Neonatal convulsions: aetiology, late neonatal status and long-term outcome

Neonatal seizures in the U.S. National Inpatient Population: Prevalence and outcomes

BACKGROUND

Seizures are the most frequent neurological manifestation in neonates. Prevalence of neonatal seizures has not been well described in relationship with gestational age (GA). Also, the impact of seizures on neonatal mortality has not been quantified. This study aims to determine 1) prevalence of neonatal seizures in all GA groups, 2) associated mortality in each GA group and 3) impact of seizures on length of stay (LOS) of survivors in each GA group.

METHODS

Data from the national Kids' Inpatient Database (KID) for the years 2006, 2009 and 2012 was used in the study. All admitted infants with a documented GA were included in the study. All categorical variables were analyzed using Chi-square test, continuous variables were analyzed using t-test, and logistic regression analysis used to calculate odds ratio (OR) and 95% confidence intervals (CI).

RESULTS

A total of 10, 572,209 infants were included, of whom 4400 infants (0.04%) had seizures. The highest prevalence was at 24 weeks (0.12%). Overall mortality rate of patients with seizures was 4% with OR = 2.24 (95% CI = 1.90-2.65, p < 0.001). The correlation of seizure with mortality was significant after 33 weeks GA with greatest impact at 33-36 weeks GA (OR = 46.38 (95% CI = 26.86-80.08, p < 0.001). Seizures were associated with increased median LOS from 2 to 4 days (p < 0.001).

CONCLUSION

The prevalence of seizures varies according to gestational age ranging from 0.02% to 0.12%. The highest prevalence is at 24 weeks GA. The greatest impact for seizures on mortality is at 33-36 weeks GA.

Incidence of neonatal seizures, perinatal risk factors for epilepsy and mortality after neonatal seizures in the province of Parma, Italy

OBJECTIVE

Information about the incidence of neonatal seizures (NS) is scarce. Previous studies relied primarily on a clinical diagnosis of seizures. This population-based, retrospective study evaluated the incidence of electroencephalography (EEG)-confirmed seizures in neonates born in the province of Parma and the perinatal risk factors for mortality and epilepsy.

METHODS

All neonates with suspected seizures or with medical conditions at high risk for seizures from the study area were recorded in the neonatal intensive care unit (NICU) of the Parma University Hospital. NS were EEG confirmed. Perinatal risk factors for mortality and epilepsy after NS were evaluated with Cox's proportional hazards models.

RESULTS

In a 13-year period, 112 patients presented with NS: 102 newborns had electroclinical seizures (46 full-term and 56 preterm), whereas 10 presented only electrical seizures. The incidence was 2.29/1000 live births (95% confidence interval [CI] 1.87-2.72), with higher rates in preterm neonates (14.28/1000 in preterm vs 1.10/1000 in full-term infants). The incidence increased with decreasing gestational age (31-36 weeks of gestation: 5.01/1000, 28-30: 54.9/1000, and <28: 85.6/1000) and with decreasing birth weight (≥2500 g: 1.19/1000, <1000 g: 127.57/1000). Twenty-eight patients (25%) died, 16 (14.3%) had a diagnosis of epilepsy, 33 (29.5%) had cerebral palsy, and 39 (34.8%) had a developmental delay. Among the perinatal risk factors considered, the multivariate analysis showed an association between a 5-minute Apgar score of 0-7 and etiology with increased mortality and between female gender and status epilepticus with epilepsy.

SIGNIFICANCE

The incidence of NS is inversely associated with gestational age and birth weight. The etiology and a low Apgar score are strongly related to mortality; female gender and status epilepticus are risk factors for the development of epilepsy.

Continuous cardiotocography (CTG) as a form of electronic fetal monitoring (EFM) for fetal assessment during labour

BACKGROUND

Cardiotocography (CTG) records changes in the fetal heart rate and their temporal relationship to uterine contractions. The aim is to identify babies who may be short of oxygen (hypoxic) to guide additional assessments of fetal wellbeing, or determine if the baby needs to be delivered by caesarean section or instrumental vaginal birth. This is an update of a review previously published in 2013, 2006 and 2001.

OBJECTIVES

To evaluate the effectiveness and safety of continuous cardiotocography when used as a method to monitor fetal wellbeing during labour.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group Trials Register (30 November 2016) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials involving a comparison of continuous cardiotocography (with and without fetal blood sampling) with no fetal monitoring, intermittent auscultation intermittent cardiotocography.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility, quality and extracted data from included studies. Data were checked for accuracy.

MAIN RESULTS

We included 13 trials involving over 37,000 women. No new studies were included in this update.One trial (4044 women) compared continuous CTG with intermittent CTG, all other trials compared continuous CTG with intermittent auscultation. No data were found comparing no fetal monitoring with continuous CTG. Overall, methodological quality was mixed. All included studies were at high risk of performance bias, unclear or high risk of detection bias, and unclear risk of reporting bias. Only two trials were assessed at high methodological quality.Compared with intermittent auscultation, continuous cardiotocography showed no significant improvement in overall perinatal death rate (risk ratio (RR) 0.86, 95% confidence interval (CI) 0.59 to 1.23, N = 33,513, 11 trials, low quality evidence), but was associated with halving neonatal seizure rates (RR 0.50, 95% CI 0.31 to 0.80, N = 32,386, 9 trials, moderate quality evidence). There was no difference in cerebral palsy rates (RR 1.75, 95% CI 0.84 to 3.63, N = 13,252, 2 trials, low quality evidence). There was an increase in caesarean sections associated with continuous CTG (RR 1.63, 95% CI 1.29 to 2.07, N = 18,861, 11 trials, low quality evidence). Women were also more likely to have instrumental vaginal births (RR 1.15, 95% CI 1.01 to 1.33, N = 18,615, 10 trials, low quality evidence). There was no difference in the incidence of cord blood acidosis (RR 0.92, 95% CI 0.27 to 3.11, N = 2494, 2 trials, very low quality evidence) or use of any pharmacological analgesia (RR 0.98, 95% CI 0.88 to 1.09, N = 1677, 3 trials, low quality evidence).Compared with intermittent CTG, continuous CTG made no difference to caesarean section rates (RR 1.29, 95% CI 0.84 to 1.97, N = 4044, 1 trial) or instrumental births (RR 1.16, 95% CI 0.92 to 1.46, N = 4044, 1 trial). Less cord blood acidosis was observed in women who had intermittent CTG, however, this result could have been due to chance (RR 1.43, 95% CI 0.95 to 2.14, N = 4044, 1 trial).Data for low risk, high risk, preterm pregnancy and high-quality trials subgroups were consistent with overall results. Access to fetal blood sampling did not appear to influence differences in neonatal seizures or other outcomes.Evidence was assessed using GRADE. Most outcomes were graded as low quality evidence (rates of perinatal death, cerebral palsy, caesarean section, instrumental vaginal births, and any pharmacological analgesia), and downgraded for limitations in design, inconsistency and imprecision of results. The remaining outcomes were downgraded to moderate quality (neonatal seizures) and very low quality (cord blood acidosis) due to similar concerns over limitations in design, inconsistency and imprecision.

