RECURRENT SEIZURES IN CHILDHOOD
Pratibha Singhi*
Professor of Pediatrics, PGI Chandigarh Email: psinghi@glide.net.in *
Introduction

Seizures

are a common problem about 10% of people have one seizure in their lifetime, however 50-70% do not have a recurrence. Epilepsy is defined as two or more unprovoked epileptic seizures. Epilepsy occurs in 0.5% of the population and about 60% of epilepsy has its onset in childhood. In this paper only recurrent epileptic seizures are discussed. Seizures that do not require a diagnosis of epilepsy such as febrile seizures are not discussed.

A basic understanding of the

International Classification of seizures

(Table 1) and epilepsy and (Table 2) is essential. Most epileptic seizures in children can be classified into various Childhood Epileptic Syndrome (CES), which consist of common clusters of characteristics such as age seizure type, EEG, and prognosis, which define a unique epilepsy condition. They may have different etiologies. In our country however, CNS infections constitute an important cause of recurrent seizures. These particularly include post meningitic seizures and seizures secondary to granulomas such as Neurocysticercosis (NCC), and tuberculomas. It is important to ensure that one is not dealing with nonepileptic events (NEE), (which may resemble seizures), before approaching a child with recurrent seizures. Some of the common NEEs in childhood are listed in Table 3.
Table 1. SUMMARY OF INTERNATIONAL CLASSIFICATION OF SEIZURES
  • Partial (local focal)


    -

    Simple partial


    -

    Complex partial


    *

    With impairment of consciousness at onset


    *

    Simple partial onset followed by impairment of consciousness


    *

    Partial evolving to generalized tonic clonic


    *

    Complex including those with simple partial onset

  • Generalized [convulsive or non-convulsive]

  • Typical absence and atypical absence

  • Myoclonic, tonic, clonic, tonic-clonic Unclassified

Table 2. INTERNATIONAL CLASSIFICATION OF EPILEPSY AND EPILEPTIC SYNDROME (ICE) (ILAE-REVISED 1989)
  • Localization-related (Focal/local/partial) idiopathic, symptomatic, cryptogenic
  • Generalized
  • Idiopathic, cryptogenic West, LGS
  • Symptomatic - non-specific/specific etiology
  • Undetermined (whether focal or Gen./Both) equivocal
  • Special syndromes
  • Situation related-febrile, isolated status/seizure, metabolic encephalopathy, drug induced, etc.
Table 3. Some Common Non-epileptic Events
  • Syncopal attacks
  • Benign paroxysmal vertigo
  • Complicated migraine
  • Shuddering attack
  • Breath holding spells
  • Tics
  • Night terrors
  • Somnambulism
  • Narcolepsy
  • GER with laryngospasm and apnea
  • Transient ischemic attacks
  • Pseudoseizures/psychogenic

In our country however, CNS infections constitute an important cause of recurrent seizures.
A) Child Epileptic Syndrome (CES)
Most CES are age specific and are often different in neuro-developmentally normal children and in children with neurological abnormalities and developmental delays. Consideration of the (i) age and (ii)

neuro-developmental status of the child

and (iii) the type of seizures, helps in making a presumptive diagnosis of a CES, which can then be confirmed by EEG. Further investigations such as neuro-imaging, metabolic and genetic tests can then be planned depending upon the CES under consideration. Etiologically CES can be classified into idiopathic, cryptogenic or symptomatic depending upon whether there is any identifiable or suspected or known etiology. In certain situations the child may be neuro-developmentally normal, and may show regression after the onset of the CES; the infantile epileptic encephalopathies are severe epilepsies wherein the severe epilepsy is itself associated with an encephalopathic condition. The ILAE Task Force (1997) has suggested that the diagnosis of epilepsy be made in various axes (Table 4).
Table 4. ILAE Task Force on Classification 1997 Axes
  1. Ictal phenomenology
  2. Seizure type
  3. Syndrome
  4. Etiology
  5. Impairment
Some of important CES include
Onset in neonatal period (birth 3 months):

Neonates may have seizures due to various causes, particularly metabolic problems, and hypoxic ischemic encephalopathy. These will not be discussed here.
In otherwise healthy, and neurologically and developmentally normal neonates, the occurrence of multi-focal clonic seizures, indicates either Benign Neonatal Convulsions (BNC) or Benign Neonatal Familial Convulsions (BNFC). If there is a positive family history, consider BNFC; In the absence of family history, consider BNC. One must exclude underlying etiology and follow the neurodevelopment of the baby. BNC are short lived; BNFC may last for 1-6 months. These babies have a normal neuro-developmental outcome and good prognosis. They do not need long term AEDs.

In otherwise healthy, and neurologically and developmentally normal neonates, the occurrence of multi-focal clonic seizures, indicates either Benign Neonatal Convulsions (BNC) or Benign Neonatal Familial Convulsions (BNFC).

Pyridoxine dependency or deficiency must always be excluded in neonates as well as infants.


