Cause of neonatal convulsions. Towards more precise diagnosis

Perceived causes and diagnosis of febrile convulsion in selected rural contexts in Cape Coast Metropolis, Ghana

BACKGROUND

Febrile convulsion (FC) is a common seizure disorder among children aged 9 months to 5 years. It is usually benign and self-limiting with favourable prognosis. However, in Ghana, FC is commonly perceived as "not for hospital" and widely diagnosed and managed at home based on several beliefs and practices which are limited in related literature.

OBJECTIVE

This study explored the perceived causes and diagnosis of FC in selected rural communities in the Cape Coast Metropolis, Ghana.

METHODS

A descriptive phenomenological study design underpinned the study at five selected communities located not more than 2 Kilometres from the University of Cape Coast Hospital. Purposive and snowball sampling techniques were used to interview 42 participants made up of 27 parents, two grandmothers, seven registered traditional health practitioners, four herbalists, and two faith healers in the communities. The data was analysed using QSR NVivo 12.

RESULTS

Three perceived causes of FC were identified - biological, social/behavioural, and spiritual. Biological causes include genetic abnormalities and other underlying health conditions. The behavioural factors include poor childcare practices and nutrition. Spiritual causes include harm caused by evil spirits. The diagnosis of FC were observed prior, during and after FC attack, and these includes high body temperature, extreme body jerking, and disability outcomes respectively.

CONCLUSION

The perceived causes of FC are interplay of complex natural, social and spiritual factors that were deep-rooted in local socio-cultural beliefs and FC experiences. Unlike the attack stage, pre-attack diagnosis were usually missed, or misconstrued to mean other health conditions. These findings indicate the need to intensify maternal and child health (MCH) education programmes on FC in the study area through improved primary healthcare.

Neonatal Seizures and Purinergic Signalling

Neonatal seizures are one of the most common comorbidities of neonatal encephalopathy, with seizures aggravating acute injury and clinical outcomes. Current treatment can control early life seizures; however, a high level of pharmacoresistance remains among infants, with increasing evidence suggesting current anti-seizure medication potentiating brain damage. This emphasises the need to develop safer therapeutic strategies with a different mechanism of action. The purinergic system, characterised by the use of adenosine triphosphate and its metabolites as signalling molecules, consists of the membrane-bound P1 and P2 purinoreceptors and proteins to modulate extracellular purine nucleotides and nucleoside levels. Targeting this system is proving successful at treating many disorders and diseases of the central nervous system, including epilepsy. Mounting evidence demonstrates that drugs targeting the purinergic system provide both convulsive and anticonvulsive effects. With components of the purinergic signalling system being widely expressed during brain development, emerging evidence suggests that purinergic signalling contributes to neonatal seizures. In this review, we first provide an overview on neonatal seizure pathology and purinergic signalling during brain development. We then describe in detail recent evidence demonstrating a role for purinergic signalling during neonatal seizures and discuss possible purine-based avenues for seizure suppression in neonates.

Variability in Preferred Management of Electrographic Seizures in Neonatal Hypoxic Ischemic Encephalopathy

BACKGROUND

Seizures may cause added harm in neonates with hypoxic-ischemic encephalopathy (HIE). Specific recommendations about seizure treatment in this context are lacking. We sought to determine the scope of practice regarding management of non-status epilepticus electrographic-only seizures in this setting.

METHODS

A case-based survey was distributed to members of the Child Neurology Society. Providers were asked about their preferred management strategy for sequential clinical scenarios.

RESULTS

A total of 177 child neurologists responded to the survey. Seventy-seven percent of providers would treat 20 seconds or less of electrographic seizure activity. In a neonate with mild HIE and an electrographic-only seizure, there was no agreement among providers regarding whether to start maintenance therapy in addition to a one-time anti-seizure drug load. In a neonate with moderate HIE on phenobarbital for early electro-clinical seizures, most providers would escalate treatment for ongoing electrographic-only seizures by increasing phenobarbital dosing. In a neonate with severe HIE complicated by status epilepticus on phenobarbital who subsequently develops recurrent electrographic-only seizures, providers varied substantially in their management preferences. For all three cases, 75% to 85% of providers would not change their management preferences based on the absence of a clinical correlate with the electrographic seizure.

CONCLUSIONS

We found marked variability among providers regarding preferred management of non-status epilepticus electrographic-only seizures after HIE. Our results identified specific aspects of electrographic-only seizure management in neonatal HIE where there is limited consensus. These discrepancies may serve as opportunities for future investigation.