AUTHORS' CONCLUSIONS

CTG during labour is associated with reduced rates of neonatal seizures, but no clear differences in cerebral palsy, infant mortality or other standard measures of neonatal wellbeing. However, continuous CTG was associated with an increase in caesarean sections and instrumental vaginal births. The challenge is how best to convey these results to women to enable them to make an informed decision without compromising the normality of labour.The question remains as to whether future randomised trials should measure efficacy (the intrinsic value of continuous CTG in trying to prevent adverse neonatal outcomes under optimal clinical conditions) or effectiveness (the effect of this technique in routine clinical practice).Along with the need for further investigations into long-term effects of operative births for women and babies, much remains to be learned about the causation and possible links between antenatal or intrapartum events, neonatal seizures and long-term neurodevelopmental outcomes, whilst considering changes in clinical practice over the intervening years (one-to-one-support during labour, caesarean section rates). The large number of babies randomised to the trials in this review have now reached adulthood and could potentially provide a unique opportunity to clarify if a reduction in neonatal seizures is something inconsequential that should not greatly influence women's and clinicians' choices, or if seizure reduction leads to long-term benefits for babies. Defining meaningful neurological and behavioural outcomes that could be measured in large cohorts of young adults poses huge challenges. However, it is important to collect data from these women and babies while medical records still exist, where possible describe women's mobility and positions during labour and birth, and clarify if these might impact on outcomes. Research should also address the possible contribution of the supine position to adverse outcomes for babies, and assess whether the use of mobility and positions can further reduce the low incidence of neonatal seizures and improve psychological outcomes for women.

Epilepsy after neonatal seizures: literature review

INTRODUCTION

Acute neonatal seizures are the most frequent neurological complication in the neonatal intensive care units and the seizing newborns have an increased risk of long-term morbidity. However, the relationship between neonatal seizures and the development of epilepsy later in life is still unclear.

METHODS

We performed a literature review using the search terms "neonatal seizures AND outcome", "neonatal seizures AND epilepsy", "neonatal seizures AND post-neonatal epilepsy", including secondary sources of data such as reference lists of articles reviewed. From the studies in which data were available, the incidence of epilepsy was calculated by dividing the number of all subjects who developed epilepsy in the different studies considered with the number of all newborns enrolled to the studies less the number of patients lost at follow-up.

RESULTS

We found 44 studies published between 1954 and 2013, of which 4 were population-based studies and the remaining were hospital-based case series. The overall population evaluated was 4538 newborns and 17.9% developed post-neonatal epilepsy, with an onset within the first year of life in 68.5% of the patients. In 80.7%, epilepsy was associated with other neurological impairments.

CONCLUSION

Estimates on epilepsy after neonatal seizures vary widely depending on selection criteria and length of the follow-up. However, it represents a common outcome of these newborns, especially in those with severe brain injury and additional neurodevelopmental disabilities.

Continuous cardiotocography (CTG) as a form of electronic fetal monitoring (EFM) for fetal assessment during labour

BACKGROUND

Cardiotocography (known also as electronic fetal monitoring), records changes in the fetal heart rate and their temporal relationship to uterine contractions. The aim is to identify babies who may be short of oxygen (hypoxic), so additional assessments of fetal well-being may be used, or the baby delivered by caesarean section or instrumental vaginal birth.

OBJECTIVES

To evaluate the effectiveness of continuous cardiotocography during labour.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group Trials Register (31 December 2012) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials involving a comparison of continuous cardiotocography (with and without fetal blood sampling) with (a) no fetal monitoring, (b) intermittent auscultation (c) intermittent cardiotocography.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility, quality and extracted data from included studies.

MAIN RESULTS

Thirteen trials were included with over 37,000 women; only two were judged to be of high quality.Compared with intermittent auscultation, continuous cardiotocography showed no significant improvement in overall perinatal death rate (risk ratio (RR) 0.86, 95% confidence interval (CI) 0.59 to 1.23, n = 33,513, 11 trials), but was associated with a halving of neonatal seizures (RR 0.50, 95% CI 0.31 to 0.80, n = 32,386, nine trials). There was no significant difference in cerebral palsy rates (RR 1.75, 95% CI 0.84 to 3.63, n = 13,252, two trials). There was a significant increase in caesarean sections associated with continuous cardiotocography (RR 1.63, 95% CI 1.29 to 2.07, n = 18,861, 11 trials). Women were also more likely to have an instrumental vaginal birth (RR 1.15, 95% CI 1.01 to 1.33, n = 18,615, 10 trials).Data for subgroups of low-risk, high-risk, preterm pregnancies and high-quality trials were consistent with overall results. Access to fetal blood sampling did not appear to influence the difference in neonatal seizures nor any other prespecified outcome.

AUTHORS' CONCLUSIONS

Continuous cardiotocography during labour is associated with a reduction in neonatal seizures, but no significant differences in cerebral palsy, infant mortality or other standard measures of neonatal well-being. However, continuous cardiotocography was associated with an increase in caesarean sections and instrumental vaginal births. The challenge is how best to convey these results to women to enable them to make an informed choice without compromising the normality of labour.

Neurological outcome of newborns with neonatal seizures: a cohort study in a tertiary university hospital

OBJECTIVE: To describe the neurological outcome of newborns with seizures. METHOD: Cohort study with newborns prospectively followed. Perinatal characteristics and etiological screening were related to outcome in a regression model. RESULTS: During the study 3659 newborns were admitted and 2.7% were diagnosed as having seizures. Hypoxic ischemic encephalopathy (51%) was the etiology more frequently associated to seizures and also to postneonatal epilepsy (53%). In the follow up 25 died during the acute neonatal illness and 9 during the first years of life, 19 were diagnosed as having post neonatal epilepsy, 35 had developmental delay and 11 an association among this two comorbidities. A significant association between abnormal postnatal EEG and neuroimaging to developmental delay (p=0.014, p=0.026) was observed. The group of newborns that had seizures presented an increased risk of developing epilepsy compared to newborns from the same cohort without seizures (19.3/100 vs. 1.8/100, p<0.001). CONCLUSION: In this study neonatal seizures predominated in term newborns with perinatal asphyxia an elevated perinatal mortality and post neonatal morbidity was observed.The follow up showed an increased risk for developing postnatal epilepsy and developmental delay.

