2.4 Seizures + Antiepileptic Drugs Flashcards
What are some different causes for “blackouts/funny turns”?
- Syncopal (most common)
- Seizures
- Metabolic (e.g. hypoglycaemia)
- Brainstem stroke
- Psychogenic
A patient has recently blacked out. What sort of history questions do we have for the patient?
- Circumstances? (where were they, what where they doing - coughing, laughing, eating, exercising, voiding)
- Prodrome? (what’s the last thing you remember? any symptoms before LOC?)
- Post-drome? (First memory - ambulance = seizure, wake up = faint - tongue biting (lateral = seizure), symptoms on recovery, weakness on recovery (brainstem stroke?), speed of motor vehicle accident?
You’re taking a collateral history of a patient who has recently fainted. What sort of questions might you have?
- Confirm circumstances
- Vocalisation?
- How did they fall (crumple: vasovagal, stiff: seizure)
- Colour
- How long unconscious?
- Speed of recovery
Which of seizure vs syncope has high-speed vs low-speed car accidents?
- Seizure, contraction of muscles, stomp on accelerator, causes high-speed
- Syncope, take foot off accelerator, low-speed crash
What features are not useful for differentiating syncope from seizure?
- Incontinence
- Twitching
- Injury (other than lateral tongue biting)
- Dizziness
- Eye movements
Signs of psychogenic seizures
- Crying
- Slow onset
- Side-to-side head movement
- Eye closure
Define seizure
Transient occurrence of signs or symptoms due to abnormal excessive or synchronous brain activity
Focal vs generalised seizure
Focal: 1 part of a cerebral hemisphere
Generalised: Rapidly engaging networks, both hemispheres
A patient has 3 seizures within 24 hours. How many seizures does this technically count as?
- One
- Anything within 24 hours is really only one
Define epilepsy (in terms of diagnostic criteria)
- Multiple seizures more than 24 hours apart
Or:
- 1 unprovoked seizure with >=60% chance of recurrence over 10 years
Or:
- When an epilepsy syndrome can be identified
Unprovoked vs acute symptomatic seizure
Unprovoked: no precipitating factors
Acute symptomatic: in response to a recent CNS/systemic insult
What are some different aetiologies of epilepsy?
- Metabolic (usually transient, sometimes hereditary)
- Cortical malformations
- Autoimmune
- Stroke
- Tumours
- Infection (esp. 3rd world)
- Neurodegeneration
- Genetic
M CASTING (Mid Acting)
Which is more likely to cause seizures: low grade or high grade tumours?
Low grade -> tissue is more likely to be functional, thus allowing for abnormal electrical activity
Describe generalised seizures
Begin at some area in the brain, but rapidly engage bilaterally
Describe focal seizures
Seizure that begins in one area on one side of the brain. May eventually spread.
What is developmental epileptic encephalopathy?
Group of syndromes characterised by:
- Epilepsy
- Developmental delay/impairment
- Cognitive impairment
List some causes for developmental epileptic encephalopathy
- Perinatal stroke
- Infections
- Trauma
Describe genotypic- phenotypic variability in the context of epilepsy
A single genotype can produce multiple phenotypes -> so one mutation will not always cause the same type of epilepsy.
Why is “genetic” different to “inherited”
Epigenetics and mutations acquired de novo
List the neurological elements of consciousness
ARMS
- Awareness
- Responsiveness
- Memory
- Sense of self
What is the relationship between clonus and myoclonus?
Clonus is recurrent myoclonus
Outline the simplified seizure classification framework
- Define seizure type (focal vs generalised, tonic, clonic, atonic, myoclonic etc.)
- Try to determine cause (FMHx, imaging, EEG)
- Work out syndrome according to age, seizure type, and investigations
What are the four kinds of idiopathic generalised epilepsy?
- Childhood absence epilepsy
- Juvenile absence epilepsy
- Juvenile myoclonic epilepsy
- Bilateral Tonic Clonic Epilepsy
When do myoclonic seizures most commonly occur?
In the morning, or late at night (when people are tired).
Makes sense; these people are about to go to sleep.
What are hyperkinetic seizures?
Motor seizures excessive, abnormal and often complex motor movements.
List the investigations for a patient who comes in with a first time seizure
-Routine bloods (incl. biochemistry)
- CT + MRI
- EEG
- PET
- Genetics
Does a normal EEG exclude epilepsy diagnosis?
No. Not sensitive enough.
Do we medicate after a first seizure?
- No
- Wait to see if there is another (~30%); no impact on prognosis
Do antiseizure drugs reduce the risk of developing epilepsy?
No; doesn’t treat underlying cause, just treats seizures
What is catamenial epilepsy?
Epileptic seizures at certain times in the menstrual cycle
The mortality of pregnant women with epilepsy is __ times greater than those without it
10 times (imagine Grant Cardone as a pregnant woman having a seizure; that’s the kind of thing he would use in his marketing materials…)
How does initial prescription of antiseizure medication change in the elderly?
- Start lower
- Increase slower
Depression causes a ___ to ___ times higher risk of unprovoked seizure
2-4 times higher
List three common kinds of antiepileptic drugs
- Valproate
- Carbamazepine
- Levetiracetam
What is the first-line treatment for tonic-clonic seizures? How is it cleared? What else can it be used for?
- Valproate
- Hepatically cleared
- Also used for bipolar disorder, pain disorders, and migraine prevention
(All the valorant pros (who ate all the doritos) get epilepsy from too much video games)
Is it safe to give valproate to a pregant woman?
No. Don’t do it.
What are some side effects of valpraote?
- Nausea
- Increased appetite (weight gain)-> Val Pro :)
- Tremor (all the gaming reflexes leaking out)
- Thrombocytopaenia
What is the mechanism of carbamazepine?
Sodium channel blocker
What is the firstline drug given for focal seizures? How is it cleared? What else is it used for?
- Carbamazepine
- Also hepatically cleared
- Also used for bipolar and pain disorders
How does carbamazepine impact liver enzymes?
Increases levels (enzyme induction)
Should you give carbamazepine to a pregnant woman?
No
Carbamazepine side effects
- Drowsiness
- Ataxia
- Nausea/vomiting
(DAN eats too many carbs)
Levetiracetam mechanism
Nobody knows (antifragile tinkering)
How is levetiracetam cleared? What other drugs does it interact with?
- Renally cleared
- No known drug interactions
What are some of the biggest behavioural side effects of levetiracetam?
- Depression
- Emotional lability
- Hostility
- Aggression
- Agitation
How are gabapentin and pregabalin cleared?
Renally
Should you give GABA lookalikes to a pregnant woman?
No. You should not.
What is a common side effect of GABA lookalikes?
Sedation
What needs to be done before deprescribing epilepsy drugs?
- Very good informed consent (seizures, loss of license etc.)
- Do it gradually
