Seizures and non-epileptic events

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8.3 Seizures and non-epileptic events

Padraic Grattan-Smith

Essentials

1 Seizures are the most common life threatening emergency presentation to EDs requiring immediate management.
2 The diagnosis of a seizure is based on a careful history.
3 There are many paroxysmal events or ‘funny turns’ in children, which can mimic seizures.
4 A bedside dextrostix should be performed on the child who is having a seizure. First-ever seizures should have blood sent for formal glucose, electrolytes, calcium, magnesium and phosphate levels.
5 The acute management of the child having a seizure involves supporting airway and breathing and the graduated use of antiepileptic drugs to terminate the seizure.
6 Parental reassurance and education regarding seizures, BLS and safety issues are an important facet of management in the child presenting with a first convulsion.

Introduction

An epileptic seizure can be defined as a disturbance in neurological function, resulting from uncontrolled excessive neuronal activity in the central nervous system.

The subject of seizures and their differential diagnosis is large. This chapter provides essential information that may be useful in formulating diagnosis and treatment in the emergency department (ED). There is insufficient space for a detailed discussion of the role of the electroencephalogram (EEG) and other investigations.

General comments

There are a number of conditions that must always be considered in children experiencing ‘unusual events’. Hypoglycaemia can cause both partial and generalised seizures. It may also ‘illogically’ produce focal neurological signs. Abnormalities of electrolytes, calcium, magnesium and phosphate can present in a similar fashion. Cardiac arrhythmias associated with prolonged QT interval may cause epileptic seizures that seem to follow the arrhythmia. Sudden loss of consciousness during, or immediately after, intense exercise or associated with strong emotion, raises the possibility of an underlying cardiac cause. A family history of premature unexplained sudden death in a young relative should also raise this possibility.

Some variants of migraine may be difficult to distinguish from seizures. Acute confusional migraine often follows minor head trauma. The episodes may last for a number of hours. The child is ‘concussed’, confused and often vomiting. Basilar artery migraine is associated with confusion or loss of consciousness and brainstem symptoms and signs. Neither diagnosis should be made at the first presentation and without further investigation. On the other hand, occipital epilepsy can cause vomiting, visual loss and severe headache. The presence of tonic eye deviation early in the event is a strong clue that this is a seizure rather than migraine.

Pseudoepileptic seizures and Munchausen’s syndrome by proxy always need to be considered in the differential diagnosis of atypical epileptic seizures. However, the diagnosis is often difficult and the ED is usually not an appropriate setting to make a confident diagnosis of either of these conditions.

Classification of seizures

Seizures are conceptually divided into generalised seizures where the onset is from all brain regions simultaneously and partial seizures, where the seizure arises from one area in the brain. In simple partial seizures there is no alteration of consciousness. With complex partial seizures, alteration of consciousness occurs. Partial seizures may spread and become secondarily generalised.

Status epilepticus is said to occur where a seizure lasts more than 30 minutes or there is incomplete recovery between seizures over this time period. In practical terms, any child who arrives in the ED still fitting, should be regarded as a medical emergency. Status epilepticus can occur in both convulsive and non-convulsive forms.

Febrile seizures

Febrile convulsions are not regarded as a form of epilepsy but are discussed because of their frequent presentation to EDs. Typically they occur in children between 6 months and 6 years of age. They are common, affecting around 3% of children. Most children who have febrile convulsions have only one, but 25–30% will have a recurrence. The risk of recurrence is greater in infants less than 12 months, where it may be as high as 50%.

Febrile convulsions most commonly occur in the setting of viral illnesses such as an upper repiratory tract infection, pharyngitis, gastroenteritis, or an exanthem such as roseola infantum. Much less commonly, pneumonia or a urinary tract infection may be the underlying cause. Febrile seizures typically occur relatively early in the course of an infectious illness and sometimes the convulsion is the first sign that the child is unwell.

Most febrile seizures are generalised and brief, lasting less than a few minutes. The child returns to normal after a short (usually less than 30 minutes) postictal period. The seizures may be clonic, tonic–clonic or atonic where the child may simply seem to stop breathing. Examination should confirm the presence of a fever, identify the source of the fever, and exclude signs of central nervous system (CNS) infection or of a focal neurological process. Most children with an uncomplicated febrile seizure who have completely recovered and have a clear source of infection require no blood tests or other investigations.