Preterm infants with video-EEG confirmed seizures: outcome at 30 months of age

OBJECTIVE

Our aim was to identify early predictors of poor neurodevelopmental outcome and of subsequent epilepsy in very early preterm and late preterm newborns with neonatal seizures.

STUDY DESIGN

Fifty-one preterm infants with gestational age (GA) <or=36 weeks were identified among those admitted to the NICU of University Hospital of Parma between January 1999 and December 2003 and prospectively followed-up. They were subdivided in two Groups: early preterm newborns with a GA <or=29 weeks and those with GA between 30 and 36 weeks. Selection criteria included multiple digital-video-EEG confirmed neonatal seizures and a follow-up of at least 30 months. Independent variables considered for analysis included neonatal risk factors, etiology and type of seizures, EEG activity, and cerebral ultrasound scan examinations.

RESULTS

Ten infants had a favorable outcome, 17 died, and 23 had an adverse outcome. One infant was lost on follow-up. Apgar score at 1 min (O.R.=15.457, 95% CI: 2.236-106.850, p=0.006) and severely abnormal background EEG activity (O.R.=8.298, 95% CI: 1.316-52.301, p=0.024) were independent predictors of abnormal outcome. Nine infants presented post-neonatal epilepsy. Severely abnormal Cerebral Ultrasound scans were predictive of epilepsy (O.R.=13.72, 95% CI: 1.959-96.149, p=0.008).

CONCLUSIONS

Neonatal seizures in preterm infants are associated to a high rate of mortality and severe morbidity in survivors but no definitive differences between the two groups of preterm infants were found. Risk-factors for development of subsequent epilepsy are strongly related to the underlying brain damage.

Neonatal Seizures: Gaps Between the Laboratory and the Clinic

Seizures in neonates (NBs) remain the most frequent neurological problem in the nursery. Considerable debate about their consequences exists between data and deductions reached through animal experimentations and those obtained through clinical investigations. The main conflicting issues are whether seizures in NBs can plant the roots for epileptogenesis and cause long-term deficits. The purpose of this chapter is to evaluate both laboratory and clinical results.

METHODS

Clinical data will be presented, including a 20-year-long cohort of NBs. This will be followed by the main seminal discoveries obtained in neonatal models. The phenomenon of transient or persistent dysmaturity following NB seizures will be discussed in relation to etiological factors.

RESULTS

The findings and deductions from animal models support the notions that epileptogenesis and cognitive deficits result from NB seizures. These conclusions contrast with clinical investigations maintaining that NB seizures, per se, are symptomatic markers of preexisting or of ongoing morbidities. The reasons for contrasting views will be discussed. Suggestions will be advanced for more animal models whose seizures are consistent with the etiologies and the phenotypes of human NB seizures.

Early-onset neonatal seizures: types, risk factors and short-term outcome

In a large majority of term newborns, early-onset neonatal seizures (EONS) are believed to relate to perinatal risk factors.

AIM

To identify risk factors for EONS.

METHODS

Among a cohort of 1293 newborns admitted over a period of 2 years to the neonatal intensive care unit of Tikur Anbasa Hospital, Addis Ababa, 93 had seizures. The case control study method was used to identify risk factors associated with EONS. Univariate analysis was used to further examine risk factors after adjusting for the effect of severe perinatal asphyxia (Apgar < or = 3).

RESULTS

A total of 78 (85%) term newborns had EONS. Hypoxic-ischaemic encephalopathy (OR 3.46, 95% CI 2.74-7.42) and shock (OR 2.53, 95% CI 1.51-4.76) were significantly associated with EONS. Multifocal clonic (66%) followed by focal clonic (22%) were the most common types of EONS. Nine (11%) of the newborns with EONS died. During follow-up, 37 (53%) of the 69 surviving newborns with EONS had psychomotor delay with or without neurological deficit.

CONCLUSION

Hypoxic-ischaemic encephalopathy and shock are important causes of EONS.

Continuous cardiotocography (CTG) as a form of electronic fetal monitoring (EFM) for fetal assessment during labour

BACKGROUND

Cardiotocography (sometimes known as electronic fetal monitoring), records changes in the fetal heart rate and their temporal relationship to uterine contractions. The aim is to identify babies who may be short of oxygen (hypoxic), so additional assessments of fetal well-being may be used, or the baby delivered by caesarean section or instrumental vaginal birth.

OBJECTIVES

To evaluate the effectiveness of continuous cardiotocography during labour.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group Trials Register (March 2006), CENTRAL (The Cochrane Library 2005, Issue 4), MEDLINE (1966 to December 2005), EMBASE (1974 to December 2005), Dissertation Abstracts (1980 to December 2005) and the National Research Register (December 2005).

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials involving a comparison of continuous cardiotocography (with and without fetal blood sampling) with (a) no fetal monitoring, (b) intermittent auscultation (c) intermittent cardiotocography.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed eligibility, quality and extracted data.

MAIN RESULTS

Twelve trials were included (over 37,000 women); only two were high quality. Compared to intermittent auscultation, continuous cardiotocography showed no significant difference in overall perinatal death rate (relative risk (RR) 0.85, 95% confidence interval (CI) 0.59 to 1.23, n = 33,513, 11 trials), but was associated with a halving of neonatal seizures (RR 0.50, 95% CI 0.31 to 0.80, n = 32,386, nine trials) although no significant difference was detected in cerebral palsy (RR 1.74, 95% CI 0.97 to 3.11, n = 13,252, two trials). There was a significant increase in caesarean sections associated with continuous cardiotocography (RR 1.66, 95% CI 1.30 to 2.13, n =18,761, 10 trials). Women were also more likely to have an instrumental vaginal birth (RR 1.16, 95% CI 1.01 to 1.32, n = 18,151, nine trials). Data for subgroups of low-risk, high-risk, preterm pregnancies and high quality trials were consistent with overall results. Access to fetal blood sampling did not appear to influence the difference in neonatal seizures nor any other prespecified outcome.

AUTHORS' CONCLUSIONS

Continuous cardiotocography during labour is associated with a reduction in neonatal seizures, but no significant differences in cerebral palsy, infant mortality or other standard measures of neonatal well-being. However, continuous cardiotocography was associated with an increase in caesarean sections and instrumental vaginal births. The real challenge is how best to convey this uncertainty to women to enable them to make an informed choice without compromising the normality of labour.

The current etiologic profile and neurodevelopmental outcome of seizures in term newborn infants

OBJECTIVES

The objectives of this study were to delineate the etiologic profile and neurodevelopmental outcome of neonatal seizures in the current era of neonatal intensive care and to identify predictors of neurodevelopmental outcome in survivors.

