EPILEPSY WEEK PREREADING

Talley & O’Connor p400-402 Causes of unconsciousness =

C.O.M.A. CO2 narcosis (uncommon) Overdose Metabolic/endocrine Apoplexy (Stroke or other CNS insult)

General inspection DRABC Posture (neck extension, decerebrate,

decorticate) Involuntary movements

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

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

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)

Harrison’s chap 363

Partial seizure – discrete CNS focus Simple – fully conscious

Motor, sensory, autonomic, or psychic symptoms

May progress (eg Jacksonian 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

Harrison’s chap 363Generalized 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

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

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

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

Harrison’s chap 363Antiepileptic 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: Valproic acid, gabapentin, tiagabine

Modulate release of synaptic vesicles: Levetiracetam

(Probably) Inhibit T-type Ca2+ channels in thalamic neurons: Ethosuximide and valproic acid

Harrison’s chap 363Approach to seizure management

Harrison’s chap 363Approach to seizure management

Harrison’s chap 363DDx 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, nonepileptic myoclonus, paroxysmal choreoathetosis Special considerations in children

Breath-holding, apnea, night terrors, migraine, benign paroxysmal vertigo

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

Harrison’s chap 363

Treatment of seizures and epilepsy Surgery

focal neocortical resection anteromedial temporal lobe resection Amygdalohippocampectomy Lesionectomy multiple subpial transection Multilobar resection Hemispherectomy Corpus callosotomy

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

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)

Harrison’s chap 363

Ongoing epilepsy management Interictal behavior

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

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