Prolonged (lasting >10 minutes) and complicated (focal, multiple) febrile seizures can occur. Underlying meningitis/encephalitis must always be considered in the child who fails to return to normal, has multiple or prolonged seizures or has residual neurological signs. The threshold to perform a cerbrospinal fluid (CSF) examination is lower when the child is less than 12 months of age or has been on antibiotics, which may mask the usual signs of meningism. However, lumbar puncture can be dangerous in the child with focal signs such as a hemiparesis or if there has been a rapid deterioration in conscious level or an abnormality of respiratory rhythm. Consultation with senior colleagues is advised if there is doubt about the safety to perform a lumbar puncture.

Children with seizures are seen in the ED in two broad settings:

The child who is seen after an event. Was this a seizure?
The child who is still fitting.

The child seen after the event

History

The diagnosis of seizures is based almost entirely on the history.

The parents or any witnesses of the event should be taken through the episode systematically. An exact description of what took place is crucial in making a correct diagnosis. What was the child doing when it started? What was the very first sign of a problem, and what followed? If abnormal movements were present, did they principally involve one side of the body? How long did the event last? What was the child like afterwards? How long before the child was back to normal? Was there any faecal or urinary incontinence or tongue biting? Was there any apnoea or colour change?

Witnessing a sudden loss of consciousness in a child is an extremely upsetting event for any observer, particularly the parents. Many parents report that they thought their child had ‘stopped breathing’ and commenced various resuscitation techniques. There are obvious limitations to the history, but it remains the single piece of information most likely to provide a diagnosis. It is also worth talking to the verbal child about what happened. Even young children can sometimes give very helpful accounts if spoken to soon after the event.

It is important to establish whether there may have been provocative factors, such as sleep deprivation, a febrile illness, head trauma or potential exposure to epileptogenic medications. A past history of similar events should be sought. It is also important to ask about a family history of seizures or unusual turns and to review the child’s developmental milestones.

Examination

The physical examination is often normal, but it must be carefully performed, looking for fever, evidence of intercurrent illness and abnormal neurological signs. Other important diagnostic clues include a Todd’s paralysis, skin lesions of tuberous sclerosis or morphological features of a chromosomal disorder or other underlying neurological abnormality associated with a seizure disorder. The finding of lateral tongue trauma or incontinence supports a suspicion of seizure when the diagnosis is unclear. The febrile child needs to have an underlying meningitis or encephalitis excluded.

In infants, the sudden onset of frequent seizures and failure to regain consciousness is a common presentation of child abuse and a careful retinal examination must be performed, looking for retinal haemorrhages.

Differential diagnosis

Tonic–clonic seizures, myoclonic seizures and clonic seizures, in general, can occur at any age. They are well described in standard textbooks and will not be discussed here except to discourage the tendency to loosely label any event with loss of consciousness as a ‘tonic–clonic’ seizure.

Although there is overlap, it is helpful to approach the problem in terms of age of presentation. For neonatal seizures refer to Chapter 2.6.

Infancy

Seizure types

Infantile spasms

Typically take the form of ‘salaam’ seizures. There is characteristic sudden flexion of the arms, head and trunk in a brief spasm. Asymmetrical or extensor spasms can occur. The characteristic feature of established infantile spasms is that the episodes occur in runs (clusters) which can continue for 10 minutes or more. In the early phases, the spasms may be mild and relatively infrequent, making diagnosis difficult.

Lennox–Gastaut syndrome

In this syndrome there are multiple seizure types, including atypical absences, myoclonic seizures, drop attacks, nocturnal tonic seizures and generalised tonic–clonic seizures. In the early phases, which can be seen in late infancy, the child may present with atypical absences. These have somewhat slower onset than typical absences and there may be obscuration rather than complete loss of consciousness. Great caution should be taken with any child presenting in the first 2 years of life with ‘absences’, as this may be an early manifestation of Lennox–Gastaut syndrome.

Complex partial seizures in infancy

May present as episodes of altered consciousness, with autonomic symptoms and also with apnoea. An underlying tumour (most often in the temporal lobe) may cause this type of seizure.

