develop new therapies to prevent the progression of the hypoxic-ischemic injury or to develop neuroregenerative therapies in severe HIE cases. The objective of this revision is to describe the emerging treatments for HIE, either preventing cell death for oxidative stress, excitotoxicity, or exacerbated inflammation, as well as describing a new therapeutic approach for neuroregeneration, such as mesenchymal stem cells, brain-derived neurotrophic factor, and gonadotropin realizing hormone agonists.

Neonatal seizures treatment based on conventional multichannel EEG monitoring: an overview of therapeutic options

INTRODUCTION

Seizures are the main neurological emergency during the neonatal period and are mostly acute and focal. The prognosis mainly depends on the underlying etiology. Conventional multichannel video-electroencephalographic (cEEG) monitoring is the gold standard for diagnosis, but treatment remains a challenge.

AREAS COVERED

: This review, based on PubMed search over the last 4 decades, focuses on the current treatment options for neonatal seizures based on cEEG monitoring. There is still no consensus on seizure therapy, owing to poor scientific evidence. Traditionally, the first-line treatments are phenobarbital and phenytoin, followed by midazolam and lidocaine, but their efficacy is limited. Therefore, current evidence strongly suggests the use of alternative antiseizure medications. Randomized controlled trials of new drugs are ongoing.

EXPERT OPINION

: Therapy for neonatal seizures should be prompt and tailored, based on semeiology, mirror of the underlying cause, and cEEG features. Further research should focus on antiseizure medications that directly act on the etiopathogenetic mechanism responsible for seizures and are therefore more effective in seizure control.

Topiramate Is Safe for Refractory Neonatal Seizures: A Multicenter Retrospective Cohort Study of Necrotizing Enterocolitis Risk

BACKGROUND

A previously published, single-institution, case series suggested an association between topiramate administration in neonates and subsequent development of necrotizing enterocolitis (NEC). This contradicted our more extensive experiences using topiramate in this population. We therefore studied safety and tolerability of topiramate for treating refractory neonatal seizures, hypothesizing that the risk of developing NEC following topiramate exposure was low and that most infants tolerate topiramate.

METHODS

This multicenter retrospective cohort study included seventy-five neonates who received topiramate to treat seizures from January 2011 to October 2019 at three geographically diverse level IV neonatal intensive care units affiliated with pediatric tertiary hospitals. Data included demographics, birth history, seizure etiology, treatment response, side effects, and occurrence and details of NEC.

RESULTS

Three of seventy-five infants (4%) developed NEC following topiramate exposure. These infants did not differ in gestational age, birth weight, seizure etiology, postmenstrual age, weight when topiramate was initiated, or dosing of topiramate. Topiramate was well tolerated. Only three infants (4%) discontinued due to side effects. The most common side effect (20%) was weight loss (typically <5%). Topiramate was felt to be efficacious (61%). Most infants (72%) continued topiramate when discharged.

CONCLUSIONS

Our multicenter, 75-infant study demonstrated that development of NEC after treatment with topiramate was rare (4%) and refutes prior literature suggesting an association. Topiramate was felt to be efficacious and was well tolerated. Although limited by retrospective design, study data are broadly applicable and support thoughtful use of topiramate as a safe, reasonable option for treating refractory neonatal seizures.

Thiamine as a Possible Neuroprotective Strategy in Neonatal Hypoxic-Ischemic Encephalopathy

On the basis that similar biochemical and histological sequences of events occur in the brain during thiamine deficiency and hypoxia/ischemia related brain damage, we have planned this review to discuss the possible therapeutic role of thiamine and its derivatives in the management of neonatal hypoxic-ischemic encephalopathy (HIE). Among the many benefits, thiamine per se as antioxidant, given intravenously (IV) at high doses, defined as dosage greater than 100 mg IV daily, should counteract the damaging effects of reactive oxygen and nitrogen species in the brain, including the reaction of peroxynitrite with the tyrosine residues of the major enzymes involved in intracellular glucose metabolism, which plays a key pathophysiological role in HIE in neonates. Accordingly, it is conceivable that, in neonatal HIE, the blockade of intracellular progressive oxidative stress and the rescue of mitochondrial function mediated by thiamine and its derivatives can lead to a definite neuroprotective effect. Because therapeutic hypothermia and thiamine may both act on the latent period of HIE damage, a synergistic effect of these therapeutic strategies is likely. Thiamine treatment may be especially important in mild HIE and in areas of the world where there is limited access to expensive hypothermia equipment.

Current Therapies for Neonatal Hypoxic-Ischaemic and Infection-Sensitised Hypoxic-Ischaemic Brain Damage

Neonatal hypoxic-ischaemic brain damage is a leading cause of child mortality and morbidity, including cerebral palsy, epilepsy, and cognitive disabilities. The majority of neonatal hypoxic-ischaemic cases arise as a result of impaired cerebral perfusion to the foetus attributed to uterine, placental, or umbilical cord compromise prior to or during delivery. Bacterial infection is a factor contributing to the damage and is recorded in more than half of preterm births. Exposure to infection exacerbates neuronal hypoxic-ischaemic damage thus leading to a phenomenon called infection-sensitised hypoxic-ischaemic brain injury. Models of neonatal hypoxia-ischaemia (HI) have been developed in different animals. Both human and animal studies show that the developmental stage and the severity of the HI insult affect the selective regional vulnerability of the brain to damage, as well as the subsequent clinical manifestations. Therapeutic hypothermia (TH) is the only clinically approved treatment for neonatal HI. However, the number of HI infants needed to treat with TH for one to be saved from death or disability at age of 18-22 months, is approximately 6-7, which highlights the need for additional or alternative treatments to replace TH or increase its efficiency. In this review we discuss the mechanisms of HI injury to the immature brain and the new experimental treatments studied for neonatal HI and infection-sensitised neonatal HI.