Recent advances in neonatal seizures

Neonatal seizures are the most important indicators of underlying brain injury. Seizures in a neonate are different from seizures in older children in many aspects including clinical presentation and etiology. The neonatal brain is immature and tends to have a decreased seizure threshold. Neonatal seizures are classified, based on their presentation as, clinical seizures, electroclinical seizures and electroencephalographic seizures; based on the pathophysiology as epileptic and nonepileptic seizures; and also on the basis of the etiology. Hypoxic ischemic encephalopathy is the leading cause of neonatal seizures, followed by intracranial hemorrhage, metabolic causes such as hypoglycemia and hypocalcemia, intracranial infections and strokes. Neonatal epilepsy syndromes are rare. Electroencephalography (EEG) is the gold standard for diagnosis. Amplitude integrated EEG (aEEG) is also used for continuous monitoring. The approach to management consists of initial stabilization of the neonate followed by treatment of potentially correctable injurious processes such as hypocalcemia, hypoglycemia and electrolyte disturbances, etiology specific therapies and antiepileptic drug (AED) therapy. Phenobarbital remains the first line AED therapy. Pharmacokinetic data on newer drugs is limited. Prognosis depends on the etiology, seizure type, neurological examination at discharge and EEG. Long term neurodevelopmental follow up is essential for babies with neonatal seizures.

Electrographic seizures are associated with brain injury in newborns undergoing therapeutic hypothermia

OBJECTIVE

Seizures are common among newborns with hypoxic-ischaemic encephalopathy (HIE) but the relationship between seizure burden and severity of brain injury among neonates receiving therapeutic hypothermia (TH) for HIE is unclear. We tested the hypothesis that seizure burden is associated with cerebral tissue injury independent of amplitude-integrated EEG (aEEG) background activity.

STUDY DESIGN

Term neonates undergoing 72 h of TH at four centres were selected for study if they had continuous aEEG and MRI. The aEEG with corresponding 2-channel raw EEG (aEEG/EEG), was classified by severity of background and seizure burden; MR images were classified by the severity of tissue injury.

RESULTS

Of 85 neonates, 52% had seizures on aEEG/EEG. Overall, 35% had high seizure burden, 49% had abnormal aEEG background in the first 24 h and 36% had severe injury on MRI. Seizures were most common on the first day, with significant recurrence during and after rewarming. Factors associated with severe injury on MRI were high seizure burden, poor aEEG background, 10 min Apgar and the need for more than one anticonvulsant. In multivariate logistic regression, high seizure burden was independently associated with greater injury on MRI (OR 5.00, 95% CI 1.47 to 17.05 p=0.01). Neither aEEG background, nor 10 min Apgar score were significant.

CONCLUSIONS

Electrographic seizure burden is associated with severity of brain injury on MRI in newborns with HIE undergoing TH, independent of degree of abnormality on aEEG background. Seizures are common during cooling, particularly on day 1, with a significant rebound on day 4.

Epidemiology and aetiology of neonatal seizures

Neonatal seizures constitute the most frequent and distinctive neurological symptom in the neonatal period. Seizures in the neonatal period differ considerably from those observed later in life with respect to their aetiological profile and clinical presentation. In addition, the aetiological profile in preterm infants is different from that seen in term infants. Hypoxic-ischaemic encephalopathy is the most frequent cause of neonatal seizures in term babies followed by focal ischaemia (stroke), cerebral malformations and metabolic disturbances. In preterm neonates, intraventricular haemorrhage and infections cause most of the seizures reported in this group. Better neuroimaging techniques have reduced the number of undiagnosed cases, and the institution of newer neuroprotective strategies has influenced the outcome.

Outcome following neonatal seizures

Neonatal seizures are the most common manifestation of neurological disorders in the newborn period and an important determinant of outcome. Overall, for babies born at full term, mortality following seizures has improved in the last decade, typical current mortality rates being 10% (range: 7-16%), down from 33% in reports from the 1990s. By contrast, the prevalence of adverse neurodevelopmental sequelae remains relatively stable, typically 46% (range: 27-55%). The strongest predictors of outcome are the underlying cause, together with the background electroencephalographic activity. In preterm babies, for whom the outlook tends to be worse as background mortality and disability are high, seizures are frequently associated with serious underlying brain injury and therefore subsequent impairments. When attempting to define the prognosis for a baby with neonatal seizures, we propose a pathway involving history, examination, and careful consideration of all available results (ideally including brain magnetic resonance imaging) and the response to treatment before synthesizing the best estimate of risk to be conveyed to the family.

Clinico-etiological and EEG profile of neonatal seizures

OBJECTIVE

To evaluate clinical, etiological and EEG profile of neonatal seizures.

METHODS

In all the neonates enrolled in the study baseline information recorded was sex, gestational age, weight, ponderal index etc. Clinical profile of seizure episode included age at onset of seizure, type and duration of seizure, associated autonomic changes, medication given, response time to medication and possible cause. Relevant maternal history including antenatal and peripartum history was recorded. Relevant history and examination of newborn were noted. Essential investigations done in all subjects included blood glucose, serum calcium, serum sodium and arterial pH. USG cranium and EEG were done at earliest in all the subjects wherever feasible. Additional investigations were done as guided by history, physical examination and essential investigations.