Non-epileptic events of infancy

The following events can mimic seizures in young children and are usually distinguished by a careful history.

Breath-holding spells

These are always provoked by an unpleasant stimulus. This is usually minor trauma, e.g. a bump on the head, but the child being scolded or frustrated may provoke them. Somewhat arbitrarily, breath-holding attacks are divided into:

Pallid breath-holding attacks, where after a short cry, the infant loses consciousness, becomes pale and there may be tonic stiffening.
Cyanotic breath-holding attacks, where after vigorous crying, there is breath-holding in expiration and loss of consciousness.

As in syncopal episodes there may be brief clonic jerking after an episode. The story of provocation is usually clear, but at times there can be diagnostic confusion, for example, when a child who is playing happily is found unconscious on the floor and no precipitating event was observed.

Benign neonatal sleep myoclonus

This is characterised by myoclonic jerks, which can be quite violent and asymmetric, but are confined to sleep. The infant is otherwise normal.

Benign paroxysmal vertigo

Sudden episodes of acute unsteadiness occur without alteration of consciousness. The child typically clutches onto whatever is nearby. The episodes are usually brief, lasting seconds to minutes. The parents may notice nystagmus during an episode. There may be multiple episodes per day.

Shuddering attacks

The infant’s body ‘shivers’ as though cold water had been poured on its back.

Self-stimulatory episodes (‘infantile masturbation’)

These are seen in girls. The thighs are generally clenched tight, with the legs crossed at the ankles. There are pelvic undulatory movements. The infant may look extremely flushed and upset and may be sleepy afterwards.

Stereotypies

There are hand-flapping or other repetitive limb movements. These are usually repeated in exactly the same way each time. Although common in children with autism, they also occur in children who are otherwise normal.

Day-dreaming

Is common at all ages in childhood. The child may stare straight ahead and at times not respond to being called.

In daydreaming, stereotypic behaviours and self-stimulatory episodes, the event can usually be immediately stopped by physical interaction with the child, e.g. by tickling them.

Childhood

Seizure types

Absence seizures

Are usually brief staring spells characterised by a sudden loss of consciousness and an abrupt end to the seizure. There is no post-ictal period. With longer absences, automatisms may occur. The events usually last less than 10 seconds, and multiple episodes may occur per day.

Complex partial seizures

There may be an aura (actually a partial seizure), a more prolonged episode of altered consciousness in which the child may be partially responsive and a post-ictal period characterised by drowsiness and a desire to sleep.

Benign focal epilepsy of childhood

In its typical form, presents with the child awaking from sleep at around 2–4 a.m. making a ‘glugging’ or ‘clucking’ noise. This is followed by a clonic seizure involving one side of the body, including the face. The child may be awake during the seizure and find it very frightening. Not uncommonly, this seizure becomes secondarily generalised.

Nocturnal frontal lobe seizures

Are rare but may be mistaken for night terrors and ‘pseudoseizures’. Seizures should be considered if there are multiple stereotyped events occurring in the one night, if the episodes are very brief or if they occur only in the second half of the night.

Non-epileptic events of childhood:

Night terrors

Usually occur within the first few hours of the child going to sleep. Typically the child screams and is found sitting up in bed with widely dilated pupils and appears to be extremely fearful. This may last for half an hour or more. The child is eventually comforted and goes off to sleep. The next morning the child has no memory of the event.

Nightmares

In contrast, these usually occur in the second half of the night. The child goes into the parent’s bedroom afraid because of a ‘bad dream’. The child usually has a good memory of the dream, although he/she may not want to discuss it.

Paroxysmal kinesigenic dyskinesia

Brief episodes of dystonic or choreoathetoid movements involving the limbs are provoked by sudden bursts of exercise. There is no alteration of consciousness.

Late childhood and adolescence

Seizure types

Juvenile myoclonic epilepsy

This usually develops in the early teenage years. Typically there are myoclonic jerks in the morning soon after awakening. These may not be mentioned to the parents. The first presentation is often with an early morning generalised tonic–clonic seizure. A history of early morning myoclonus should always be sought in this situation.