Cooling and immunomodulation for treating hypoxic-ischemic brain injury

Therapeutic hypothermia is now well established to partially reduce disability in term and near-term infants with moderate-severe hypoxic-ischemic encephalopathy. Preclinical and clinical studies have confirmed that current protocols for therapeutic hypothermia are near optimal. The challenge is now to identify complementary therapies that can further improve outcomes, in combination with therapeutic hypothermia. Overall, anti-excitatory and anti-apoptotic agents have shown variable or even no benefit in combination with hypothermia, suggesting overlapping mechanisms of neuroprotection. Inflammation appears to play a critical role in the pathogenesis of injury in the neonatal brain, and thus, there is potential for drugs with immunomodulatory properties that target inflammation to be used as a therapy in neonates. In this review, we examine the evidence for neuroprotection with immunomodulation after hypoxia-ischemia. For example, stem cell therapy can reduce inflammation, increase cell survival, and promote cell maturation and repair. There are also encouraging preclinical data from small animals suggesting that stem cell therapy can augment hypothermic neuroprotection. However, there is conflicting evidence, and rigorous testing in translational animal models is now needed.

Topiramate for hypoxic ischemic encephalopathy: A systematic review protocol

BACKGROUND

Hypoxic ischemic encephalopathy (HIE) is brain injury caused by different reasons and the most common diagnosed is neonatal HIE. Most of the existing treatments have their own shortcomings or there are still some unexplained mechanisms in it. Topiramate (TPM) is a new drug for the treatment for seizures in neonates with HIE, but is currently used off-label. Our protocol aims to access the efficiency and safety of TPM for HIE.

METHODS AND ANALYSIS

Eight databases will be searched by 2 independent researchers for the article on the topic of using TPM as treatment for HIE, including PubMed, the Cochrane Central Register of Controlled Trials (Cochrane Library), Embase, and Web of Science, China National Knowledge Infrastructure (CNKI), Chinese Biomedical Literature Database (CBM), Wang Fang Database and Chinese Science and Technology Periodical database (VIP). The included papers are those published from the established date of the databases to 2019. The therapeutic effects based on the grade of neonatal behavioral neurological assessment will be regarded as the primary outcomes. RevMan V5.3 will be used to compute the data synthesis and carry out meta-analysis. The risk of bias will be appraised by the Cochrane risk of bias tool. Rare ratio for dichotomous outcomes and mean different for continuous data will be expressed with 95% confidence intervals (CI) for analysis. A random effects model or a fixed effects model will be employed, when heterogeneity is found or not. Subgroup analysis and sensitivity analysis will be applied if the heterogeneity is obvious.

RESULTS

This study will provide the recent evidence of TPM for HIE from reducing seizure acticity.

CONCLUSION

The conclusion of this study will provide proof to evaluate if TPM is effective and safe in the treatment of HIE.PROSPERO registration number: PROSPERO CRD42018117981.

Topiramate pharmacokinetics in neonates undergoing therapeutic hypothermia and proposal of an optimised dosing schedule

AIM

The adequate dosing of topiramate in neonates undergoing therapeutic hypothermia has not been established. The aim of this study was to design a dosing schedule capable of providing topiramate serum concentrations within the accepted therapeutic range.

METHODS

Neonates (n = 52) with hypoxic ischaemic encephalopathy and subjected to therapeutic hypothermia were dosed with topiramate, 5 mg/kg on day one and 3 mg/kg on days two to five, to decrease seizure events. A total of 451 topiramate serum concentrations obtained in the patients were used to develop a population pharmacokinetic model using a non-linear mixed-effects modelling approach.

RESULTS

A one-compartment model with first-order absorption and two different clearance terms, one for the cooling period and another for the post-warming period, were used to describe the concentration-time topiramate data. The probability of no-seizure events could not be related to topiramate concentrations, which was attributed to excessively low topiramate concentrations. A modified dosage schedule was designed with the aim of obtaining more than 90% of patients with topiramate concentrations within the therapeutic range after the first dose.

CONCLUSION

The dosage schedule of topiramate in these patients should be modified with the aim of decreasing the frequency of seizure events.

Update on the current management of newborns with neonatal encephalopathy

Hypoxic-ischemic encephalopathy is a subtype of neonatal encephalopathy and a major contributor to global neonatal morbidity and mortality. Despite advances in obstetric and neonatal care there are still challenges in accurate determination of etiology of neonatal encephalopathy. Thus, identification of intrapartum risk factors and comprehensive evaluation of the neonate is important to determine the etiology and severity of neonatal encephalopathy. In developed countries, therapeutic hypothermia as a standard of care therapy for neonates with hypoxic-ischemic encephalopathy has proven to decrease incidence of death and neurodevelopmental disabilities, including cerebral palsy in surviving children. Advances in neuroimaging, brain monitoring modalities, and biomarkers of brain injury have improved the ability to diagnose, monitor, and treat newborns with encephalopathy. However, challenges remain in early identification of neonates at risk for hypoxic-ischemic brain injury, and determination of the timing and extent of brain injury. Using imaging studies such as Neonatal MRI and MR spectroscopy have proven to be most useful in predicting outcomes in infants with encephalopathy within the first week of life, although comprehensive neurodevelopmental assessments still remains the gold standard for determining long term outcomes. Future studies are needed to identify other newborns with encephalopathy that might benefit from therapeutic hypothermia and to determine the efficacy of other adjunctive neuroprotective strategies. This review focuses on newer evidence and advances in diagnoses and management of infants with neonatal encephalopathy, including novel therapies, as well as prognostication of outcomes to childhood.