METHODS

Eighty-nine term infants with clinical neonatal seizures underwent neurologic examination, electroencephalography (EEG), neuroimaging, and extensive diagnostic tests in the newborn period. After discharge, all infants underwent regular neurologic evaluations and, at 12 to 18 months, formal neurodevelopmental testing. We tested the prognostic value of seizure etiology, neurologic examination, EEG, and neuroimaging.

RESULTS

Etiology was found in 77 infants. Global cerebral hypoxia-ischemia, focal cerebral hypoxia-ischemia, and intracranial hemorrhage were most common. Neonatal mortality was 7%; 28% of the survivors had poor long-term outcome. Association between seizure etiology and outcome was strong, with cerebral dysgenesis and global hypoxia-ischemia associated with poor outcome. Normal neonatal period/early infancy neurologic examination was associated with uniformly favorable outcome at 12 to 18 months; abnormal examination lacked specificity. Normal/mildly abnormal neonatal EEG had favorable outcome, particularly if neonatal neuroimaging was normal. Moderate/severely abnormal EEG, and multifocal/diffuse cortical or primarily deep gray matter lesions, had a worse outcome.

CONCLUSIONS

Mortality associated with neonatal seizures has declined although long-term neurodevelopmental morbidity remains unchanged. Seizure etiology and background EEG patterns remain powerful prognostic factors. Diagnostic advances have changed the etiologic distribution for neonatal seizures and improved accuracy of outcome prediction. Global cerebral hypoxia-ischemia, the most common etiology, is responsible for the large majority of infants with poor long-term outcome.

Risk factors for developing epilepsy after neonatal seizures

The objective of this study was to determine clinical and polysomnographic risk factors that might be early predictors for the development of postnatal epilepsy in a cohort of infants with seizures. The study sample included 158 infants who presented two or more clinically proven seizures. Gestational, perinatal, and polysomnographic data were obtained retrospectively. A questionnaire designed to detect patients with epilepsy in the community was prospectively given to all families, and the positive cases were reassessed for confirmation of epilepsy. Epilepsy rate after neonatal seizures was 22% within 12 months of follow-up and 33.8% within 48 months. Transient electrolytic imbalance and perinatal asphyxia were the most frequent etiologic factors associated with neonatal seizures. More than one seizure type was detected in 17.3% (n = 22) of cases and strongly associated with central nervous system infection (relative risk [RR] = 3.02, 95% confidence interval [CI] = 1.24-7.40, P = 0.02). Focal symptomatic epilepsy (P = 0.01) and syndromes not determined as focal or generalized (P = 0.04) were also associated with central nervous system infection. Abnormal polysomnographic recordings (P = 0.09) and abnormal neurologic examination on discharge (P < 0.01) were correlated with postnatal epilepsy. No differences were observed between premature and term infants concerning outcome. Neonatal seizures were associated with a high incidence of postnatal epilepsy in the cohort, including epileptic syndromes with catastrophic evolution. Abnormal neurologic examination on discharge was a good predictor of an unfavorable outcome and abnormal polysomnographic recording a moderate predictor.

Etiology of cerebral palsy

Cerebral palsy has a complex and multifactorial etiology. Approximately 5%-10% of cases can be ascribed to perinatal hypoxia, but the vast majority of cases are caused by the interplay of several risk factors and antenatal, perinatal, and neonatal events. The strongest risk factors include prematurity and low birth weight. The prevalence of cerebral palsy has remained constant despite improvements in obstetric and neonatal care. For a long time, the only causal factors explored to account for risk for cerebral palsy were complications of labor and delivery. As other periods have been investigated, new associations have come to light. The current understanding of contributors to the risk for cerebral palsy is still incomplete. Multiple causes may interact by way of excitotoxic, oxidative, or other converging pathophysiologic pathways. A single factor, unless present to an overwhelming degree, often may be insufficient to produce cerebral damage, whereas two or three interacting pathogenic assaults may overwhelm natural defenses and produce irreversible brain injury. The low prevalence of cerebral palsy makes the formal testing of preventative strategies difficult. There is a need for such strategies to be carefully assessed in well designed, multicenter, randomized, controlled trials before becoming part of clinical practice, however, so that the balance between harm and benefit is known in advance.

Demographic and intrapartum characteristics of term pregnancies with early-onset neonatal seizures

OBJECTIVE

To compare the demographic and intrapartum factors of term pregnancies in which early-onset neonatal seizures developed with the characteristics of a large, unselected control population.

STUDY DESIGN

Pregnancies delivered at term (gestational age > or = 37 weeks) in one birthing unit between 1984 and 1995 with a discharge diagnosis of neonatal seizures were identified. Maternal and neonatal charts of these patients were reviewed to confirm the diagnosis of early-onset seizure (EOS) which was defined as a clinical or EEG-diagnosed seizure within 72 hours of life. Demographic and intrapartum factors were compared between these EOS cases and all singleton term pregnancies delivered over the same time period in which there was no EOS. A regression model was then developed to determine factors predictive of EOS.

RESULTS

Of 80,561 total deliveries during the 11-year study period, there were 64,340 control and 62 EOS (0.1%) deliveries. Regression modeling identified NICU admission, depressed 1- and 5-minute Apgar scores, and neonatal intubation as predictors of EOS, but not operative vaginal, vaginal breech, or cesarean delivery.

CONCLUSION

Depressed condition at birth and/or the requirement for NICU care was the most important risk associated with early seizures in term infants.

The relationship between nucleated red blood cell counts and early-onset neonatal seizures

OBJECTIVE

This study was undertaken to better define the timing of neurologic insult in neonates with early-onset seizures through evaluation of neonatal nucleated red blood cell levels.

STUDY DESIGN

Medical records and the International Classification of Diseases, Ninth Revision codes were used to identify all term neonates with neonatal convulsions who were delivered at our institution (January 1, 1990-December 31, 1995). Each neonate with early-onset seizures was matched to the next 3 neonates who met the following criteria: gestational age > or =37 weeks, no early-onset seizures, birth weight > or =800 g, umbilical artery pH > or =7.25, and a 5-minute Apgar score >7. Demographic characteristics, clinical factors, and mean initial nucleated red blood cell counts were compared between groups.

RESULTS

During the 6-year study period, there were a total of 36, 490 singleton term deliveries of infants who were alive at birth. Forty-five (0.1%) of these neonates had early-onset seizures. Thirty neonates with early-onset seizures met the inclusion criteria. Mean nucleated red blood cell counts (number of nucleated red blood cells per 100 white blood cells) for neonates with early-onset seizures were significantly increased compared with those of control neonates (18.4 +/- 22.0 vs 4.6 +/- 4.5; P <.0008).

CONCLUSIONS

Our findings are suggestive of the hypothesis that neurologic injury leading to early-onset seizures often occurs before the intrapartum period.