RESULTS

Ninety babies with clinical seizures were enrolled into the study over one year period with an overall incidence of 1.17% (0.69% in term babies and 6.14% in preterm babies). Abnormal EEG's were found in one third cases out of 60 EEG's done in 90 babies. 26.7% of babies with perinatal asphyxia had abnormal EEG's (8/30). While 60% of babies with HIE II had abnormal discharges, background activity was suppressed in 66.66% EEG's in babies with HIE III.

CONCLUSIONS

Overall incidence of neonatal seizures was 11.7/1000 live births, majority being preterm very low birth weight babies before 5 days of life. Perinatal asphyxia was responsible in 44.44% babies followed by metabolic abnormalities (23.33%). EEG abnormalities were present in 33.34% babies.

The epidemiology of cerebral palsy in term infants

Half of cerebral palsy (CP) arises in infants of normal birthweight; yet, many fewer studies seek to identify risk factors for CP in term and near-term infants than in those born very prematurely. There has been no net decrease in the prevalence of CP in term and near-term infants over recent decades. Potentially asphyxiating birth complications account for a small minority of CP cases. Recent studies suggest that disorders of coagulation and intrauterine exposure to infection or inflammation are associated with risk of CP, and that both can be accompanied by signs of neonatal encephalopathy, the best available predictor of CP in term neonates. Therapeutic interventions directed at preventing interruption of oxygen supply have not been shown to reduce the occurrence of CP. There have not yet been studies examining whether medical interventions directed at infection or coagulation disorder can reduce the frequency of CP.

The clinical conundrum of neonatal seizures

There is increasing evidence that neonatal seizures have an adverse effect on neurodevelopmental progression and may predispose to cognitive, behavioural, or epileptic complications later in life. However, given the uncertainty about the efficacy and toxicity of the commonly used anticonvulsants, when and how aggressively to treat such seizures is a difficult decision.

Sonographic diagnosis of intracranial hemorrhage and periventricular leukomalacia in premature African neonates

Transfontanelle ultrasound (US) was done prospectively and analyzed for intra-cranial hemorrhage (ICH) and periventricular leukomalacia (PVL) in 110 premature infants. The babies were divided into two subgroups according to their birth weights (BW): those with BW of 1500 g or less (n = 93) belonged to subgroup A while babies of BW between 1500 and 2500 g (n = 17) were placed in subgroup B. Overall incidence of ICH and PVL was 24.5 and 26.4%, respectively in the 110 cases studied. Under subgroup A, 26/93 (28.0%) cases had ICH while 22/93 (23.7%) cases had PVL. In subgroup B, 2/17 (11.8%) cases had ICH while PVL was noted in 7/17 (41.2%) cases. These results show that premature African children have a lower incidence of ICH but a higher incidence of PVL compared to babies from temperate regions. Genetic and environmental factors are probably responsible for these variations in the occurrence of both diseases in population groups from different geographical locations.

Foetal supraventricular tachycardia and cerebral complications

We report on two newborn infants with foetal tachycardia and cerebral lesions. Using foetal echocardiography, the diagnosis of supraventricular tachycardia in a structurally normal heart was made at 28 and 37 weeks of gestation, respectively. One infant had a 3 week period of foetal tachycardia and hydrops before successful pharmacological cardioversion. Even several weeks after a term birth he remained hypotonic and needed gavage feeding. A computed tomography (CT) scan demonstrated cerebral lesions indicating a vascular origin. A possible thrombus was found in the heart. The other infant converted to sinus rhythm during birth by Caesarean section on the day after diagnosis. He had convulsions at the second day of life. On CT scan an infarction was found. The observations of this report suggest that cerebrovascular complications to foetal arrhythmias are more common than previously observed and should be considered when managing cases of foetal tachycardia.

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.

Ultrasonographic findings in thalamus and basal ganglia in term asphyxiated infants

Three severely asphyxiated term neonates demonstrated bilateral hyperechogenicity in the thalamus and basal ganglia. During evolution, areas of attenuated echogenicity appeared in these structures at the same time as periventricular cysts were evident in 2 patients with coexistent periventricular leukomalacia. All 3 patients developed ventricular dilatation; in the 2 patients with periventricular leukomalacia, the ventricular border was irregular in the outer (dorsal) margin, and interhemispheric fissures were widened as a manifestation of cerebral atrophy. Furthermore, the thalamic inner (ventral) margins of the lateral ventricles were irregular in all 3 patients. This previously unrecognized finding points to a particular form of cerebral atrophy localized in the gangliothalamic region that contributes to the development of ventriculomegaly. The reported sonographic sequence implies profound damage in the thalamus and basal ganglia in asphyxiated infants which undoubtedly has contributed to the poor outcomes of our patients.