Pharmacologic Prevention and Treatment of Neonatal Brain Injury

Neonatal brain injury (NBI) remains a major contributor to neonatal mortality and long-term neurodevelopmental morbidity. Although therapeutic hypothermia is the only proven treatment to minimize brain injury caused by neonatal encephalopathy in term neonates, it provides incomplete neuroprotection. There are no specific drugs yet proven to prevent NBI in preterm neonates. This review discusses the scientific and emerging clinical trial data for several neuroprotective drugs in development, examining potential efficacy and safety concerns. Drugs with the highest likelihood of success and closest to clinical application include erythropoietin for term and preterm neonates and antenatal magnesium for preterm neonates.

Topiramate plus Cooling for Hypoxic-Ischemic Encephalopathy: A Randomized, Controlled, Multicenter, Double-Blinded Trial

BACKGROUND AND OBJECTIVES

Therapeutic interventions to improve the efficacy of whole-body cooling for hypoxic-ischemic encephalopathy (HIE) are desirable. Topiramate has been effective in reducing brain damage in experimental studies. However, in the clinical setting information is limited to a small number of feasibility trials. We launched a randomized controlled double-blinded topiramate/placebo multicenter trial with the primary objective being to reduce the antiepileptic activity in cooled neonates with HIE and assess if brain damage would be reduced as a consequence.

STUDY DESIGN

Neonates were randomly assigned to topiramate or placebo at the initiation of hypothermia. Topiramate was administered via a nasogastric tube. Brain electric activity was continuously monitored. Topiramate pharmacokinetics, energy-related and Krebs' cycle intermediates, and lipid peroxidation biomarkers were determined using liquid chromatography-mass spectrometry and MRI for assessing brain damage.

RESULTS

Out of 180 eligible patients 110 were randomized, 57 (51.8%) to topiramate and 53 (48.2%) to placebo. No differences in the perinatal or postnatal variables were found. The topiramate group exhibited less seizure burden in the first 24 h of hypothermia (topiramate, n = 14 [25.9%] vs. placebo, n = 22 [42%]); needed less additional medication, and had lower mortality (topiramate, n = 5 [9.2%] vs. placebo, n = 10 [19.2%]); however, these results did not achieve statistical significance. Topiramate achieved a therapeutic range in 37.5 and 75.5% of the patients at 24 and 48 h, respectively. A significant association between serum topiramate levels and seizure activity (p < 0.016) was established. No differences for oxidative stress, energy-related metabolites, or MRI were found.

CONCLUSIONS

Topiramate reduced seizures in patients achieving therapeutic levels in the first hours after treatment initiation; however, they represented only a part of the study population. Our results warrant further studies with higher loading and maintenance dosing of topiramate.

Current and Emerging Therapies in the Management of Hypoxic Ischemic Encephalopathy in Neonates

Neonatal hypoxic ischemic encephalopathy (HIE) presents a significant clinical burden with its high mortality and morbidity rates globally. Therapeutic hypothermia (TH) is now standard of care for infants with moderate to severe HIE, but has not definitively changed outcomes in severe HIE. In this review, we discuss newer promising markers that may help the clinician identify severity of HIE. Therapies that are beneficial and agents that hold promise for neuroprotection are described, both for use either alone or as adjuncts to TH. These include endogenous pathway modifiers such as erythropoietin and analogues, melatonin, and remote ischemic post conditioning. Stem cells have therapeutic potential in this condition, as in many other neonatal conditions. Of the agents listed, only erythropoietin and analogues are currently being evaluated in large randomized controlled trials (RCTs). Exogenous therapies such as argon and xenon, allopurinol, monosialogangliosides, and magnesium sulfate continue to be investigated. The recognition of tertiary mechanisms of brain damage has opened up new research into therapies not only to attenuate brain damage but also to promote cell repair and regeneration in a developmentally disorganized brain long after the perinatal insult. These alternative modalities may be especially important in mild HIE and in areas of the world where there is limited access to expensive hypothermia equipment and services.

Topiramate for Seizures in Preterm Infants and the Development of Necrotizing Enterocolitis

Neonatal seizures represent a significant health burden on the term and preterm neonatal population and are linked to poor long-term neurodevelopmental outcomes. Currently, there are no US Food and Drug Administration-approved antiepileptic drugs for neonates, and authors of the medical literature have yet to reach a consensus on the most adequate approach to neonatal seizures. Topiramate is readily used in the adult and older pediatric population for the management of migraines and partial-onset seizures. Topiramate continues to gain favor among pediatric neurologists who often recommend this medication as a third-line treatment of neonatal seizures. We report our recent experience with 4 preterm neonates, born between 2015 and 2017, who developed radiographic signs of necrotizing enterocolitis after receiving topiramate for seizures. Each was given oral topiramate for the treatment of electrographic and clinical seizures and developed the subsequent diagnosis of necrotizing enterocolitis, with abdominal distention, hemoccult-positive stools, and radiographic signs of intestinal distention and pneumatosis. More research regarding the risk factors of topiramate use in premature infants is needed.