Antepartum risk factors for newborn encephalopathy: the Western Australian case-control study

OBJECTIVE

To ascertain antepartum predictors of newborn encephalopathy in term infants.

DESIGN

Population based, unmatched case-control study.

SETTING

Metropolitan area of Western Australia, June 1993 to September 1995.

SUBJECTS

All 164 term infants with moderate or severe newborn encephalopathy; 400 randomly selected controls.

MAIN OUTCOME MEASURES

Adjusted odds ratio estimates.

RESULTS

The birth prevalence of moderate or severe newborn encephalopathy was 3.8/1000 term live births. The neonatal fatality was 9.1%. The risk of newborn encephalopathy increased with increasing maternal age and decreased with increasing parity. There was an increased risk associated with having a mother who was unemployed (odds ratio 3.60), an unskilled manual worker (3.84), or a housewife (2.48). Other risk factors from before conception were not having private health insurance (3.46), a family history of seizures (2.55), a family history of neurological disease (2.73), and infertility treatment (4.43). Risk factors during pregnancy were maternal thyroid disease (9.7), severe pre-eclampsia (6.30), moderate or severe bleeding (3.57), a clinically diagnosed viral illness (2.97), not having drunk alcohol (2.91); and placenta described at delivery as abnormal (2.07). Factors related to the baby were birth weight adjusted for gestational age between the third and ninth centile (4.37) or below the third centile (38.23). The risk relation with gestational age was J shaped with 38 and 39 weeks having the lowest risk.

CONCLUSIONS

The causes of newborn encephalopathy are heterogeneous and many of the causal pathways start before birth.

Does the onset of neonatal seizures correlate with the timing of fetal neurologic injury?

The onset of seizures after birth has been considered evidence of an intrapartum asphyxial event. The present study was undertaken to determine whether the timing of neonatal seizures after birth correlated with the timing of a fetal asphyxial event. Thus, singleton term infants diagnosed with hypoxic ischemic encephalopathy and permanent brain injury had a mean birth to seizure onset interval of 9.8 +/- 17.7 (range 1-90) hours. When these infants were categorized according to their fetal heart rate (FHR) patterns, the acute group (normal FHR followed by a sudden prolonged FHR deceleration that continued until delivery) tended to have earlier seizures than infants did within the tachycardia group (normal FHR followed by tachycardia, repetitive decelerations, and diminished variability) and the preadmission group (persistent nonreactive FHR pattern intrapartum). These seizure intervals were as follows: acute, 6.6 +/- 18.0 (range 1-90) hours; tachycardia, 11.1 +/- 17.1 (range 1-61) hours; and preadmission, 11.8 +/- 17.9 (range 1-79) hours (p < 0.05). But the range varied widely and no group was categorically distinct. In conclusion, the onset of neonatal seizures after birth does not, in and of itself, appear to be a reliable indicator of the timing of fetal neurologic injury.

Neurodevelopmental outcome of 'at risk' nursery graduates

A cohort study at a tertiary care neonatal service was undertaken to determine the neurodevelopmental outcome of neonates who required intensive care. One hundred and nineteen nursery graduates were enrolled for follow up if they fulfilled any of the following risk factors: birth weight less than 1500 g, Apgar score less than 4 at 5 minutes, seizure(s), and required assisted ventilation for more than 24 hours. They were subjected to periodic clinical evaluation and administered the Bayley Scales of Infant Development in early childhood. Of the total infants enrolled, 101 completed the required follow up. They included 55 infants with birth weight < 1500 g, 45 with low Apgar scores, 12 with seizure(s) and 28 who received assisted ventilation. An overwhelming majority of subjects (85%) had normal neurodevelopmental outcome. The adverse outcome in the remaining 15 included mental retardation in all, subnormal motor development in 14, microcephaly in 1, hearing loss in 2 and visual impairment in 4. Among the neonatal risk factors, seizures, sepsis and hypoxic ischemic encephalopathy had a significant association with adverse outcome. Despite serious neonatal morbidity, the early neurodevelopmental outcome of nursery graduates was reasonably good. The association of neonatal sepsis with neurodevelopmental sequelae merits a prospective evaluation.

Outcome of neonates with electrographically identified seizures, or at risk of seizures

A prospective study was conducted to investigate survival at 1 month and survival and developmental outcome at 1 year in a cohort of 53 neonates either suspected of or at risk of having seizures. For all patients, presence of seizures, diagnoses, and structural abnormalities were identified. If seizures were present, seizure variables were quantified. Correlations between neonatal parameters and subsequent outcome were investigated. Forty-three patients survived the first month of life. Background EEG was the only significant predictor of survival at 1 month. Three patients died after 1 month, and 2 of the three had extremely depressed interictal EEGs. Development outcome at 1 year was determined for all available surviving patients. Abnormal findings from brain imaging studies and number of independent electrographic seizure foci were correlated with some aspects of outcome at 1 year. No other correlations were identified between neonatal parameters and outcome.

Neonatal seizures: a clinician's overview

Seizures are the most frequent neurological event in newborns (NBs), provoked often by noxae not apt to cause them in later life. This is because receptor families of excitatory amino acids (EAA) are overexpressed at this stage of brain ontogenesis, which is also why most neonatal seizures rapidly abate, even when neurological deficits persist. The brain's immaturities dictate distinct seizure phenotypes. A classification proposed in the late 1960s has been criticized, and a new one has been advocated, based on correlations between EEGs and behaviors, leading to a classification of seizures into 'epileptic' and 'non-epileptic'. The taxonomic pitfalls of these classifications are discussed, and the notion advanced that many seizures fail to fulfil the criteria to label them as epileptic. While etiological factors have changed in time, the striking dichotomy in outcome has persisted. Many etiologies, often multifactorial, are unique in NBs, and they are discussed with reference to diagnosis and therapies. Four syndromes of NB seizures, accepted into the International Classification of the Epilepsies, are critically analyzed, some appearing to rest on fragile grounds. Controversies persist whether seizures per se are injurious to the immature brain. Clinical studies suggest that neither duration in days or length of seizure phenotypes correlates with outcomes, the most valid prognostic indices being offered by etiologies and by patterns of EEG polygraphy. However, because most seizures are symptomatic, it may be difficult to distinguish morbidity due to underlying pathology from that possibly added by seizures. Animal experiments suggested that they are injurious. The theory of energy failure, postulated to cause a cascade of events leading to inhibitions of DNA, proteins, lipids and disrupted neuronal proliferation, synaptogenesis, myelination, has largely been disproved. Brains of immature animals have been shown to have the oxidative machinery needed to fulfill energy demands, even during status convulsivus. They are also capable of using anaerobic metabolism and require less ATP when aerobic energy production ceases. Recent explanations for the injurious consequences of hypoxic ischemia and of prolonged convulsions postulate that neuronal damage occurs from excessive release of EAA which, by binding to their ligand-gated ionic receptors, cause a large influx of Ca2+, resulting in cell death. Because of the overabundance of EAA receptors in early ontogenesis, the excitotoxic hypothesis would appear attractive, but some observations militate against it. Among these is the dissociation found between the focal neurotoxicities induced by EAA injected into the brain and their absence following the concomitant convulsions. The latter are not blocked by pretreatment with EAA antagonists, while these prevent injuries caused by the injected EAA. There is no convincing evidence that excessive release of EAA occurs during NBs' seizures. Even if it does occur, it has been shown that immature neurons have a better capacity to self-protect from increased Ca2+ influx, and also that direct application of glutamate to immature neurons leads to significantly lower Ca2+ influx. These data raise doubts about the postulated excitotoxicity caused by NBs' seizures, being consistent with the fact that no one, so far, has observed neuronal damage from drug-induced convulsive states in NBs. Lack of overt neuronal injuries does not preclude that long-term subtle changes might be induced by noxae apt to provoke transient ictal events. Thus models developed in our laboratories demonstrate that long-term epileptogenicity results following postnatal O2 deprivation without evidence of neuronal injuries or of long-term behavioral or electrophysiological alteration. However, both age at which hypoxia occurs and specific proconvulsant methods used strictly determine whether increased epileptogenicity will occur.

