Epilepsy Flashcards
Define seizure (3)
A sudden irregular discharge of electrical activity in the brain causing a sensory disturbance, unconsciousness or convulsions.
Define convulsion. (2)
Uncontrolled, shaking movements due to rapid muscle contraction and relaxation.
Define aura. (2)
A perceptual disturbance experienced prior to a neurological event eg seizure, migraine.
Define epilepsy. (3)
A neurological disorder characterised by recurrent episodes of LoC, sensory disturbance, or convulsions associated with abnormal electrical activity.
Define status epilepticus. (3)
Epileptic seizures occurring continuously without the regain of consciousness in between. A medical emergency as it can remove the patients ability to breathe.
Describe the two main types of seizures. (2)
Partial - involving a focal portion of the brain.
Generalised - involving diffuse areas of the brain.
Describe the types of partial seizure. (2)
Simple - consciousness maintained
Complex - consciousness impaired.
Describe the two most common types of partial seizure. (7)
Temporal lobe is most common, often following brain injury, often presents before 20 years, and is commonly seen with clothes plucking and lips smacking.
Frontal lobe is the next common, presenting its abnormal motor signs on the contralateral side to the seizure.
Describe the types of generalised seizure. (10)
Atonic - sudden loss of tone - “drop attack”
Tonic - sudden increase in tone
Myoclonic - shock like muscle jerks (no increase in tone)
Tonic-clonic - 1st tonic (increase tone) then clonic (convulsions)
Abscence - “daydreaming”
Describe the investigation you would perform on a patient presenting with seizures. (4)
EEG
MRI
ECG
Bloods
Describe the questions you would ask when taking a history about the time immediately prior to the seizures. (9)
PMH - trauma, brain disease FH - epilepsy Triggers - strobe lighting Aura - sights, smells First signs or symtoms
Describe the questions you would ask when taking a history about the seizure itself. Who old you need to get this history from? (7)
Description - tone, movements Duration Self resolving Abrupt or gradual end Needs a collateral history
Describe the questions you would ask when taking a history about the time directly after the seizure. (4)
Post-ictal state - groggy?
Tongue biting
Incontinence
Neurological deficits - stroke?
Describe causes of secondary epilepsy. (13)
Vascular - stroke, TIA Infection - meningitis, abscess Trauma - intercerebral haemorrhage Autoimmune - SLE Metabolic - hypoxia, hypoglycaemia, hyponatraemia, thyroid dysfunction. Iatrogenic - drugs, alcohol withdrawal Neoplastic - intercerebral mass.
Explain the purpose of performing an EEG, and how it would help. (3)
Explain what you would do if the history indicated epilepsy but the initial EEG was inconclusive. (3)
An EEG is taken to support a clinical history suggestive of epilepsy. Light stimulation and hyperventilation are employed to induce a seizure.
Can’t do with risk of syncope (false positive).
Consider repeated EEGs, sleep EEGs, ambulatory EEGs.
Explain the mechanism of action of sodium channel blockers for treating epilepsy. (2)
Give 5 examples of sodium channel blockers. (5)
Caused Na+ channels to remain in an inactive state to prevent action potentials from firing repeatedly.
Carbamazepine, lamotrigine, sodium valproate, phenytoin, topiramate.
Explain the mechanism of action of calcium channel blockers for treating epilepsy. (3)
Give 2 examples of calcium channel blockers. (2)
Prevents activity of calcium channels to prevent the depolarisation that causes the classic waveform patterns seen in abscence seizures.
Ethosuximide, sodium valproate.
Explain the mechanism of action of GABA potentiators in treating epilepsy. (1)
Give 2 examples of GABA potentiators. (2)
Enhance the inhibitory effects of GABA at the synapse.
Barbiturates, benzodiazepines.
Explain the mechanism of action of GABA transaminase inhibitors in treating epilepsy. (2)
Give 1 example of a GABA transaminase inhibitor. (1)
Prevent the breakdown of GABA to increase its inhibitory action at synapses.
Vigabatrin
Explain the mechanism of action of Gabapentin. (2)
Increases GABA production so increases the inhibitory effect at synapses.
Explain the mechanism of action of Levetiracetam. (3)
Binds to synaptic vesicles to inhibit the release of neurotransmitters even if there is calcium channel action. Inhibitory on the synaptic transmission.
Describe 4 side effects of all antiepileptics.
Dizziness
Fatigue
Diplopia
Ataxia
Describe 2 side effects of Gabapentin.
Irritability and behaviour change
Weight gain.
Describe 3 side effects of Topiramate.
Weight loss
Metabolic acidosis
Language dysfunction
