Epilepsy (spring) Flashcards
define epilepsy
a chronic disorder characterised by recurrent seizures
A neuronal hyperexcitability disorder arising from excess excitability or disinhibition
what are the different types of seizures and how are they characterised?
- Partial seizures
- Generalised seizures
Most commonly characterised by impairment of motor activity (convulsions), consciousness, perception and/or behaviour
Different types of epilepsy affect these domains to a differing extents.
What’s the difference between a seizure and a convulsion?
Convulsion: ‘A sudden, violent, irregular movement of a limb or of the body, caused by involuntary contraction of muscles’. Does not necessarily have to be epileptic in origin.
Seizure: a convulsion caused by epileptiform brain activity.
What’s the difference between a seizure and epilepsy?
Epilepsy is a disorder that has many symptoms
Seizure is the principal symptom of epilepsy.
why do individuals experience isolated seizures?
Possible triggers of isolated seizure?
how is an isolated seizure related to epilepsy?
as a result of exposure to different stimuli.
Possible triggers of isolated seizure:
- CNS infection/inflammation
- Stroboscopic lighting
- Metabolic dysfunction
- Head injury
- Fever (especially in children)
- Drug-related (prescription and recreational)
An isolated seizure is not considered to be epilepsy but one or more isolated seizures can increase a person’s risk of developing epilepsy
why is premature mortality 2-3 times higher in epilepsy patients?
SUDEP, status epilepticus, accidents as a consequence of seizure, aspiration pneumonia after seizure, drug toxicity and idiosyncratic ADRs and suicides
Co-morbidities of epilepsy?
which patients are Co-morbidities more severe in?
- Cognitive decline (drug and disease-related)
- Anxiety
- Depression
- Agitation, anger and emotional outbursts
- Suicide (5-15x more likely)
- ADHD
- Reproductive problems (male and female)
- Insomnia
- Migraine
Co-morbidities more frequent and severe in refractory patients
name the different seizure types
Generalised: involves the whole brain (e.g. tonic-clonic or absence seizures)
Partial: Just involves one specific brain area
Secondary generalisation: partial seizures can spread to affect the whole brain.
Simple/complex: whether consciousness is impaired/affected.
give the area affected, function affected, and clinical features of each of these seizure types…
generalised
tonic-clonic
myoclonic
absence
partial
describe what happens during generalised tonic-clonic seizures
Limb extension and rigidity, respiration stops, defaecation, micturation and salivation often occur (~1 min).
Followed by violent synchronous jerks (~2-4 mins).
Patient gradually regains consciousness after a few more minutes and is likely to feel confused, ill and disorientated.
describe what happens during generalised absence seizures
Less physically dramatic but may occur more frequently.
Patient typically ceases any action, stares vacantly ahead, unaware of surroundings, dangers, other people.
Patient recovers very quickly with no after-effects.
describe what happens during partial seizures
Seizure discharge begins and typically remains restricted to a local brain area.
Accompanied by simple symptoms (involuntary movements, abnormal sensory experiences) but rarely loss of consciousness.
e.g. Jacksonian epilepsy, psychomotor epilepsy.
why is the decision to treat epilepsy complex?
All current drugs have significant side-effects
A diagnosis of epilepsy has legal ramifications (driving, employment, pregnancy etc.)
Aims of pharmacotherapy for epilepsy?
Render patient seizure-free or minimise number of breakthrough seizures
Maximise quality of life
name Principal treatments for
epilepsy
give their moa
give an example
Sodium channel blockers
- Action potential generation is dependent upon the opening of voltage-gated sodium channels.
- Inhibition of these channels has been found to prevent or ameliorate seizures.
- e.g. phenytoin, carbamazepine, carisbamate, valproate
Enhancement of GABA actions
- Enhancement of GABA-mediated Cl- channels increase inhibition and attenuates seizures.
- e.g. phenobarbitone, diazepam
Others also available (SV2A-mediated, Ca2+ channel effects): i.e. Levetiracetam
Also ketogenic diet and vagal nerve stimulation