Pharmacotherapy for Seizures in Neonates with Hypoxic Ischemic Encephalopathy

Seizures are common in neonates with moderate and severe hypoxic ischemic encephalopathy (HIE) and are associated with worse outcomes, independent of HIE severity. In contrast to adults and older children, no new drugs have been licensed for treatment of neonatal seizures over the last 50 years, because of a lack of controlled clinical trials. Hence, many antiseizure medications licensed in older children and adults are used off-label for neonatal seizure, which is associated with potential risks of adverse effects during a period when the brain is particularly vulnerable. Phenobarbital is worldwide the first-line drug and is considered standard of care, although there is a limited evidence base for its efficacy. Second-line agents include phenytoin, benzodiazepines, levetiracetam, and lidocaine. These drugs are discussed in more detail along with two emerging drugs (bumetanide and topiramate). More safety, pharmacokinetic, and efficacy data are needed from well-designed clinical trials to develop safe and effective antiseizure regimes for the treatment of neonatal seizures in HIE.

Safety and efficacy of topiramate in neonates with hypoxic ischemic encephalopathy treated with hypothermia (NeoNATI): a feasibility study

PURPOSE

To investigate the feasibility of a study based on treatment with topiramate (TPM) added to moderate hypothermia in newborns with hypoxic ischemic encephalopathy (HIE).

MATERIALS AND METHODS

Multicenter randomized controlled trial. Term newborns with precocious metabolic, clinical and electroencephalographic (EEG) signs of HIE were selected according to their amplified integrated EEG pattern and randomized to receive either TPM (10 mg/kg once a day for the first three days of life) plus moderate hypothermia or hypothermia alone. Safety was assessed by monitoring cardiorespiratory parameters and blood samples collected to check renal, liver, metabolic balance and TPM pharmacokinetics. Efficacy was evaluated by the combined frequency of mortality and severe neurological disability as primary outcome. Incidence of magnetic resonance injury, epilepsy, blindness, hearing loss, neurodevelopment at 18-24 months of life was assessed as secondary outcomes.

RESULTS

Forty-four asphyxiated newborns were enrolled in the study. Twenty one newborns (10 with moderate and 11 with severe HIE) were allocated to hypothermia plus TPM and 23 (12 moderate and 11 severe HIE) to hypothermia. No statistically or clinically significant differences were observed for safety, primary or secondary outcomes. However, a reduction in the prevalence of epilepsy was observed in newborns co-treated with TPM.

CONCLUSIONS

Results of this pilot trial suggest that administration of TPM in newborns with HIE is safe but does not reduce the combined frequency of mortality and severe neurological disability. The role of TPM co-treatment in preventing subsequent epilepsy deserves further studies.

Neonatal hypoxic ischemic encephalopathy: an update on disease pathogenesis and treatment

INTRODUCTION

Hypoxic ischemic encephalopathy (HIE) is the most important reason for morbidity and mortality in term-born infants. Understanding pathophysiology of the brain damage is essential for the early detection of patients with high risk for HIE and development of strategies for their treatments. Areas covered: This review discusses pathophysiology of the neonatal HIE and its treatment options, including hypothermia, melatonin, allopurinol, topiramate, erythropoietin, N-acetylcyctein, magnesium sulphate and xenon. Expert commentary: Several clinical studies have been performed in order to decrease the risk of brain injury due to difficulties in the early diagnosis and treatment, and to develop strategies for better long-term outcomes. Although currently standard treatment methods include therapeutic hypothermia for neonates with moderate to severe HIE, new supportive options are needed to enhance neuroprotective effects of the hypothermia, which should aim to reduce production of the free radicals and to have anti-inflammatory and anti-apoptotic actions.

Seizures and hypothermia: importance of electroencephalographic monitoring and considerations for treatment

Hypoxic-ischemic encephalopathy is a common cause of seizures in neonates. Despite the introduction of therapeutic hypothermia, seizure rates are similar to those reported in the pre-therapeutic hypothermia era. However, the seizure profile has been altered resulting in a lower overall seizure burden, shorter individual seizure durations, and seizures that are harder to detect. Electroencephalographic (EEG) monitoring is the gold standard for detecting all seizures in neonates and this is even more critical in neonates who are cooled, as they are often sedated, making seizures more difficult to detect. Several studies have shown that the majority of seizures in neonates undergoing therapeutic hypothermia remain subclinical, thus requiring EEG monitoring for diagnosis. Amplitude-integrated EEG monitoring is useful but shorter duration seizures are more likely to be missed. Evidence is emerging about the pharmacokinetic profile of routinely used antiepileptic drugs during therapeutic hypothermia and some modifications have been suggested, particularly for lidocaine use.

Hypoxic ischemic brain injury: Potential therapeutic interventions for the future

Perinatal hypoxic-ischemic brain injury is a common problem with potentially devastating impact on neurodevelopmental outcomes. While therapeutic hypothermia, the first available treatment for this disease, reduces the risk of death or major neurodevelopmental disability, the risk of major neurologic morbidity following HI remains significant. Basic research has identified cellular mechanisms that mediate neuronal death. This article reviews the cellular processes induced that lead to brain injury following HI, and identify treatments currently under investigation for potential translation to clinical trials.