Non-epileptic events

Syncope

Is usually a vasovagal response provoked by a stressful situation, such as seeing blood or standing for a prolonged period in hot weather. There is a feeling of light-headedness, nausea and then a progressive fading out of vision. As mentioned above, there may be brief stiffening and clonic jerks in the course of syncopal episodes. Unusual forms of syncope in adolescence include ‘stretch syncope’ provoked by neck hyperextension and shoulder abduction while stretching and ‘hair grooming syncope’, which seems to be provoked by strong pulling of the hair while combing or brushing. Children with intellectual handicap may repeatedly provoke episodes of loss of consciousness by hyperventilating and then performing the Valsalva manoeuvre.

Rage attacks

These consist of sudden episodes of directed anger, usually provoked by being thwarted in some way. A careful history will usually differentiate a rage attack from non-directed aggression, which can occur in the post-ictal state. This usually occurs when a patient in a confused post-ictal state is restrained or surrounded by a crowd of people.

The child who is still fitting

The child with convulsive status epilepticus

When a child is fitting on arrival at the ED, the seizure is likely to have continued for at least 15 minutes. There is a risk of brain damage or death if the seizure is not rapidly controlled and respiration appropriately supported. There needs to be a clear plan for the immediate management of the convulsing child. The child should be taken directly to the paediatric resuscitation area with ready access to anaesthetic and airway resuscitation facilities.

Airway, breathing and circulation need to be assessed and simultaneously managed. The child should receive high-flow oxygen via mask or assisted by bag and mask, if ventilation is inadequate. Basic airway manoeuvres and suctioning may be required. Oxygen saturation should be monitored continuously. Intravenous access should be gained and a Dextrostix checked immediately to exclude hypoglycaemia. Blood should be taken for glucose, electrolytes, calcium, magnesium and phosphate and full blood count. Children on maintenance anticonvulsants should have their drug level taken.

At the same time, a history should be rapidly obtained regarding:

• the duration of the seizure;
• previous episodes (and if there is a particular drug most likely to be effective);
• precipitating events;
• medications the child is taking;
• whether drugs have already been given for the seizure;
• the presence of underlying neurological problems.

Drug therapy

If the child has received no treatment for the seizure prior to arrival, the following approach is suggested.

First line

Initial treatment is with benzodiazepines, which are rapidly acting, using intravenous (IV) diazepam 0.25 mg kg–1 or IV midazolam 0.15 mg kg–1. If the seizure has not stopped within 5 minutes the dose can be repeated. The potential side effects of respiratory depression or apnoea need to be anticipated.

Second line

If after another 5 minutes the fit continues, IV phenytoin 20 mg kg–1 as an infusion over 30 minutes or IV phenobarbital 10–15 mg kg–1 as an infusion over 30 minutes should be given. These ‘second-line’ agents need to be given slowly by intravenous infusion, and therefore will take time to control the seizure. If continued seizure activity is causing respiratory compromise or it is felt their severity may result in brain injury, it may be necessary to use further benzodiazepines and be prepared to support respiration or to proceed to use barbiturates, which require intubation.

Third line

If there has been no response after a further 5 minutes, thiopental 5 mg kg–1 and intubation using rapid sequence induction, is the next step. The decision to intubate to control a seizure needs to involve consideration not only of the length and severity of the seizure but also the degree of respiratory embarrassment to the child. Mild seizure activity that is not compromising a child can be tolerated longer than a major convulsion that is impairing oxygenation. These children will need to be subsequently managed in a paediatric intensive care unit.

There are almost endless variables in this situation. If intravenous access is a problem, midazolam 0.15 mg kg–1 may be given intramuscularly, or into the nose or buccal space, or diazepam 0.5 mg kg–1 may be given rectally. Intraosseous injection can be used. If the child has already received a benzodiazepine beforehand, a second dose may be given on arrival, followed by phenytoin as it is less likely to cause respiratory depression than the combination of phenobarbitone and a benzodiazepine.

In a severely handicapped child who has frequent bouts of status epilepticus where there is a desire to avoid intubation, paraldehyde 0.4 mL kg–1 rectally may be tried if there has been no response to benzodiazepines, phenytoin or phenobarbital.