Ohtahara syndrome and early myoclonic encephalopathy occur in neurologically impaired, or high-risk neonates, with the occurrence of repeated tonic or myoclonic seizures and fragmentary myoclonus. The EEG shows a burst suppression pattern. Progressive neurologic deterioration occurs, and about half the cases die within a few months; survivors have severe disabilities. Most AEDs and steroids are ineffective.

Onset in Infancy (3 months - 2 yrs)
  1. Benign Myoclonic Epilepsy of Infancy (BMEI): This is characterized by myoclonic seizures in otherwise normal infants and toddlers 4 months to 3 years of age. Seizures are brief, and involve mainly the arms and head. Family history of epilepsy is reported in 25-30% cases. The interictal EEG is usually normal. Valproate is the drug of choice and the prognosis is good with a normal neuro-developmental outcome.
  2. Infantile Spasms (IS) West's Syndrome (WS): This is characterized by infantile spasms, neuro-developmental impairment and hypsarrhythmia on EEG. The peak age of onset is between 4-6 months but may occur any time in the first two years of life; 90% of IS begin before 12 months of age. The spasms may be flexor, extensor or mixed, and occur in clusters, generally on awakening. Crying or irritability during or soon after a cluster is often seen.

    Most children are neurologically abnormal. A small number of cases may be idiopathic, some apparently normal children may show regression after the onset of spasms.

    ACTH injections or corticosteroids are generally used. Vigabatrin is used in children with tuberous sclerosis (TS) but also in other symptomatic cases. However its cost and side effects need to be considered. Valporate and nitrazepam have been used particularly for relapses. LTG and TPM are the newer AEDS that are effective in WS.

    ACTH injections or corticosteroids are generally used. Vigabatrin is used in children with tuberous sclerosis (TS) but also in other symptomatic cases.
  3. Severe Myoclonic Epilepsy of Infancy (SMEI) (Dravet Syndrome): This usually starts as prolonged or recurrent febrile seizures in the first year of life in apparently normal children. In the second year, myoclonus starts and later absence; partial and other types of seizures may occur. Child then shows developmental delay and mental deficiency. It is resistant to most AEDs.

Onset in Early Childhood: Certain benign partial epilepsies and absence epilepsy are important in the age group. The important CES include:
  1. Childhood Absence Epilepsy: This is seen most often in school age (4-10 yrs) with a peak at 6-7 years. It occurs in normal children and consists of typically short (absences) seizures lasting 5-30 sec with abrupt onset and cessation, generally frequent, 10-100/day. In 50% cases associated clonic tonic seizures be seen. The EEG shows a normal background with typical bilateral, synchronous, symmetrical spike waves, usually 3 Hz that are precipitated on hyperventilation. Children with typical absences do not need any further investigations. The AEDs of choice are valproate, ethosuximide and LTG, AEDs that may worsen absences such as OXC, CBZ, VGB and TG are contraindicated. The outcome in typical CAE is generally good, and most cases remit by puberty. Patients with atypical absences do not have a good prognosis.
  2. Lennox Gastaut Syndrome: This has an onset from 1-8 yrs, with a peak between 3-5 yrs. It consists of multiple seizure types: tonic, atonic, atypical absence, myoclonic, GTCS, partial. Repeated seizures, and status epilepticus are common. Tonic seizures are most frequent, and cause repeated falls. There is associated mental retardation. The EEG shows abnormal background with slow spike/poly spike-waves 2.5-2.5 Hz; multi-focal abnormalities may be seen.

    Most cases of LGS, are symptomatic with previous CNS insult/epilepsy (60%), West's syndrome (30-40%).

    Treatment: Valproate and Lamotrigine are the drugs of choice. Topiramate has also been reported to be effective. Benzodiazepines such as clonazepam may also be needed. The seizures are resistant to most AEDs, and a complete control is rarely achieved, even with poly-therapy. Ketogenic diet improves seizure control in about a third to half the cases. In spite of polytherapy seizure control is often poor.