Newly emerging therapies for neonatal seizures

The treatment of neonatal seizures has not changed significantly over the last 50 years despite advances in antiepileptic drug (AED) development for older children and adults. Recently new drugs have emerged some of which address age-specific challenges or mechanisms and will be discussed in this review. The loop diuretic bumetanide blocks the neuronal NKCC1 co-transporter and is thought specifically to supress seizures in the immature brain. Levetiracetam has been used in children and infants with good efficacy, an excellent safety profile, and near-ideal pharmacokinetic characteristics. Randomised controlled trials are now underway to test the efficacy of some newer AEDs for neonatal seizures. Topiramate has been shown to have neuroprotective properties in addition to its antiepileptic action and trials in babies with hypoxic-ischaemic encephalopathy are now planned. There is an urgent need to develop age-specific AEDs for preterm and term babies. These drugs must be evaluated with multicentre, collaborative trials using innovative methods and high ethical standards to overcome age-specific challenges with the ultimate aim of improving the outcome for neonates with seizures.

Heart Rate and Arterial Pressure Changes during Whole-Body Deep Hypothermia

Whole-body deep hypothermia (DH) could be a new therapeutic strategy for asphyxiated newborn. This retrospective study describes how DH modified the heart rate and arterial blood pressure if compared to mild hypothermia (MH). Fourteen in DH and 17 in MH were cooled within the first six hours of life and for the following 72 hours. Hypothermia criteria were gestational age ≥36 weeks; birth weight ≥1800 g; clinical signs of moderate/severe hypoxic-ischemic encephalopathy. Rewarming was obtained in the following 6-12 hours (0.5°C/h) after cooling. Heart rates were the same between the two groups; there was statistically significant difference at the beginning of hypothermia and during rewarming. Three babies in the DH group and 2 in the MH group showed HR < 80 bpm and QTc > 520 ms. Infant submitted to deep hypothermia had not bradycardia or Qtc elongation before cooling and after rewarming. Blood pressure was significantly lower in DH compared to MH during the cooling, and peculiar was the hypotension during rewarming in DH group. Conclusion. The deeper hypothermia is a safe and feasible, only if it is performed by a well-trained team. DH should only be associated with a clinical trial and prospective randomized trials to validate its use.

Plasma topiramate concentrations resulting from doses associated with neuroprotection against white matter injury and stroke in two strains of rat pups

BACKGROUND

Cerebral white matter (WM) injury and stroke are common neuropathological injuries in newborns with congenital heart defects (CHDs) requiring surgery. Previous investigations in Long Evans rat pups subjected to hypoxia-ischemia found that intraperitoneal (i.p.) topiramate (TPM) at 30 mg/kg, but not 50 mg/kg, conferred neuroprotection. In Sprague-Dawley pups, a dose of 30 mg/kg protected against stroke. Concentrations associated with neuroprotective doses were not measured. The aims of this investigation were to determine concentrations associated with neuroprotective doses and to investigate the pharmacokinetics (PK) of i.p. TPM.

METHODS

Concentration-time data following administration of 30 and 50 mg/kg doses were analyzed using nonlinear mixed-effect modeling.

RESULTS

Mean predicted steady-state maximum and average concentrations following 30 mg/kg TPM were 31.3 and 16.8 μg/ml in Long Evans and 39.9 and 24.4 μg/ml in Sprague-Dawley pups. Mean predicted steady-state maximum and average concentrations following 50 mg/kg TPM were 52.1 and 28.1 μg/ml in Long Evans and 66.5 and 40.6 μg/ml in Sprague-Dawley pups. The apparent clearance (CL/F) and apparent volume of distribution (V/F) were 0.0470 ml/min and 22.2 ml, respectively, for Long Evans and 0.0325 ml/min and 19.7 ml, respectively, for Sprague-Dawley pups.

CONCLUSION

TPM concentrations associated with neuroprotective doses were determined. Body size and strain were significant covariates on CL/F and V/F. Results provide targets for future neuroprotection studies.

Clinical management of seizures in newborns : diagnosis and treatment

Neonatal seizures can be classified as tonic, clonic, myoclonic, and subtle. A clinical diagnosis is not easy as seizures are usually subtle in neonates. In the majority of newborn infants seizures are subclinical. On the other hand, not all abnormal movements identified by clinicians as clinical seizures are accompanied by electroencephalographic seizure discharges in the EEG. Precise incidence is difficult to delineate and depends on study population and criteria used for diagnosis of seizures. Controversy exists as to whether neonatal seizures themselves cause damage to the developing brain, or if the damage is primarily due to the underlying cause of the seizures. As a result of this controversy there is ongoing discussion whether all seizures (both clinical and subclinical) should be treated. In addition, when (sub)clinical seizures are treated, there is no consensus about the most appropriate treatment for neonatal seizures and how to assess the efficacy of treatment. Current therapeutic options to treat neonatal seizures (i.e. primarily first-generation antiepileptic drugs [AEDs]) are relatively ineffective. In practice, phenobarbital still remains the drug of first choice for EEG confirmed or suspected seizures. Benzodiazepines are also used in (phenobarbital) refractory cases. Several (small) studies indicate that lidocaine is an effective drug for refractory seizures as second- or third-line treatment. Although data are scarce, some AEDs with a wide acceptance in adult and pediatric neurology practice are being used to treat neonatal seizures (i.e. second-generation AEDs). These drugs are chemically different from all first-generation AEDs and they have an effect on other pathways so they provide new pharmacological targets for controlling seizures in newborns. Levetiracetam, topiramate, felbamate, bumetanide, lamotrigine and vigabatrin are examples of these second-generation AEDs. There is an urgent need for prospective, randomized, controlled trials to assess the efficacy and safety of these second-generation AEDs in neonates. The aim of this review is to provide an overview of the current knowledge of diagnosis, the effect on brain injury, and the treatment of neonatal seizures.

