Epilepsy Flashcards
The cause of epilepsy is unknown in up to how much of the population?
2/3rds
Pathophysiology of epilepsy
Imbalance between inhibitory and excitatory signals in the brain leading to synchronous hyperexcitable activity within neurons
Risk factors for epilepsy
Cerebrovascular disease
Head trauma
Cerebral infections
Family hx of epilepsy or neurological illness
Premature birth
Congenital malformations of the brain
Genetic conditions associated with epilepsy
In terms of seizure classification, what is a focal and generalised seizure?
Focal: localised to a network of neurons in one hemisphere of the brain and often seen with underlying structural disease
Generalised: affects both hemispheres of the brain and is associated with neuronal networks
Describe absent, tonic-clonic, myoclonic and atonic seizures
Absent seizures: brief pauses (<10s), suddenly stops talking mid sentence and carries on where left off
Tonic-clonic: LOC, limbs stiffen (tonic), jerk (clonic), drowsiness
Myoclonic: sudden jerk of face or limb or trunk - may suddenly fall to the ground or violently disobedient limb
Atonic: sudden loss of muscle tone causing a fall but no LOC
Describe the phases of features of epilepsy
- prodromal
- early-ictal
- ictal
- post-ictal
Prodromal
- Subjective feeling or sensation that occurs before the onset of a seizure
- Confusion, irritability, mood disturbances
Early-ictal
- Aura is the earliest sign of seizure activity and refers to subjective symptoms experienced by the patient
- Sensory, cognitive, emotional or behavioural changes
- Not all patients experience an aura
Ictal phase
- Highly variable depending on the seizure type
- Seizure generally refers to the generalised tonic-clonic seziure
- Stiffening & rhythmic jerking of the limbs
- May be associated with urinary incontinence and tongue biting
- Usually lasts 1-2mins
- When a single seizure lasts >30m in duration or if 2 seizures occur without regaining consciousness in between - status epilepticus - medical emergency
Post-ictal phase
- Recovery period when seizure has finished
- Altered consciousness, confusion, memory loss, drowsiness or general malaise
- May last hours
What things would you ask when taking a history of a patient with suspected epilepsy?
- description from a witness is useful
- ask specifically about tongue-biting and slow recoveries
- if a first seizure, ask about funny turns or odd behaviour
- deja vu and odd episodic feelings of fear may be relevant
Investigations for epilepsy
Neuroimaging and EEG can help support the diagnosis
EEG: records electrical activity of the brain and assesses risk of seizure recurrence and determines type of seizure
Neuroimaging: MRI can look for structural abnormalities which can cause certain types of epilepsy (essential in those <2)
Management of epilepsy: education and safety
- Driving
- Water safety: seizure while in water can be life-threatening - use buddy system and showers instead of baths
- Fire safety: careful with heat or flames
- Environmental safety: arranging home or work environment to be safe incase of seizures
- Other: care with heights, high risk recreational activities, contraception for medications etc.
Managing acute seizures
First-line
- Benzodiazepines are the cornerstone for initial seizure treatment
- Lorazepam, diazepam, midazolam - adults
Second-line
- Further single dose of benzodiazepines within 10-20m if seizures not controlled
Third-line
- Require loading of second line AED if seizure not controlled
- Phenytoin
- Sodium valproate
- Levetiracetam
Basic seizure first aid
Stay - remain with the patient until recovery, note time and call for help if needed
Safe - keep the patient safe, move or guide away from harm
Side - turn patient on their side, keep airway clear, cushion head and loosen tight fitting clothes
Don’t - restrain or place items in mouth
Consider - rescue medications if a trained medical professional or trained carer (buccal midazolam or rectal diazepam)
Call - 999 if seizure >5m or no return to normal state, injured, pregnant or sick, first seizure, repeated seizures, difficulty breathing or seizure in water.
Name some common AEDs
Sodium valproate - teratogenic!
Carbamazepine - sodium channel antagonist - teratogenic risk
Lamotrigine - sodium channel antagonist - teratogenic risk
Levetiracetam
Phenytoin - sodium channel antagonist - teratogenic!
First line treatment for focal seizures?
Carbamazepine or lamotrigine
First line treatment for generalised tonic-clonic seizures?
Sodium valproate or lamotrigine
First line treatment for absent seizures?
Ethosuximide or sodium valproate
