Childhood Epilepsy Syndromes

• The following information pertains to childhood epilepsy syndromes

Classification of Childhood Epilepsy Syndromes

• Classifications according to the International League Against Epilepsy (ILAE).

Idiopathic

• Age-related onset
• Includes conditions like:
  • Benign childhood epilepsy with centro temporal spikes.
  • Childhood epilepsy with occipital paroxysms.
  • Primary reading epilepsy.

Symptomatic

• Chronic progressive epilepsia partialis continua
• Syndromes presentation with specific seizure modes.

Cryptogenic

• Presumed to be symptomatic, but the etiology is unknown.

Classification of Generalized Epilepsies and Syndromes

Idiopathic

• Defined as age-related onset
• Benign neonatal familial convulsions
• Benign neonatal convulsions
• Benign myoclonic epilepsy of infancy
• Childhood absence epilepsy
• Juvenile absence epilepsy
• Generalized epilepsy with tonic-clonic seizures
• Epilepsy with seizures precipitated by specific activation modes (reflex epilepsy)

Cryptogenic

• Organized by age of onset:
  • West syndrome
  • Lennox-Gastaut syndrome
  • Epilepsy with myoclonic-astatic seizures (Doose syndrome)
  • Epilepsy with myoclonic absence seizures

Symptomatic

• Early myoclonic encephalopathy
• Early infantile epileptic encephalopathy with burst suppression
• Cerebral malformations with focal or generalized epilepsy
• Inborn errors of metabolism, presenting with progressive myoclonic epilepsy

Undetermined

• Severe myoclonic epilepsy of infancy (Dravet syndrome)
• Acquired epileptic aphasia (Landau-Klifner syndrome)

Focal Epilepsy

Idiopathic

• Benign infantile myoclonic epilepsy (non-familial)
• Benign childhood epilepsy with centro temporal spikes
• Early-onset benign childhood occipital epilepsy (Panayiotopoulos syndrome)
• Late-onset childhood occipital epilepsy (Gastaut type)

Familial

• Autosomal dominant
  • Benign familial neonatal seizures
  • Benign familial infantile seizures
  • Autosomal dominant nocturnal frontal lobe epilepsy
  • Familial temporal lobe epilepsy

Symptomatic

• Limbic system epilepsy

Benign Idiopathic Neonatal Convulsions (5th Day Fits)

• This condition is rare
• Prevalence is less than 1% of childhood epilepsy cases
• Onset occurs between days 1-7 of life, mostly around day 5
• Seizure types include partial clonic or subtle manifestations like apnea.
• EEG patterns show asynchronous Rolandic theta rhythm during interictal periods.
• EEG patterns show rhythmic spikes and slow waves during ictal periods
• The etiology is idiopathic
• Treatment may include phenobarbitone, phenytoin, or benzodiazepines.
• Treatment may not be necessary if seizures are infrequent
• Prognosis is excellent with treatment, seizures usually do not reoccur
• Autosomal dominant inheritance is common
• Possibly due to a disorder in potassium channels

Early Myoclonic Encephalopathy (Neonatal Myoclonic Encephalopathy)

• Prevalence is <1% of childhood epilepsy cases
• Onset during the neonatal period.
• Seizure types include segmental myoclonia, generalized myoclonia, and partial motor seizures.
• Seizures evolve into infantile spasms after several months
• EEG shows bursts of spikes, fluctuating sharp and slow waves (burst suppression), later changing to hypsarrhythmia.
• Etiology is related to metabolic disorders.
• Treatments corticosteroids, benzodiazepines, and vigabatrine are not typically effective
• Prognosis is poor
• Most infants are neurologically abnormal, and 50% die within a year.

West Syndrome (Infantile Spasms and Hypsarrhythmia)

• Uncommon disorder
• Accounts for 1-5% of all childhood epilepsy cases.
• Onset typically occurs between 3-13 months, peaking at 5-9 months.
• Seizures are brief tonic or clonic spasms
• Seizures occur frequently in clusters throughout the day
• Spasms involve flexor-extensors (neck and arms flex, legs extend) or flexor (jack-knife, salaam attacks) or extensors.
• Sometimes only head nods are seen in children
• EEG shows chaotic, large amplitude slow waves and spikes, with sharp waves varying in site and size.
• EEG shows hypsarrhythmia during drowsy or light sleep
• Atypical patterns can include burst suppression and preserved basal rhythm.
• 70-80% are symptomatic, linked to hypoxic-ischemic encephalopathy, tuberous sclerosis, postnatal infection, or metabolic disorders
• 20-30% are idiopathic/cryptogenic), possibly due to cortical dysplasia
• Treatment includes vigabatrine (especially for tuberous sclerosis), steroids (ACTH or prednisolone), valproate, nitrazepam, lamotrigine, topiramate, pyridoxine, and IVIG.
• Poor prognosis
• Can lead to severe developmental delay (70%) with only 5-10% achieving normal results.

Severe Myoclonic Epilepsy of Infancy (Dravet Syndrome)

• Rare disease
• <1% of all childhood epilepsy cases.
• Onset occurs between 3-8 months
• Seizures include febrile seizures that are frequently prolonged and occur often in the first year of life.
• Between 15-24 months, frequent generalized or segmental myoclonic seizures begin.
• 50% of patients have atypical absence and/or focal motor seizures, with or without generalization.
• EEG shows fast spikes and polyspikes during ictal periods, with generalized or focal abnormalities and photosensitivity during interictal periods.
• Valproate, benzodiazepines, topiramate, and stiripentol are used for treatment
• Carbamazepine and lamotrigine can exacerbate seizures
• Poor prognosis
• Characterized by refractory epilepsy and developmental delays, especially in speech and language.