Cooling for newborns with hypoxic ischaemic encephalopathy

BACKGROUND

Newborn animal studies and pilot studies in humans suggest that mild hypothermia following peripartum hypoxia-ischaemia in newborn infants may reduce neurological sequelae without adverse effects.

OBJECTIVES

To determine the effect of therapeutic hypothermia in encephalopathic asphyxiated newborn infants on mortality, long-term neurodevelopmental disability and clinically important side effects.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group as outlined in The Cochrane Library (Issue 2, 2007). Randomised controlled trials evaluating therapeutic hypothermia in term and late preterm newborns with hypoxic ischaemic encephalopathy were identified by searching the Oxford Database of Perinatal Trials, the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, 2007, Issue 2), MEDLINE (1966 to June 2007), previous reviews including cross-references, abstracts, conferences, symposia proceedings, expert informants and journal handsearching. We updated this search in May 2012.

SELECTION CRITERIA

We included randomised controlled trials comparing the use of therapeutic hypothermia with standard care in encephalopathic term or late preterm infants with evidence of peripartum asphyxia and without recognisable major congenital anomalies. The primary outcome measure was death or long-term major neurodevelopmental disability. Other outcomes included adverse effects of cooling and 'early' indicators of neurodevelopmental outcome.

DATA COLLECTION AND ANALYSIS

Four review authors independently selected, assessed the quality of and extracted data from the included studies. Study authors were contacted for further information. Meta-analyses were performed using risk ratios (RR) and risk differences (RD) for dichotomous data, and weighted mean difference for continuous data with 95% confidence intervals (CI).

MAIN RESULTS

We included 11 randomised controlled trials in this updated review, comprising 1505 term and late preterm infants with moderate/severe encephalopathy and evidence of intrapartum asphyxia. Therapeutic hypothermia resulted in a statistically significant and clinically important reduction in the combined outcome of mortality or major neurodevelopmental disability to 18 months of age (typical RR 0.75 (95% CI 0.68 to 0.83); typical RD -0.15, 95% CI -0.20 to -0.10); number needed to treat for an additional beneficial outcome (NNTB) 7 (95% CI 5 to 10) (8 studies, 1344 infants). Cooling also resulted in statistically significant reductions in mortality (typical RR 0.75 (95% CI 0.64 to 0.88), typical RD -0.09 (95% CI -0.13 to -0.04); NNTB 11 (95% CI 8 to 25) (11 studies, 1468 infants) and in neurodevelopmental disability in survivors (typical RR 0.77 (95% CI 0.63 to 0.94), typical RD -0.13 (95% CI -0.19 to -0.07); NNTB 8 (95% CI 5 to 14) (8 studies, 917 infants). Some adverse effects of hypothermia included an increase sinus bradycardia and a significant increase in thrombocytopenia.

AUTHORS' CONCLUSIONS

There is evidence from the 11 randomised controlled trials included in this systematic review (N = 1505 infants) that therapeutic hypothermia is beneficial in term and late preterm newborns with hypoxic ischaemic encephalopathy. Cooling reduces mortality without increasing major disability in survivors. The benefits of cooling on survival and neurodevelopment outweigh the short-term adverse effects. Hypothermia should be instituted in term and late preterm infants with moderate-to-severe hypoxic ischaemic encephalopathy if identified before six hours of age. Further trials to determine the appropriate techniques of cooling, including refinement of patient selection, duration of cooling and method of providing therapeutic hypothermia, will refine our understanding of this intervention.

Safety and efficacy of topiramate in neonates with hypoxic ischemic encephalopathy treated with hypothermia (NeoNATI)

BACKGROUND

Despite progresses in neonatal care, the mortality and the incidence of neuro-motor disability after perinatal asphyxia have failed to show substantial improvements. In countries with a high level of perinatal care, the incidence of asphyxia responsible for moderate or severe encephalopathy is still 2-3 per 1000 term newborns. Recent trials have demonstrated that moderate hypothermia, started within 6 hours after birth and protracted for 72 hours, can significantly improve survival and reduce neurologic impairment in neonates with hypoxic-ischemic encephalopathy. It is not currently known whether neuroprotective drugs can further improve the beneficial effects of hypothermia. Topiramate has been proven to reduce brain injury in animal models of neonatal hypoxic ischemic encephalopathy. However, the association of mild hypothermia and topiramate treatment has never been studied in human newborns. The objective of this research project is to evaluate, through a multicenter randomized controlled trial, whether the efficacy of moderate hypothermia can be increased by concomitant topiramate treatment.

