EPILEPSY Flashcards
What is epilepsy?
ongoing susceptibility to recurrent epileptic seizures
What are epileptic seizures?
sudden synchronised discharge of cerebral neurones causing symptoms or signs that are clear to patient or observes
What are primary causes?
- epilepsy syndromes, usually genetic causes
- neurodegenerative e.g. parkinsons
What are acquired causes?
- excitatory/inhibitory receptors can be effected by infection/tumours/injury
What are electrolyte causes?
drugs can reduce seizure threshold
alcohol has inhibitory effect in the brain as it up regulates excitatory neurotransmitters
What drugs can reduce seizure threshold
- antimicrobials e.g. beta-lactams, chloroquine
- antipsychotics - clozapine
- antidepressants - trycilic antidepressants (in overdose)
How do beta lactams reduce threshold?
- mainly in high doses for infections in CNS
- penicillin
How does anti-tuberculosis reduce threshold?
- inhibits formation of GABA
- increased excitatory neurotransmission
What is generalised seizures?
whole brain
What does antipsychotics need to be coprescribed with and why?
- anti-epileptics because the risk of stopping antipsychotics are too high
What is focal (partial) seizure?
focus of electrical activity in one hemisphere or one lobe
What are the different focal seizures and describe them
simple: dont lose consciousness
complex: lose consciousness
what is secondary generalisation
when focal seizures develop onto general seizures
What are the different types of generalised seizures?
tonic-clonic: alternating stiffening
tonic: stiffening
myoclonic: muscle contractions, often rhythmic, involuntary
Atonic: drop seizures
abscence seizures: involves both sides of brain, begins in childhood - loss of awareness for under 10yo
What is Jacksonian march?
starts in one place and spreads throughout the limb
What is Todd’s paralysis?
temporary paralysis of the limb
What are the characteristics of tonic phase in tonic-clonic seizures?
Tonic(10-20s) - funny feeling
- tonic stiffening which can cause patient to dall
- larynx contracting
- cyanosis (bluish/purple skin) due to respiratory impairment
- tonic contractions of jaw leading to tongue biting
- increases sympathetic activity (tachycardia + hypertension)
What are the characteristics of the clonic phase in tonic-clonic seizures?
- 1 min
-convulsions (discharges in brain are being disrupted by small periods of relaxation) - eyes open/tongue biting
- urine/faecal incontinence
What is the post-ictal?
- lasts 1-2 hrs
- flaccid unresponsiveness
- drowsiness &confusion
What is status epileptics?
continuous seizure longer than 5 mins
- failed to terminate
What are the investigations for epilepsy
blood tests, MRI, EEG, safety advice: avoid swimming or baths or working at heights
stop driving
What is syncope
describes loss of consciousness for a short period of time
What is the difference between seizure and syncope
in syncope there is no tongue biting, pallor, prolonged standing and rapid recovery
whereas in seizure there is post-ictal confusion, longer recover, during there is tongue biting and cyonosis
Why is it difficult to withdraw epileptic treatment?
50% chance of recurrence
What is refractory epilepsy?
when anti epileptics are no longer controlling the seizures
When is surgery necessary
if there is a focus of epilepsy e.g. tumour
When do you consider to remove antiepileptic drugs?
if seizure free for over 3 years
Why is it dangerous to take anti-epileptics for pregnant women?
they can be teratogenic - causes fatal abnormalities
lamotrigine is the safest