Why has conventional intrapartum cardiotocography not given the expected results?

It is probable that conventional electronic fetal monitoring (EFM) has reduced the intrapartum death rate, but the expected dramatic reduction in neurological handicap has not occurred. There are two reasons for this: the majority of infants, who develop neurological problems have been harmed before the onset of labor, and the method of EFM has been more difficult to use in daily routine than expected. However, EFM is the best method we have to monitor high risk cases and the results can be improved by better training of the staff.

Neonatal seizures: long-term outcome and cognitive development among 'normal' survivors

The authors report the long-term outcome and cognitive development in the late-teenage years of 'normal' survivors of neonatal seizures. The outcome of the children was good, and normal in that they had attended normal schools and had normal overall intelligence test scores as adults. However, all of the sample displayed abnormal neuropsychological development in terms of intelligence test profile and subtest scatter, or development of spelling, or development of memory. This was independent of social and behavioural difficulties, which may also be increased. Neonatal seizures may be indicative of a subtle neurodevelopmental vulnerability which may manifest later in life as specific learning difficulties or poor social adjustment.

Evolution of neonatal seizures

The evolution of the diagnosis, etiology, management, and prognosis of neonatal seizures over the past two decades is reviewed. Seizures in the neonate are unique and require special classification. They result from acquired or congenital abnormalities of the central nervous system. Clustering of prognostic parameters, including seizure characteristics, perinatal factors, neurologic signs, cause, and neuroimaging and electroencephalographic abnormalities, allows neonatal seizures to be viewed as clinical syndromes with predictable outcomes.

Effects of postnatal electroshock convulsions on epileptogenesis of the amygdala and hippocampus in adult rats

Adult rats which received repeated electroshock convulsions (ESCs) during postnatal development underwent electrical kindling of the amygdala (AM) and hippocampus (HIPP). Completion of kindling, especially AM kindling, was significantly faster in the groups with ESCs from the neonatal to late infantile age than in the control group. It is discussed that especially the late infantile age in the postnatal development was supposed to play an important role in the faster kindling brought about by postnatal convulsions and that the faster kindling was due in part to abbreviation of the partial seizure process. However, the neonatal ESC group showed significantly delayed completion of HIPP kindling.

Postnatal epilepsy after EEG-confirmed neonatal seizures

We examined infants whose neonatal seizures were confirmed by randomly recorded ictal EEG tracings to determine the types and frequency of postnatal epilepsy (PNE)--unprovoked, recurring postnatal seizures. Perinatal and postnatal clinical and EEG variables were also examined for their relevance to PNE. Forty infants with EEG-documented neonatal seizures of diverse etiologies were studied. The 27 survivors were followed for a mean of 31 months. PNE developed in 56% (15 of 27) of the cohort. The first seizure appeared at a mean-corrected age of 12.7 months and occurred despite ongoing antiepileptic medication in 60% (9 of 15) of the group. Seizures were classified as infantile spasms or minor motor (7 patients), complex partial (4 patients), or generalized tonic-clonic (4 patients). Perinatal variables that significantly correlated with PNE included the presence of coma but not the age at seizure onset, the estimated gestational age, or Apgar scores. PNE occurred in 68% (13 of 19) of patients with moderately or markedly abnormal EEG backgrounds but in only 25% (2 of 8) without (p = 0.035). There was a strong trend for PNE to develop in patients with greater than 10 electrographic seizures per hour but in only 45% (9 of 20) of infants with fewer seizures (p = 0.058). Several postnatal variables were significantly related to PNE--the presence of cerebral palsy (CP), mental retardation (MR), CP with MR, and follow-up EEGs. PNE occurred in only 27% (3 of 11) of patients without spikes or sharp waves on postnatal EEGs performed at age 3 months but in 100% (3 of 3) of patients with spikes or sharp waves (p = 0.022).(ABSTRACT TRUNCATED AT 250 WORDS)

The risk of convulsions: a longitudinal study of normal babies and infants with neonatal damage in the first 6 years of life

After carefully reviewing the epidemiological literature on this subject, we assessed the risk of febrile, isolated or epileptic convulsions in normal babies and infants with neonatal damage. We considered 417 term or preterm infants with birth injury and compared them with 400 healthy full-term newborns, all born between 1978 and 1980, studying each one individually until at least the age of 6 using the chi 2 test, the risk factors in relation to the convulsive outcome in all the groups were processed. We also calculated the relative risk of outcome of both febrile convulsions and epilepsy. Our results show that as far as the onset of seizure disorders in the term infant is concerned, the predisposing factors are asphyxia, neurological syndrome, and previous barbiturate intake. In contrast with this, for premature infants the risk factors are severe apnea and severe prematurity.

Cerebral palsy among children born during the Dublin randomised trial of intrapartum monitoring

In a randomised trial involving 13,079 liveborn children intrapartum care by electronic fetal heart rate monitoring, with scalp blood sampling when indicated, was associated with a 55% reduction in neonatal seizures. Reassessment, when aged 4, of the 9 children in the intensively monitored group and 21 in the control group who survived after neonatal seizures showed that 3 such children in each group had cerebral palsy. A fourth child in the intensively monitored group with cerebral palsy had had transient abnormal neurological signs during the neonatal period. 8 other children in the intensively monitored group and 7 in the control group who had not had abnormal neurological signs in the neonatal period also had cerebral palsy. 16 (78%) of the total of 22 cases of cerebral palsy had not shown clinical signs suggestive of intrapartum asphyxia. Thus, compared with intermittent intrapartum monitoring, intensive monitoring has little, if any, protective effect against cerebral palsy.