METHODS/DESIGN

Term newborns (gestational age ≥ 36 weeks and birth weight ≥ 1800 g) with precocious metabolic, clinical and electroencephalographic (EEG) signs of hypoxic-ischemic encephalopathy will be randomized, according to their EEG pattern, to receive topiramate added to standard treatment with moderate hypothermia or standard treatment alone. Topiramate will be administered at 10 mg/kg once a day for the first 3 days of life. Topiramate concentrations will be measured on serial dried blood spots. 64 participants will be recruited in the study. To evaluate the safety of topiramate administration, cardiac and respiratory parameters will be continuously monitored. Blood samplings will be performed to check renal, liver and metabolic balance. To evaluate the efficacy of topiramate, the neurologic outcome of enrolled newborns will be evaluated by serial neurologic and neuroradiologic examinations. Visual function will be evaluated by means of behavioural standardized tests.

DISCUSSION

This pilot study will explore the possible therapeutic role of topiramate in combination with moderate hypothermia. Any favourable results of this research might open new perspectives about the reduction of cerebral damage in asphyxiated newborns.

Strategies for reducing the incidence of skin complications in newborns treated with whole-body hypothermia

OBJECTIVE

To present the results of a strategy designed to reduce the incidence of skin complications in newborns with hypoxic-ischemic encephalopathy treated with moderate whole-body hypothermia.

DESIGN

Retrospective study.

SETTING

Neonatal Intensive Care Unit (NICU).

PATIENTS

Thirty-nine neonates cooled in the considered period.

INTERVENTION

Starting from January 2008, for neonates treated with moderate whole-body hypothermia (33.5 °C), the cooling system was set in "automatic servo-controlled mode (ACM)", where the temperature of the circulating water could vary between 4 °C and 42 °C. Starting from January 2009, cooling blankets were used in another type of automatic mode, the "gradient variable mode (GVM)", where the circulating water was maintained at a specific pre-set gradient towards the patient's body temperature, and a specific nursing protocol (NP) was adopted.

MEASUREMENTS AND MAIN RESULTS

Two of the eleven newborns treated with the "ACM" exhibited skin complications compatible with subcutaneous fat necrosis (SFN). None of the twenty-eight newborns treated with the "GVM" exhibited skin complications. A comparison of the biochemical and hematological data between these two groups revealed that newborns treated after the adopting of a NP and the "GVM" showed lower serum protein C and calcium levels, and higher platelet levels.

CONCLUSIONS

Our data suggest that newborns undergoing therapeutic cooling may benefit from a specific NP and correct cooling unit setting. Should further studies confirm our data, this nursing approach could be easily adopted.

Hypothermia for neonatal hypoxic-ischemic encephalopathy: may an early amplitude-integrated EEG improve the selection of candidates for cooling?

OBJECTIVE

To report our experience in the selection of newborns candidate to therapeutic hypothermia.

METHODS

Retrospective study involving 47 newborns suffering from perinatal asphyxia from January 2008 to September 2011.

RESULTS

Thirty-five of 47 newborns admitted to our hospital fulfilled metabolic and neurological criteria for recruitment and were cooled. aEEG was carried out in 26 of them and resulted always abnormal. In three of the 12 newborns with only metabolic criteria, aEEG was moderately abnormal. They were cooled and their outcome (evaluated by General Movements and Griffiths Mental Development Scales for children aged 0-2 years) is good. Three additional newborns who only met the metabolic criterion reached our hospital after the therapeutic window for hypothermia and exhibited seizures; their outcome is poor.

CONCLUSIONS

In our experience, the inclusion of aEEG in the entry criteria would not have precluded newborns with neurological criteria from cooling. On the contrary, without an early aEEG, we would have excluded from hypothermia infants with moderate hypoxic-ischemic encephalopathy without precocious neurological signs who exhibited only the metabolic criterion, but with abnormal aEEG. If further studies will confirm that early aEEG might identify newborns suitable for cooling even in the absence of clinical signs, a revision of the entry criteria should be considered.

Hypoxic Ischemic Encephalopathy: Pathophysiology and Experimental Treatments

Hypoxic ischemic encephalopathy (HIE) is a serious birth complication affecting full term infants: 40-60% of affected infants die by 2 years of age or have severe disabilities. The majority of the underlying pathologic events of HIE are a result of impaired cerebral blood flow and oxygen delivery to the brain with resulting primary and secondary energy failure. In the past, treatment options were limited to supportive medical therapy. Currently, several experimental treatments are being explored in neonates and animal models to ameliorate the effects of secondary energy failure. This review discusses the underlying pathophysiologic effects of a hypoxic-ischemic event and experimental treatment modalities being explored to manage infants with HIE. Further research is needed to better understand if the long-term impact of the experimental treatments and whether the combinations of experimental treatments can improve outcomes in infants with HIE.

Pathophysiology of perinatal asphyxia: can we predict and improve individual outcomes?

Perinatal asphyxia occurs still with great incidence whenever delivery is prolonged, despite improvements in perinatal care. After asphyxia, infants can suffer from short- to long-term neurological sequelae, their severity depend upon the extent of the insult, the metabolic imbalance during the re-oxygenation period and the developmental state of the affected regions. Significant progresses in understanding of perinatal asphyxia pathophysiology have achieved. However, predictive diagnostics and personalised therapeutic interventions are still under initial development. Now the emphasis is on early non-invasive diagnosis approach, as well as, in identifying new therapeutic targets to improve individual outcomes. In this review we discuss (i) specific biomarkers for early prediction of perinatal asphyxia outcome; (ii) short and long term sequelae; (iii) neurocircuitries involved; (iv) molecular pathways; (v) neuroinflammation systems; (vi) endogenous brain rescue systems, including activation of sentinel proteins and neurogenesis; and (vii) therapeutic targets for preventing or mitigating the effects produced by asphyxia.

