Epilepsy

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  • Created by: z
  • Created on: 04-03-16 18:59

Epilepsy

  • Chronic disorder characterised by recurrent seizures
  • May vary from brief lapse in attention or muscle jerks to severe and prolonged convulsions
  • Seizure: clinical phenomenon due to abnormal, synchronous, cortical discharges
  • Working definition of epilepsy: two or more seizures w/o clear symptomatic provocation
  • 400,000 people in UK
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Differential of sudden collapse

Vasovagal syncope

Seizure

Cardia syncope

Cataplexy

Hypoglycaemic attack 

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Vasovagal syncope

  • Syncope= sudden impairment of consciousness and loss of tone
  • Due to reduced blood/O2 to brain
  • Often a provoking factor- clood, pain, deghyr=dration etc
  • Presyncopal symptoms
    • Light-headness, warmth, dizziness building in intensity, possible loss of vision/hearing
  • Stiffening and jerking common
  • Urinary and faecal incontinence may occur
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Cardiac syncope

  • Sudden LOC w/ brief/no warning and rapid recovery
  • Cardiac Hx
  • FHx of sudden death
  • Thus, all pt w/ transient LOC should have ECG
  • ECG “clues”
    • Long QT interbal
    • Prior MI
    • Anterior (V1-3) T inversion
    • QRS duration in V1-3/V4-6 > 1.2 = RV dysplasia
    • Ectopy
    • Bradycardia
    • AV delay/block
    • Bifascicular block
    • Ventricular hypertrophy
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Cataplexy

  • No LOC
  • Provoked by emotion
  • Nearly always in context of narcolepsy
  • Assoc freq dreams, sleep paralysis
  • Dx- sleep latency test- rapid falling asleep + rapid onset of REM
  • CSF shows decr/absent hypocretin
    • = neuropeptide that regulates arousal, wakefulness, and appetite
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Seizure classification

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Seizure investigation

  • collateral history important
  • if suspect syncopal:
    • ECG
  • if suspect seizure
    • MRI
      • good for subtle abnormalities e.g. hippocampal sclerosis > temporal lobe epilepsy
    • EEG (maybe)
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Whether to treat seizures

  • UK- start therapy after 2 spontaneous seizures as high risk of further seizure
  • Start after 1 tonic-clonic if Hx of partial, absence or myoclonics or if risk to safety if another seizure occurs e.g. if need to drive
  • Do not start if very infrequent tonic-clonic, simple/complex partial seizures, woman of child bearing age (teratogenicity)
  • NB- DVLA to drive need:
  • Single seizure w/ imaging and EEG unsupportive of epilepsy – 6 months
  • Epilepsy – 12 months seizure free
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Mechanisms of Tx + seizure type treated

  • Barbiturates – incr GABA – partial
  • Benzodiazepines – incr GABA – status
  • Carbamazepine – inhib Na channels – TC
  • Phenytoin – inhib Na and Ca channels – status
  • Valproate – incr GABA and inhib NA channels – partial, TC, absence
  • Levetiracetam – inhib synaptic conduction – partial
  • Lamortrigine – inhib Na channels – partial, TC
  • Topiramate – prob decr glutamate (NK) 
    • Lev, lam and top are new- more ££, not more effective, improved s/e, interaction, tolerability, some a/e found after years of use
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