Onset in Late Childhood/Puberty
  1. Benign Childhood Epilepsy with centrotemporal spikes BCECT (Rolandic epilepsy): This has an onset from 3-13 years with a peak at 7-9 yrs. It occurs in neurologically normal children with and is characterized by brief, simple partial hemifacial motor seizures with associated somatosensory symptoms. These evolve into GTCs in 25% cases especially during sleep. The EEG shows characteristic blunt high-voltage centrotemporal spikes followed by slow waves. Some physicians do not use antiepileptics, majority treat with OXC or CBZ. Outcome is good; seizures are easily controlled especially in cases with secondary generalization; remission occurs at 18 yrs in most cases.
  2. Juvenile Absence Epilepsy (JAE):The onset is generally during or after puberty. The frequency of absences is less than in CAE. Treatment is similar to CAE. The incidence of GTCS and the likelihood of absence persisting into adulthood are higher than in CAE.
  3. Juvenile Myoclonic Epilepsy (JME): This puberty 12-18 yrs; boys are equals to girls. It is characterized by the occurrence of myoclonic jerks, shortly after awakening with no loss of consciousness. The seizures are precipitated by sleep deprivation and hand activities. About 90% cases also have GTCs on awakening. About 30% cases have absences. The interictal EEG shows bilateral symmetric diffuse spike waves and poly-spike waves 4-6 Hz with photosensitivity.
    Treatment: Valproate is the drug of choice. Lamotrigine has been found effective and may be preferred in some adolescent girls. Precipitating factors such as sleep deprivation, early awakening, flickering lights and fatigue should be avoided. The epilepsy gets well controlled, but long term AEDs are required to avoid recurrence.
  4. Progressive myoclonic epilepsy (PME): This is characterized by development of progressive myoclonus, ataxia and other neurological signs. Myoclonic seizures are generalized, and often associated with other seizure types. There is progressive mental deterioration. The underlying etiology is variable and conditions such as Unverricht-Lundborg disease, Lafora body disease and Neuronal ceroid lipofuscinosis need to be considered. Valproate and BDZs especially CZP are generally tried. Treatment is difficult, polytherapy is often required.

Onset at any Age: Certain Localization related epilepsies may occur at any age. These include Mesial temporal lobe epilepsy syndromes, Lateral temporal lobe syndromes, Frontal lobe epilepsy syndromes, Parietal lobe epilepsy syndromes, Occipital lobe epilepsy syndromes. They are characterized by predominantly partial seizures which may be simple or complex, and at times tonic clonic seizures. The associated symptomatology is determined by the localization. The EEG shows a localized seizure focus. OXC & CBZ are the drugs of choice for most partial seizures.

Certain Localization related epilepsies may occur at any age. These include Mesial temporal lobe epilepsy syndromes, Lateral temporal lobe syndromes, Frontal lobe epilepsy syndromes, Parietal lobe epilepsy syndromes, Occipital lobe epilepsy syndromes.
B. Recurrent seizures secondary to CNS Infections
Seizures are often a presenting feature of most CNS infections. They are generally acute symptomatic and short lived. However, in some cases, infections may leave permanent defects, such as infarcts, gliosis etc that maybe responsible for long term, recurrent seizures. Both pyogenic and tubercular meningitis, and severe meningoencephalitis may cause symptomatic epilepsy. The nature of the seizures is determined by the type of CNS involvement. The AEDs are chosen according to the type of seizures Table 5.
Table 5. Drug choices by seizure type
Seizure type First-line Second-line Others
Tonic LTG, VAL CLB, CLZ,
LEV, TOP
AZL, PB,
PHT, PRM
Atonic LTG, VAL CLB, CLZ,
LEV, TOP
AZL, PB,
PRM
Focal
with/without secondary generalization
CBZ,
LTG,
OXC,
VAL, TOP
CLB, GBP
LEV, PHT,
TGB
AZL, CLZ,
PB, PRM


CNS granulomas, particularly NCC is the commonest cause of partial seizures in India. The NCC lesions are usually solitary and the seizures are often brief, seen in clusters in an otherwise normal child. Neuroimaging is thus indicated in all cases of partial seizures (that are not clearly due to an idiopathic epilepsy syndrome such as BCECT) in our country. The drugs of choice are OXC & CBZ. The seizures are usually well controlled.
Conclusion

Management of recurrent seizures

requires understanding of the type of seizures, and whenever possible the CES. A good EEG is needed in all cases. Further investigations can be accordingly planned and the etiology arrived at, in most cases. Appropriate AEDs and other therapies can then be decided. Seizures that are refractory to AEDs may require alternative therapies and surgery. Management of associated problems and co-morbidities is also important. Patient rapport, patient and parent education are important to ensure compliance and regular follow up.

Abbreviations Used
Antiepileptic Drugs (AED), Carbamazepine (CBZ), Phenytoin (PHT), Valproate (VAL), Phenobarbitone (PB), Oxcarbamazepine )OXC), Lamotrigine (LTG), Topiramate (TPM), Gabapentin (GBP), Ethosuximide (ESM), Zonisamide (ZM), Adrenocorticotropic hormone (ACTH).
References :
  1. Commission on Classification and Terminology of the International League Against Epilepsy. Proposal for revised clinical and electroencephalographic classification of epileptic seizures. Epilepsia. 1981;22:489-501.h
  2. Commission on Classification and Terminology of the International League Against Epilepsy. Proposal for revised classification of epilepsies and epileptic syndromes. Epilepsia 1989;30:389-99.
  3. Glauser T, Ben- Menachem E, Bourgeois B, et al. ILAE treatment guidelines: Evidence-based analysis of Antiepileptic drug efficacy and effectiveness as initial monotherapy for epileptic seizures and syndromes. Epilepsia, 2006;47:1094-120.
  4. Wheless JW, Clarke DF, Carpenter D. Treatment of pediatric epilepsy: expert opinion, 2005. J Child Neurol, 2005; Suppl. 1:S1-60.
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