Clinical spectrum and outcome of neonatal convulsions

The clinical spectrum and outcome of neonatal convulsions within an obstetric hospital population were reviewed for the 5 years, 1978-82, inclusive. There were 156 convulsing neonates managed at the Mater Mothers Hospital (110 inborn, 46 outborn). The incidence of early neonatal convulsions for inborn babies was 3.0/1000 live births. Antenatal and perinatal risk factors were compared between the 156 convulsing infants and the 36,082 infants born during the same period who did not convulse. The leading risk factors for convulsions were prematurity, intra-uterine growth retardation, low 5 min Apgar score, pre-eclampsia, antepartum haemorrhage, twin pregnancy and breech presentation. The predominant seizure type was tonic in 28.6%, multifocal clonic in 27.2%, subtle in 18.4%, myoclonic in 15.0% and focal clonic in 8.8%. Mortality (31%) and long-term disability (43%) rates were high. Tonic seizures had the highest mortality and morbidity. Throughout the duration of the study period infants received increasingly thorough investigation. Causative factors were determined in 95% of convulsing infants, most frequent being hypoxic-ischaemic encephalopathy (40.3%) and cerebroventricular haemorrhage (30.5%). Follow-up data on 99 of the 107 survivors (93%) revealed severe disability in 25, moderate disability in eight and mild disability in 10. A poor long-term prognosis was associated with prolonged convulsions, tonic and multifocal clonic convulsions, convulsions due to asphyxia and cerebroventricular haemorrhage and an abnormal neurological examination at discharge.

Is perinatal mortality still a good indicator of perinatal care?

The increasing influence of very immature infants on perinatal mortality rates (PMR) led us to question the usefulness of this parameter in assessing perinatal care. To examine this further we have compared the incidence of perinatal asphyxia amongst mature babies (greater than or equal to 35 weeks gestation) for two geographically-defined populations of over 500,000 people. Both areas have a teaching hospital-based maternity service and comparable perinatal mortality rates. The incidence of severe post-asphyxial encephalopathy showed a marked excess in one population (1.93 vs 0.61 per 1000 births), which was not obviously explicable. Taken in conjunction with the figures for stillbirth in labour, this represented a 2.8 times greater risk for either fetal death in labour or severe asphyxial insult. It would appear that perinatal mortality rates do not accurately reflect important differences in those perinatal outcomes most likely to be affected by perinatal care.

Antecedents and outcome of very early neonatal seizures in infants born at or after term

Recent experimentally derived evidence has confirmed earlier suggestions that seizures which occur within 48 h of birth in babies born at or later than 37 completed weeks gestation are particularly likely to reflect intrapartum asphyxia. We have compared 54 cases of such seizures with 41,090 controls in a geographically defined population. Nulliparity, hydramnios, post-term pregnancy, oxytocin augmentation of labour, abnormalities of fetal heart rate and/or meconium-stained amniotic fluid, prolonged second stage of labour, emergency caesarean section, assisted vaginal delivery, low Apgar score and resuscitation at delivery and subsequent ventilatory support were all statistically significantly more common among cases than among controls. Five of the 54 babies who developed seizures died within 28 days of birth and 11 of the 49 survivors had an impairment diagnosed by 3 years of age which was usually associated with some degree of cerebral palsy. Comparison of the frequency of antecedent perinatal risk factors in the seizure babies who died, those who survived with disabilities and normal survivors failed to reveal any clear pattern.

Cotside EEG monitoring using computerised spectral analysis

The application and interpretation of computerised spectral analysis of the neonatal electroencephalogram (EEG) using the Neuroscience Berg Fourier Analyser (BFA) is described. Recordings are immediately available at the cotside. Electrophysiological changes can be recognised by individuals with no previous experience in EEG technology. The compact nature of the analysis allows long periods of recording to be viewed within minutes. In addition to the unequivocal demonstration of both clinical and subclinical seizures, the BFA is useful in the evaluation of interseizure activity--that is, disturbance of sleep patterns, electrical output, and hemisphere asymmetry.

Cause of neonatal convulsions. Towards more precise diagnosis

All infants presenting with neonatal seizures over a two year period were carefully investigated for the cause. In 20% either intracranial haemorrhage or infarction of a major cerebral artery was detected by real time ultrasound. Routine imaging techniques should be performed in all infants with neonatal convulsions.

Obstetric characteristics and fetal heart rate patterns of infants who convulse during the newborn period

Seizure activity in the immediate neonatal period has been shown to correlate with long-term neurological handicap. The perinatal course of 34 term and 32 preterm infants who developed seizure activity in the neonatal period was compared to that of 66 matched control infants without neonatal seizure activity. The incidence of antenatal complications and abnormal fetal heart rate patterns and the percentages of abnormal labor, operative delivery, and low Apgar scores were significantly greater in the study infants than in the control infants. Earlier onset of seizure activity was seen in term versus preterm infants and term infants with abnormal versus normal fetal heart rate patterns. Management decisions regarding intervention or nonintervention based on fetal heart rate patterns were deemed appropriate in 31 of 34 term infants, yet short- and long-term neurological sequelae were significant.

Early seizures indicate quality of perinatal care

An analysis of antepartum, intrapartum, and postpartum variables was performed in a retrospective controlled study of 34 normally formed term infants who had perinatal asphyxia and subsequently displayed generalised seizures within 48 hours of birth. The aim was to identify any association, firstly between these variables and seizures, and secondly between these variables and subsequent morbidity and mortality among the seizure group. Maternal age greater than 35 years, duration of labour, meconium stained liquor, abnormal intrapartum fetal heart rate trace, and operative delivery were associated with seizures. A low Apgar score at five minutes, and intermittent positive pressure ventilation at birth of longer than 10 minutes were associated with subsequent morbidity and mortality. A striking relation between poor intrauterine growth and either death or handicap in the asphyxia group emphasised the value of growth measurements as a predictor of outcome. The overall incidence of seizures was 1.6 per 1000 term deliveries. There was a significant correlation between the seizure incidence and the intrapartum mortality rate. The incidence of seizures secondary to asphyxia in term infants, occurring less than 48 hours after delivery, may be a valuable index of the quality of perinatal care.