Treatment advances in neonatal neuroprotection and neurointensive care

Knowledge of the nature, prognosis, and ways to treat brain lesions in neonatal infants has increased remarkably. Neonatal hypoxic-ischaemic encephalopathy (HIE) in term infants, mirrors a progressive cascade of excito-oxidative events that unfold in the brain after an asphyxial insult. In the laboratory, this cascade can be blocked to protect brain tissue through the process of neuroprotection. However, proof of a clinical effect was lacking until the publication of three positive randomised controlled trials of moderate hypothermia for term infants with HIE. These results have greatly improved treatment prospects for babies with asphyxia and altered understanding of the theory of neuroprotection. The studies show that moderate hypothermia within 6 h of asphyxia improves survival without cerebral palsy or other disability by about 40% and reduces death or neurological disability by nearly 30%. The search is on to discover adjuvant treatments that can further enhance the effects of hypothermia.

Phenobarbital for neonatal seizures in hypoxic ischemic encephalopathy: a pharmacokinetic study during whole body hypothermia

PURPOSE

Therapeutic hypothermia has recently been introduced to treat term newborns with hypoxic-ischemic encephalopathy, of whom more than half have seizures. Phenobarbital is widely used to treat neonatal seizures, but it is unknown whether its pharmacokinetics is affected by hypothermia. We evaluated the influence of hypothermia on phenobarbital pharmacokinetics in asphyxiated newborns.

METHODS

Nineteen term asphyxiated newborns treated with mild whole body hypothermia, started within 6 h after birth and protracted for 72 h, received phenobarbital for clinical seizures. Treatment schedule consisted of a loading dose of 20 mg/kg, titrated to response, up to a maximum dose of 40 mg/kg, followed by a maintenance dose of 2.5 or 1.5 mg/kg every 12 h. Phenobarbital concentrations were measured on 28 dried blood spots in each newborn.

KEY FINDINGS

Eighteen newborns showed plasma concentrations within the reference range after receiving a loading dose of 20 mg/kg. In the remaining newborn, who had received a loading dose of 35 mg/kg, phenobarbital concentrations exceeded the upper reference limit. Phenobarbital concentrations reached a virtual steady state in all newborns. Pharmacokinetic parameters were then calculated. Minimum and maximum concentration (24.7 ± 8.8 and 30.63 ± 10.3 mg/L), average plasma concentration (27.37 ± 9.4 mg/L), and half-life (173.9 ± 62.5 h) were considerably higher than reported in literature for normothermic newborns. Pharmacokinetic parameters did not differ significantly between infants receiving different maintenance doses.

SIGNIFICANCE

Phenobarbital administered to newborns under whole body hypothermia results in higher plasma concentrations and longer half-lives than expected in normothermic newborns.

Cooling for newborns with hypoxic ischaemic encephalopathy

BACKGROUND

Newborn animal and human pilot studies suggest that mild hypothermia following peripartum hypoxia-ischaemia in newborn infants may reduce neurological sequelae, without adverse effects.

OBJECTIVES

To determine whether therapeutic hypothermia in encephalopathic asphyxiated newborn infants reduces mortality and long-term neurodevelopmental disability, without clinically important side effects.

SEARCH STRATEGY

The standard search strategy of the Neonatal Review Group as outlined in the Cochrane Library (Issue 2, 2003) was used. Randomised controlled trials evaluating therapeutic hypothermia in term newborns with hypoxic ischaemic encephalopathy were identified by searching the Oxford Database of Perinatal Trials, the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library Issue Issue 2, 2003), MEDLINE (1966 to July 2003), previous reviews including cross-references, abstracts, conferences, symposia proceedings, expert informants and journal hand searching.

SELECTION CRITERIA

Randomised controlled trials comparing the use of therapeutic hypothermia with normothermia in encephalopathic newborn infants with evidence of peripartum asphyxia and without recognisable major congenital anomalies were included. The primary outcome measure was death or long-term major neurodevelopmental disability. Other outcomes included adverse effects of cooling and 'early' indicators of neurodevelopmental outcome.

DATA COLLECTION AND ANALYSIS

Three reviewers independently selected, assessed the quality of and extracted data from the included studies. Authors were contacted for further information. Meta-analyses were performed using relative risk and risk difference for dichotomous data, and weighted mean difference for continuous data with 95% confidence intervals.

MAIN RESULTS

Two randomised controlled trials were included in this review, comprising 50 term infants with moderate/ severe encephalopathy and evidence of intrapartum asphyxia. There was no significant effect of therapeutic hypothermia on the combined outcome of death or major neurodevelopmental disability in survivors followed. No adverse effects of hypothermia on short term medical outcomes or on some 'early' indicators of neurodevelopmental outcome were detected.

REVIEWER'S CONCLUSIONS

Although two small randomised controlled trials demonstrated neither evidence of benefit or harm, current evidence is inadequate to assess either safety or efficacy of therapeutic hypothermia in newborn infants with hypoxic ischaemic encephalopathy. Therapeutic hypothermia for encephalopathic asphyxiated newborn infants should be further evaluated in well designed randomised controlled trials.