Absence, atypical absence and complex partial status are much less common than convulsive status but should be considered in children who are obtunded or have bizarre behaviour without obvious cause. If there is doubt an EEG should be performed. If an EEG is unavailable and CNS infection and metabolic causes have been excluded, ‘waking up’ soon after an IV dose of a benzodiazepine is a useful diagnostic clue of ‘non-convulsive’ status.

Investigations

These depend on the clinical setting but some general rules apply.

Blood tests

All children having a seizure should have a bedside Dextrostix followed by a formal blood glucose to exclude hypoglycaemia. At the same time full blood count, electrolytes, calcium, magnesium and phosphate levels should be checked in order to exclude a metabolic cause. These are exceedingly rare beyond the infant age group in the child who has returned to normal and the yield is negligible, unless there are other clues to promote an electrolyte disturbance.

Neuroimaging

As a general rule, patients with focal seizure or examination findings, features suggesting raised intracranial pressure or seizures in the setting of trauma, should have urgent neuroimaging. The computerised tomography scan of the brain has the advantage of relative ease of access but it should be remembered that the magnetic resonance scan is a better test in almost all instances except traumatic brain injury.

EEG

An urgent EEG is very useful in cases where convulsive status epilepticus has been treated but the patient remains unconscious and there is a suspicion of continuing non-convulsive status. It is also very helpful in the child presenting with an altered state of consciousness and absence or complex partial status is suspected. In the child who has recovered from a brief seizure an EEG done soon after presentation may be useful, e.g. showing focal changes that suggest a secondarily generalised seizure. There is no reason to delay getting an EEG soon after a fit but this will be limited by the resources that are available.

Disposition

Children who have prolonged or multiple seizures, focal seizures, or abnormal neurological examination, or where the diagnosis is unclear, should be admitted for observation and paediatric or neurological review. Children who are having increased frequency of seizures or are known to have prolonged, or clusters of seizures warrant admission and observation until stabilised.

Not all children presenting with an uncomplicated first seizure need to be admitted to hospital. Those who have a first generalised seizure, with normal neurological examination and metabolic work up, can be followed up on an outpatient basis. This is usually best achieved by discussion with a general paediatrician or neurologist colleague to determine the timing of imaging and an EEG and formal review. Other influences on the decision to admit may include the age of the child, parental anxiety and any intercurrent illness issues.

If the event has clearly been a brief seizure, it is important to discuss the nature of this with the parents and provide some reassurance that it has not caused brain damage. First-aid measures should be discussed with the parents so that they have a clear plan should their child have a further seizure at home. The parents should be warned that further seizures can occur. It is important to take care that the child is not in a potentially dangerous situation should this happen. A particular risk is swimming without careful adult supervision. This advice should be reviewed at the organised follow up. Children who are discharged after a febrile convulsion should be reviewed by their local doctor within 24 hours to follow progress and reinforce the safety issues.

Controversies and future directions

Unlike in other countries, the intravenous form of sodium valproate has not been used widely (if at all) in Australia.
In the future, newer intravenous agents such as levetiracetam may come to be increasingly used in the acute management of seizures.
Given the efficacy and safety of midazolam by the IM or IN route, many clinicians argue that there is no place for rectal diazepam, given its impracticality and unpredictable absorption by this route.

Further reading

Chin R.F., Neville B.G., Scott R.C. Meningitis is a common cause of convulsive status epilepticus with fever. Arch Dis Childhood. 2005;90:66-69.

Maytal J., Shinnar S., Moshe S.L., Alvarez L.A. Low morbidity and mortality of status epilepticus in children. Paediatrics. 1989;83:323-331.

Mitchell W. Status epilepticus and acute repetitive seizures in children, adolescents and young adults: Etiology, outcome, and treatment. Epilepsia. 1996;37(Suppl 1):S74-S80.

Sofou K., Kristjansdottir R., Papachatzakis N.E., et al. Management of prolonged seizures and status epilepticus in childhood: a systemic at review. J Child Neurol. 2009;24:918-926.

The Status Epilepticus Working Party. The treatment of convulsive status epilepticus in children. Arch Dis Child. 2000;83:415-419.

Verity C.M., Ross E.M., Golding J. Outcome of childhood status epilepticus and lengthy febrile convulsions: Findings of national cohort study. Br Med J. 1993;307:225-228.

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