Periventricular infarction diagnosed by ultrasound: a postmortem correlation

Ultrasound brain scans sometimes demonstrate increased echogenicity or cysts, or both, in the periventricular white matter, superolateral to the ventricle, in the most common site of periventricular infarction. Over 33 months, 23 preterm infants dying after 20 or more days of life were entered into this study. Superolateral echogenicity or cysts were found in 13 (57%) cases. Periventricular infarction was present at autopsy in 12 (52%) cases. Ultrasound accurately diagnosed the size, site, and extent of periventricular infarction in 78% of scans. Interpretive errors were made with poor-quality scans and with early and late studies. We conclude that sector ultrasound brain scans accurately diagnose major periventricular infarction. Hemorrhage into the site of infarction is not a prerequisite for diagnosis of periventricular infarction by ultrasound.

Neonatal hypoxia and epileptic risk: a clinical prospective study

A historical cohort study was undertaken to determine the risk of epilepsy in a population of 371 newborns with an acute neurological disorder related to fetal and/or neonatal hypoxia compared with a control population of 362 normal newborns. The results showed that the risk of epilepsy was 5.1 times higher in the group of subjects affected at birth by a hypoxia-related acute neurological syndrome than in the control group. (Although the incidence of epilepsy is higher in the first year of life, epileptic seizures connected to perinatal hypoxia may occur in early childhood or later on.) Also, there were frequently persistent neuropsychiatric disorders in children with perinatal hypoxia (5.4%). There was no difference in the two groups regarding the incidence of febrile convulsions. The data show that perinatal hypoxia plays a role in the etiology of epilepsy, although at birth the hypoxia might result in only a modest and oftentimes completely reversible neurological syndrome.

Outcome in neonates with convulsions treated in an intensive care unit

Neurological and developmental outcome was assessed in 131 survivors of neonatal seizures aged 1 to 5 years who had been treated in a single intensive care unit from 1976 to 1979. Half the children had been born at less than 37 weeks' gestational age, and 28% at 31 weeks or less. Fifty-one children were normal on examination, 17 had minor abnormalities, 25 had moderate disabilities, 30 had severe disabilities, 6 had died because of profound neurological deficits, and 2 could not be located. Recurrent nonfebrile seizures had developed in 26 children. Most children with motor handicaps or visual loss were intellectually retarded, but 10 of 15 children with bilateral hearing loss were intellectually normal. Of 77 children whose seizures were caused by a hypoxic-ischemic insult, 41 developed moderate or severe disabilities. As determined by multivariate analysis, significant neonatal predictors of poor outcome in this group included seizures with late onset, tonic seizures, and seizures lasting for many days. Although seizure frequency and neonatal mortality associated with seizures were greatest in very premature infants, the outcome in premature infants who survived was not significantly different from that of term infants.

Diagnosis of neonatal seizure by continuous recording and rapid analysis of the electroencephalogram

Clinical diagnosis of neonatal seizure is difficult and repeated seizures may be unrecognised. To assist in early diagnosis we recorded continuously the electroencephalogram (EEG) of very sick newborns while intensive care continued. In 25 babies at high risk of seizure a continuous record of two channels of EEG, ECG, and respiration was made for periods varying from 11 hours to 16 days. The method employed produced an EEG largely free of movement and electrical artefact which was analysed rapidly using a visual display unit. Electroencephalographic seizure activity was recorded in 20 babies, and continuous monitoring of the EEG allowed earlier recognition of seizure than was possible with clinical observation.

Very early neonatal seizure rate: a possible epidemiological indicator of the quality of perinatal care

The most frequently cited objective of perinatal care is the prevention of mortality and morbidity; but there is no general agreement about the indices which should be used to assess the extent to which this broad objective is being achieved. As mortality and morbidity observed during the perinatal period may reflect pathological processes originating earlier in pregnancy, putative indices of perinatal care should ideally be evaluated in clinical experiments comparing different modes of practice. Also, because perinatal practice can affect mortality and morbidity in a reciprocal manner, it is important to define indices of both mortality and morbidity. Morbidity indices should preferably be based on neonatal clinical signs which are both unambiguous and strongly predictive of later morbidity. We propose that the frequency of neonatal seizures beginning within 48 h of birth should be considered as an index which may meet these criteria in respect of full-term babies.

Neonatal seizures and subsequent epilepsy

Neonatal findings and evolutionary courses of epileptic seizures were described in newborns who had seizures during the neonatal period and later developed epilepsy. Neonates with CNS dysgenesis ran the highest risk (80%) for subsequent epilepsy. About 30% of those who suffered from perinatal hypoxia and/or intracranial birth injury and 30% of those who had meningitis developed subsequent epilepsy. In perinatal brain injury, those who developed epilepsy showed more abnormal neurological and electroencephalographic findings than those who did not. The more abnormal the neonatal background EEG, the more frequently epileptic fits developed later. There was no such relationship in CNS dysgenesis. Myoclonic seizures were associated with the most severe brain damage. Newborns who later displayed West syndrome had also very abnormal neonatal EEG whereas those who manifested other types of fits more often had less abnormal neonatal EEGs. In West syndrome, hypsarrhythmia was preceded by focal or multifocal spikes, and closely temporally related with the onset of spasms, but there was a variety of intervals between the onset of clinical fits and EEG spikes in generalized or focal motor seizures.

Neonatal convulsions treated with continuous, intravenous infusion of diazepam

Eight patients born at term in the years 1974-76, with neonatal convulsions due to severe perinatal asphyxia, were treated for 6-11 days with continuous intravenous infusion of diazepam. Doses of 1.0-1.5 mg per hour (mg/h) were usually required to stop the convulsions. In one infant 2.75 mg/h was needed. During the treatment, all infants had measurable serum concentrations of diazepam, half of them above 35 mumol/1. The convulsions stopped in all eight infants, and did not return after discontinuation of the infusion. Side-effects were noted in all infants, but they were all able to breathe adequately. At follow-up the psychomotor development was normal in all cases and there were no signs of neurological disorders, except in one patient, in whom mild epilepsy was observed. Continuous infusion of diazepam should be given in doses of at least 1 mg/h (corresponding to around 0.3 mg/kg h) to stop convulsions in full-term infants efficiently and should be increased under close supervision and with monitoring of respiration and heart rate until treatment is effective.

Seizures in the Nigerian neonate: perinatal factors

A prospective study of 55 infants with neonatal seizures admitted to the Special Care Baby Unit of the University of Benin Teaching Hospital over a 5.5-year period revealed that perinatal asphyxia and hypoglycemia were the principal aetiologic factors in about 71% of the cases. The most frequently encountered seizure types were unilateral clonic (51.5%). Generalized clonic and massive generalized myoclonic seizures were found in 14 (25.5%) and seven (12.7%) cases, respectively, and subtle seizures in three. The overall incidence was 3.5/1000 live births, with a preponderance of male infants in the seizure population, among whom preterm infants were significantly more common. The mortality, (34.5%) was closely related to the etiology. Since the associated adverse perinatal events are largely preventable, improved prenatal and perinatal health care delivery should lead to a decline in the frequency of neonatal seizures.