Absence Epilepsy (Previously Petitmal Epilepsy)

• Relatively common
• Accounts for 5-12% of all childhood epilepsy cases
• Onset occurs between 3-12 years, peaking at 6-7 years.
• Seizures display a prompt onset/cessation of impaired consciousness, lasting 5-15 seconds and recurring 10-100 times daily.
• Seizures are often accompanied by eyelid fluttering, automatisms (lip smacking, chewing), and hand fidgeting. EEG shows paroxysmal single or brief generalized spike-wave discharges during hyperventilation for 3 minutes
• EEG shows 3-3.5 Hz spike-wave patterns during ictal periods.
• Etiology is idiopathic, mainly genetic.
• Neuroimaging not needed
• Treatment: ethosuximide, valproate, and lamotrigine, either alone or in combination.

Generalized Tonic-Clonic Epilepsy (Grandmal Epilepsy)

• Comprises 1-5% of all childhood epilepsy cases
• Onset occurs between 6-20 years, peaking at 11-15 years.
• Seizures are generalized tonic-clonic type and usually occur after waking from sleep or during relaxation.
• Child initially loses consciousness for a few seconds
• Child gets tonic spasms with respiratory distress and cyanosis and followed by clonic movements of the limbs and trunk.
• Child enters deep sleep for minutes
• Child stops seizing with drowsiness that can last longer
• Potential complications: tongue biting, defecation, or urination during attacks
• Etiology is idiopathic and presumed to be genetic
• Neuroimaging is rarely needed
• Treatment includes valproate, carbamazepine, lamotrigine, and levetiracetam.
• Good prognosis
• May respond well to antiepileptic drugs (AEDs), but relapses are common. The relapse rate is 50-70%
• Variant of complex focal epilepsy that begins in childhood and is outgrown in adolescence
• Prevalence is up to 10% of all epilepsies in children between the ages of 4 and 10.
• Family history is positive in 13% of cases
• Autosomal dominant presentation may be present in 21 out of 100,000 children.
• Attacks most commonly related to sleep
• Attacks may cause gargling during sleep or when the patient is in sleep or awake/semiconscious
• Involves the face, pharynx, and possibly the arm
• Patient is unable to speak and may drool saliva with tonic or clonic contraction on one side of the face.
• Can be combined with focal and other focal complex epilepsies
• May not need treatment
• EEG during sleep shows abnormal Centro temporal spikes and waves in one or both pre-Rolandic areas
• Also called Benign Epilepsy with CentroTemporal Spikes (BECTS)
• Treatment includes carbamazepine or phenytoin

Juvenile Myoclonic Epilepsy (JME)

• Etiology is presumed to be genetically determined.
• Onset occurs between 12-18 years.
• Seizures are characterized by myoclonic jerks
• Jerks last less than 1 second and may or may not produce a loss of awareness
• Jerks can happen multiple times a day, especially in the morning or with strong lights.
• Sudden jerks, clumsiness, or jitteriness, should be questioned, especially occurrences in the morning

Generalized tonic-clonic seizures occur

• Starts repetitive myoclonic seizures that culminate in a generalized bilateral convulsion.
• Seizures are typically self-limited and infrequent
• Nearly all JME patients have at least one. This is often the first seizure recognized

Myoclonic-atonic seizures, also known as Doose Syndrome, present as

• Staring
• Behavioral arrest
• Falling or head drops

Interictal EEG

• Generalized 4-6 Hz atypical spike and polyspike and wave discharges
• Photo-paroxysmal responses precipitate myoclonic seizures in 30-90%
• Imaging is normal
• Responsiveness to AED treatment - 80-90%
• Traditional treatment is Valproic acid
• Side effects may limit its use, especially in women of reproductive age
• Other broad-spectrum AEDs are used
• Carbamazepine, oxcarbazepine, and phenytoin can exacerbate seizures
• Spontaneous remission is rare; treatment lasts forever
• Comorbidities include normal cognition
• Executive dysfunction is common

Acute Post-Infectious Cerebellitis

• Commonly occurs after infections such as varicella, enterovirus, EBV, mumps, and measles.
• Usually post-infectious
• Immune-mediated inflammatory process
• Occurs in young children aged 2-7 years old.
• Presents with abrupt onset of ataxia and behavioral disorder after about 5-14 days
• Happens after rash disappearance
• May occur in a pre-eruptive stage.
• Severe symptoms last 1-2 weeks, which eventually improves after 4-8 weeks
• Full recovery without lasting effects
• Indicated neuroimaging in atypical cases
• Differential diagnosis: Miller-Fisher syndrome
• Treatment: supportive and sometimes corticosteroids
• Administration of antivirals rarely occurs

Acute Disseminated Encephalomyelitis (ADEM)

• More common in females aged 6-9 years.
• Usually 2 weeks after viral infections or life-attenuated vaccines.
• Presents with behavioral changes and encephalopathy, combined with spinal cord signs.
• Occurs w/in 2 weeks after viral infections
• Immune driven symptoms and signs
• Both the brain and spinal cord have concurrent symptoms
• Can be triggered by the same condition or follow one another
• Majority shows a monophasic course
• 10% are polyphasic
• Manifests usually within approximately 3 months- bilateral optic neuritis, similar to multiple sclerosis (MS)
• Oligo clonal band is negative in the cerebral spinal fluid (CSF)
• MRI of both the brain and spinal cord shows demyelination.
• Treatment involves pulsed steroids followed by a tapering dose over time with supportive treatments, e.g., anticonvulsants and physiotherapy.

Conclusion

• Recognizing epilepsy in children is significant for improving their quality of life and preventing associated events and complications.
• Drug treatment plays a crucial role in controlling this severe condition.
• Acute cerebellar ataxia and ADEM are the most common post-infectious inflammatory diseases of the central nervous system (CNS) in children.