Cerebral infarcts and seizures in the neonate

A retrospective analysis was performed on 54 infants who suffered perinatal hypoxic-ischemic insults and came to autopsy, in an attempt to assess the association of cerebral infarcts with seizures. Fifty infants had several types of cerebrovascular lesions, including intraventricular hemorrhage (32 cases), periventricular leukomalacia (24), ischemic neuronal necrosis (18), pontosubicular necrosis (12), cerebral infarct (9), and cerebellar hemorrhage (7). Of these infants, nine had electroencephalographic seizures. Among a variety of cerebrovascular lesions, cerebral infarcts represented the single lesion most highly correlated with seizures. The incidence of seizures in infants with cerebral infarcts (44%) was significantly higher than with other types of vascular lesions.

Fifth day fits in the newborn

During the 1970s, there was an epidemic of neonatal convulsions occurring in apparently normal babies during the fourth and fifth days of life. This syndrome was noted in France as well as in Australia. A study was undertaken to review the King George V Hospital (KGV) experience with these 'fifth day fitters'. All cases of neonatal convulsions at KGV during the years 1972-85 were reviewed. A total of 94 cases of fifth day fits occurred during this period, accounting for 57% of all neonatal convulsions occurring during 1972-79. The fits occurred in healthy term infants after an uncomplicated pregnancy. They appeared on the fourth and fifth days of life. The seizures lasted an average of 24 h, were refractory to drug therapy and, despite extensive investigation, no cause was found. The infants were assessed as normal at the time of discharge from hospital. Follow-up of these infants was incomplete. However, from the data available, it cannot be assumed to be a benign entity. The 'fifth day fit' syndrome reached epidemic proportions at a number of maternity units during the 1970s. At KGV, no case has been observed since 1982.

Neonatal stroke: description of patients and investigation into pathogenesis

We report 15 patients with neonatal stroke reviewed retrospectively. Twelve patients had left middle cerebral artery involvement--the same ratio observed in 36 previously reported patients with strokes. We studied 20 normal neonates prospectively to determine whether a difference in flow velocity could be detected between the left and right middle cerebral arteries; pulsed Doppler ultrasound, which compared both velocities, demonstrated no significant difference.

Primary thalamic and caudate hemorrhage in term neonates presenting with seizures

Two previously well term neonates who presented with seizures are described: one with thalamic hemorrhage and the other with thalamic and caudate hemorrhage. These 2 patients were the only neonates found with thalamic hemorrhage in a review of 54 term infants with intracranial hemorrhage at The Hospital for Sick Children over a 10 year period (1976-1986). Partial seizures occurred at 5 and 7 days after birth and were easily controlled. Prognosis was generally good in these 2 patients, as well as in 4 previously reported patients.

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.

Intrapartum fetal monitoring

From the fetal viewpoint, labour is a prolonged contraction stress test which most pass without incident. Labour also represents the obstetrician's last opportunity to influence perinatal outcome and ensure that those fetuses who have suffered chronic hypoxia antenatally are recognized promptly, so that labour is supervised in a way that does not place them at increased risk of either death or birth asphyxia. In the case of the fetus who enters labour healthy, with normal reserves, labour is managed with the same aim in mind, but with the foreknowledge that visualization of a normal volume of clear amniotic fluid and reasonable duration of labour makes the development of hypoxia and asphyxia unlikely. Those at increased risk of hypoxia should be monitored electronically, but, for the remainder, intermittent auscultation is satisfactory until labour lasts in excess of 5 hours, or if the patient requires oxytocin, or if an epidural is placed. If EFM is used, then it is important to provide adequate education in trace interpretation, with particular emphasis on the importance of short-term variability. Widespread use of EFM has provided us with an immense amount of knowledge about fetal physiology, but it is critically important for the practising obstetrician to understand that, in the low-risk patient, EFM is not more effective than IA in preventing death from asphyxia, that EFM does protect against asphyxial seizures, but that widespread use of the technique has not been associated with a significant reduction in the population of permanently handicapped infants. This information is particularly relevant in developing nations where money spent on sophisticated monitoring equipment might be better spent in other areas. From the maternal point of view, intensive fetal monitoring has profound implications by virtue of its usual effect on incidence of Caesarean birth, although the Dublin trial results, with regard to incidence of Caesarean section, emphasize the importance of considering intrapartum fetal monitoring as just one part of the overall supervision of labour. Finally, it must be emphasized that the method of fetal monitoring chosen may be strongly influenced by factors other than scientific evidence, as in the United States where the medicolegal climate is such that failure to rigorously document absence of fetal distress/true birth asphyxia may result in a harrowing lawsuit. It is a position this author has developed considerable sympathy with in recent years.