Epilepsy week prereading

1. Epilepsy week prereading

2. Talley & O’Connor p400-402 • Causes of unconsciousness = C.O.M.A. • CO2narcosis (uncommon) • Overdose • Metabolic/endocrine • Apoplexy (Stroke or other CNS insult) • General inspection • DRABC • Posture (neck extension, decerebrate, decorticate) • Involuntary movements

3. Talley & O’Connor p400-402 • Level of consciousness • GCS • Coma, stupor, drowsy, alert • AVPU:Alert, Voice response, Pain response, Unresponsive • Neck • Trauma, stiffness, Kernig’s sign • Head • Inspect, palpate, Battle’s sign

4. Talley & O’Connor p400-402 • Face • General • Asymmetry, jaundice, myxoedema • Eyes • Pupils, fundus, haemorrhage, position, movement • Ears and nostrils • Blood and CSF • Mouth and tongue • Trauma, corrosion, gum hyperplasia, breath odor

5. Talley & O’Connor p400-402 • Limbs • Trauma, needle marks, tone, reflexes, pain response • Trunk • Trauma, heart, lungs, abdomen • Other • Urine • Blood sugar • Body temp • Stomach contents (if indicated)

6. Harrison’s chap 363 Partial seizure – discrete CNS focus • Simple – fully conscious • Motor, sensory, autonomic, or psychic symptoms • May progress (egJacksonian march) • May proceed to complex partial seizure • May proceed to general seizure • Complex – impaired consciousness • Preceded by aura (simple partial seizure) • Automatisms – unconscious behaviour • Postictal confusion, anterograde amnesia

7. Harrison’s chap 363 Generalized seizure – affects both hemispheres • Absence seizure (petit mal) • Brief lapse of awareness • Subtle motor signs (eg blinking) • No post-ictal confusion • Tonic-clonic seizure (grand mal) • 10-20s general muscle contraction (tonic) • Periods of relaxation (clonic) • Post ictal flaccidity and unresponsiveness, then impaired consciousness, confusion, headache, fatigue • Atonic seizure • Brief loss of postural control and impaired consciousness • No post-ictal confusion • Myoclonic seizure • Sudden, brief muscle contraction • Focal or generalized • Eg jerk while falling asleep

8. Harrison’s chap 363 Epilepsy syndromes (disorders featuring epilepsy) • Juvenile myoclonic epilepsy • Responds well to anticonvulsants • Lennox-Gastaut syndrome • Underlying CNS disease, poor prognosis • Mesial temporal lobe epilepsy syndrome • Refractory to anticonvulsants • Responds well to surgery • Other examples with known genetic basis

9. Harrison’s chap 363 Causes of seizures • Neonates • Perinatal hypoxia, infection, drug withdrawal, trauma, metabolic, genetic, developmental • Children • Febrile, trauma, developmental, infection, genetic, idiopathic • Adolescents • Trauma, drugs, brain tumour, infection, genetic, idiopathic • Young adults • Trauma, drugs, brain tumour, alcohol withdrawal, idiopathic • Older adults • Trauma, CVA, brain tumour, alcohol withdrawal, metabolic disorder, degenerative CNS, idiopathic

10. Harrison’s chap 363 Mechanisms of seizures • Initiation and propagation • high-frequency action potentials bursts • Hypersynchronization • Interstitial and synaptic funkiness with electrolytes and neurotransmitters • Funkiness spreads to surrounding areas • Epileptogenesis • Normal neural network becomes hyperexcitable • Injury? Development? • Genetic • Ion channelopathies

11. Harrison’s chap 363 Antiepileptic drugs block initiation or propogation • Inhibit Na+-dependent action potentials: • phenytoin, carbamazepine, lamotrigine, topiramate, zonisamide • Inhibit voltage-gated Ca2+channels: • Phenytoin • Decrease glutamate release: • Lamotrigine • Potentiate GABA receptor function: • benzodiazepines and barbiturates • Increase GABA availability: • Valproicacid, gabapentin, tiagabine • Modulate release of synaptic vesicles: • Levetiracetam • (Probably) Inhibit T-type Ca2+ channels in thalamic neurons: • Ethosuximideand valproicacid

12. Harrison’s chap 363 Approach to seizure management

13. Harrison’s chap 363 Approach to seizure management

14. Harrison’s chap 363 DDx of seizures • Syncope • Vasovagal, arrythmia, hypotension, cardiac failure • Psychological • Panic attack, psychogenic seizure, hyperventilation • Metabolic • Hypoglycemia, hypoxia, alcoholic blackout, DTs, psychoactive drugs • Migraine • TIA • Sleep disorders • Narcolepsy, cataplexy, benign sleep myoclonus • Movement disorders • Tic, nonepilepticmyoclonus, paroxysmal choreoathetosis • Special considerations in children • Breath-holding, apnea, night terrors, migraine, benign paroxysmal vertigo

15. Harrison’s chap 363 Treatment of seizures and epilepsy • Treat underlying condition • Avoid precipitating factors • Antiepileptic drugs • Big table of doses and adverse effects • Some patients can eventually cease drug therapy

16. Harrison’s chap 363 Treatment of seizures and epilepsy • Surgery • focal neocortical resection • anteromedialtemporal lobe resection • Amygdalohippocampectomy • Lesionectomy • multiple subpialtransection • Multilobar resection • Hemispherectomy • Corpus callosotomy

17. Harrison’s chap 363 Status epilepticus • Continuous seizures • Repetitive seizures with impaired consciousness between • GCSE = generalized convulsive status epilepticus • GCSE > 5min is an emergency: • cardiorespiratory dysfunction, hyperthermia, metabolic derangement, irreversible CNS injury • EEG may be required to show seizure activity after 30-45 minutes

18. Harrison’s chap 363 GCSE management • ABC and hyperthermia • IV access, lab tests for metabolic abnormalities • Anticonvulsants • Begin with Lorazepam • Valproate? • Phenytoin or Fosphenytoin • Admit to ICU if seizures continue • General anesthesia (propofol, midazolam, pentobarbital)

19. Harrison’s chap 363 Ongoing epilepsy management • Interictalbehavior • Depression, memory deterioration, postictal psychosis or anxiety • Psychosocial issues • Cultural stigma, fears of death and mental retardation • Employment, driving, other activities • Legislation varies • Mortality • Underlying disease, Accidents, GCSE, SUDEP – Sudden unexpected death in epileptic patients

20. Harrison’s chap 363 Special issues for women with epilepsy • Catamenial epilepsy • Association of seizures with menstruation • Pregnancy • Seizure frequency may increase or decrease • Teratogenic effect of antiepileptic drugs • Contraceptive pill • Interactions with medication • Breastfeeding • Drugs are expressed in breast milk, but no evidence of long term harm to infants