Epilepsies of childhood

Epilepsies of childhood

1. epidemiology

   • incidence= 0.5%
     • but commoner after the 1st year of life
   • prevalence= 0.5%

2. chronic neurological disorder

   • recurrent unprovoked seizures
     • transient signs & sx
       • assoc w/ abnormal, excessive or synchronous neuronal activity

3. international classification of epilepsy

   • generalised
     • discharge arises from both hemispheres
       • bilat synchronous seizure discharge on EEG or varying asymmetry
     • absence
       • transient loss of consciousness
         • w/ an abrupt onset & termination
         • w/ some flickering of eyelids & minor alteration in mm tone
       • typical (petit mal)
       • atypical
       • precipitating factors
         • hyperventilation
     • myoclonic
       • brief, often repetitive, jerking movements
         • limbs
         • neck
         • trunk
       • non-epileptic movements
         • seen physiologically in hiccoughs
     • tonic-clonic
       • rhythmic contraction of mm groups ff the tonic phase
       • in rigid tonic phase (1)
         • fall to ground
           • injury
         • don't breathe
           • become cyanosed
       • clonic phase (2)
         • limb jerking
         • irregular breathing
         • cyanosis persists
         • saliva may build up in mouth
         • tongue biting
         • urinary incontinence
         • duration: few seconds to mins
           • fb unconsciousness or deep sleep for several hours
     • atonic
       • often combined w/ a myoclonic jerk
         • fb transient loss of muscle tone
           • -> sudden fall to the floor or drop of the head
     • no warning
     • symmetrical seizure
     • tonic
       • generalised increase in tone
   • focal
     • where seizures arise from 1 or part of 1 hemisphere
       • manifestations depend on part of the brain where discharge originates
         • frontal lobe seizures
           • involve motor or premotor cortex
             • motor phenomena
           • may -> clonic movements
             • may travel proximally (Jacksonian march)
           • asymmetrical tonic seizures can be seen
             • hyperkinetic
             • can be mistaken for non-epileptic events
           • atonic seizures
             • may arise from mesial frontal discharge
         • temporal lobe seizures
           • commonest of all epilepsies
           • may result in strange warning feelings
             • or aura w/
               • smell
               • taste abnormalities
               • sound & shape distortions
           • ff spread to pre-motor cortex
             • automatisms
               • lip-smacking
               • plucking @ one's clothing
               • walking around in a non-purposeful manner
           • deja-vu
             • intense feeling of having been in same situation before
           • jamais-vu
             • never having been in a situation before
           • impaired consciousness
           • length of event longer than a typical absence
         • occipital seizures
           • cause distortion of vision
         • parietal lobe seizures
           • cause contralat dysaesthesias (altered sensation)
           • distorted body
     • consciousness may be retained or lost
     • seizure may be followed by generalised tonic-clonic seizure
   • can be unclear esp in < 5 years

4. diagnosis

   • based on hx
     • child
     • eye witnesses
     • triggers
     • impairments
       • educational
       • psychological
       • social
   • video
   • examination
     • skin markers
       • neurocutaneous syn
       • neurological abnormalities
   • epilepsy usually has idiopathic cause
     • but may be presentation or complication
       • of an underlying neurological disorder

5. Ix

   • EEG
     • indication
       • whenever epilepsy suspected
     • interpreted to ID a background that is abnormal for child's age
       • asymmetry or slowing
         • underlying structural abnormalities
       • evidence of neuronal hyperexcitability
         • sharp waves
         • spike-waves complexes
     • unless seizure is captured
       • only adds supportive evidence or not for the diag
     • many kids w/ have a normal initial EEG
       • and vice versa
     • if standard EEG is normal
       • sleep or sleep-deprived record can help
     • 24h ambulatory EEG
     • video-telemetry
     • subdural electrodes
       • for assessment prior to surgery
   • structural imaging
     • e.g. MRI & CT scans
     • not routinely required for childhood generalised epilepsies
     • indications
       • neurological signs btw seizures
       • focal seizures
       • those indicated to ID tumour, vascular lesion or area of sclerosis
     • MRI FLAIR
       • better detect mesial temporal sclerosis in temporal lobe epilepsy
   • functional imaging
     • to detect abnormal hypometabolism
       • suggestive of seizure foci
     • PET
     • SPECT
     • can use alongside
       • psychological testing
         • including memory assessment
         • minimise risk of postop impairment
   • metabolic ix
     • indications
       • developmental regression
       • seizures related to feeds or fasting
   • genetic studies
     • due to genetic deletions
       • causing abnormalities of Na+ & other ion chanels
         • e.g. SCN1A mutations in severe myoclonic epilepsy of infancy

6. Mx

   • explanation and advice
     • to help adjustment to the condition
       • psychological help
     • those w/ photosensivity
       • sit at a distance from TV
   • specialist epilepsy nurse
     • education & advice
       • lifestyle issues
         • adolescents
           • driving
             • only after 1 year free of seizures
           • contraception
           • pregnancy
           • adherence
           • seizure precipitants
             • alcohol
             • poor sleep routines
   • Rx
     • decision to treat
       • based on level of inconvenience seizures bring
       • DON'T institute after single unprovoked seizure
     • Anti-epileptic drug (AED)
       • not all seizures require AED
         • base this decision on
           • seizure type
           • frequency
           • social & educational conseq
           • possible s/e of drugs
       • choose the approp drug for the seizure
         • inapprop AEDs may be detrimental
           • carbamazepine can worsen absence & myoclonic seizures
       • monotherapy at minimum dosage is desired
       • drug levels not measured routinely
       • kids w/ prolonged seizures are given rescue therapy
         • e.g. rectal diazepam & buccal midalzolam
       • therapy can usually be discontinued after 2 years free of seizures
     • tonic-clonic
       • 2nd line
         • lamotrigine, topiramate
       • 1st line
         • valproate, carbamazepine
     • absence
       • 1st line
         • valproate, ethosuximide
       • 2nd line
         • lamotrigine
     • myoclonic
       • 1st line
         • valproate
       • 2nd line
         • lamotrigine
     • focal
       • 1st line
         • carbamazepine, valproate
         • lamotrigine
           • most effective
             • slow titration
       • 2nd line
         • topiramate, levetiracetam, oxacarbazepine, gabapentin, tiagabine, vigabatrin
     • ketogenic (fat-based) diets
       • helpful in some kids
       • mechanism of action poorly understood
     • vagal nerve stimulation
       • delivered using externally programmable stimulation
         • wire around vagal nerve
           • on trial
     • surgery
       • well localised seizures
         • demonstrated by good concordance btw EEG, MRI & functional imaging findings
       • temporal lobectomy
         • for mesial temporal sclerosis
       • hemispherotomy or hemispherotomy
         • isolation of hemisphere which isn't removed so as avoid post-op in space
   • promote independence & confidence
   • informing the school
     • vigilance for absence episodes
     • avoiding deep baths, not swimming alone in deep water