Epilepsy Flashcards
what is epilepsy
a neurological condition characterised by recurrent seizures
>2 seizures
what conditionis commonly associated with epilepsy
cerebral palsy (30% have epilepsy)
apart from epilepsy, what are common causes of recurrent seizures
1 febrile convulsions
2 alcohol withdrawal seizures
3 psychogenic non- epileptic seizures
who do febrile convulsions usually affect
children
what is the cause of febrile convulsions
increased body temperature in response to viral infection
what are the features of febrile convulsions
brief
generalised tonic or tonic-clonic seizure
what indicates a seizure is generalised
immediate LOC
what is a tonic seizure
increased tone
what is a tonic-clonic (grand mal) seizure
repeated contraction-relaxation of muscles
“a convulsive seizure”
who do alcohol withdrawal seizures usually affect
alcoholics who suddenly stop drinking
how do alcohol withdrawal seizures occur
chronic alcohol consumption leads to increased GABA-mediated inhibition of CNS (similar to benzodiazepines) and inhibits NMDA-type glutamate receptors
alcohol withdrawal reverses this (decreased GABA mediated inhibition of CNS and increased NMDA glutamate transmission)
how are alcohol withdrawal seizures prevented
benzodiazepines following cessation of drinking
what are psychogenic non-epileptic seizures
AKA as pseudoseizures
epileptic like seizures without the characteristic electrical discharges
what are psychogenic non-epileptic seizures associated with
mental health problems
personality disorder
what are common subtypes of generalised seizures
1 tonic-clonic seizures (tonic phase of muscle contraction followed by repeated contraction and relaxation of muscles)
2 absence seizures (brief episode of patient appears to be ‘staring blankly’)
3 myoclonic seizures (brief, rapid muscle jerks)
4 atonic seizures (loss of muscle tone and patient falls to the ground)
what are common subtypes of partial seizures
1 simple (no LOC) 2 complex (consciousness disturbed)
what symptoms are associated with seizure
biting tongue
incontinence of urine
what do seizure patients feel after a seizure
a postictal phase (drowsy and tired)
what investigations are standard for a seizure
EEG (electroencephalogram)
MRI
when are antiepileptics given
following a second epileptic seizure
what is the first line treatment for patients with generalised seizures
sodium valproate
what is the first line treatment for patients with partial seizures
carbamazepine!
what is second line treatment for generalised and partial seizures
lamotrigine
what are the guidelines for driving with epilepsy
no driving for 6 months following a seizure
with establised epilepsy, patient must be fit free for 12 months before driving
what is the risk of sodium valproate in pregnant women
teratogenic
what happens when antiepileptics and the contraceptive pill are taken together
efficacy of antiepileptic and oral contraceptive pill is reduced
what is the MOA of sodium valproate
increases GABA activity
what is sodium valproates effect on P450 enzymes
P450 enzyme inhibitor
what is the MOA of carbamazepine
binds to Na channels increasing their refractory period
what is carbamazepines effect on P450 enzymes
P450 enzyme inducer
what is administered to a patient suffering from a seizure which fails to terminate spontaneously
benzodiazepines (diazepam)
what is the condition called what a patient continues to fit following administration of benzodiazepines (diazepam)
status epilepticus
def of seizure
paroxysmal synchronised cortical electrical discharges
what are the motor signs of electrical charges
convulsions
what are the elements of a seizure
prodrome
aura
post-ictally
what is prodrome
not part of the seizure
change in mood or behaviour
lasts hours/days preceding the seizure
what is an aura
part of the seizure
indicated by strange smells or flashing lights (which aren’t really there)
what is the post-ictal phase
period immediately after the seizure
headache, confusion, decreased consciousness
what does an aura imply
focal seizure
aetiology
1 idiopathic (majority) 2 structural 3 others
what are the structural causes of epilepsy
cortical scarring (head injury years before onset of epileptic seizures) space-occupying lesion stroke infection (meningitis, encephalitis) inflammation (vasculitis)
what are non-epileptic causes of seizures
trauma
stroke
alcohol or benzodiazepine withdrawal
metabolic disturbances
what metabolic disturbances can cause seizures
hypoxia high/low Na low Ca high/low glucose uraemia
pathogenesis
seizures occur due to an imbalance between inhibitory and excitatory currents or neurotransmission in the brain
triggers promote excitation of the cerebral cortex and induce a seizure
however many seizures begin without an obvious trigger
what triggers could start an epileptic fit
flashing lights
drugs
sleep deprivation
epi
common
in children and elderly
history
obtain history from patient and witness of seizure
1 information about the seizure -onset? duration? -LOC? incontinence or tongue biting? -limb-jerking? -post-ictal period? 2 determine whether it is a focal or generalised seizure 3 triggers?
what features are suggestive of a seizure
tongue biting
slow recovery
what history would be associated with a frontal lobe focal motor seizure
motor convulsion
jacksonian march (spreading of focal motor seizure with no LOC)
post-ictal weakness (todds paralysis) in one part of the body
what history would be associated with a focal temporal lobe seizure
LOC with no memory of seizure
aura (fear or deja-vu)
hallucinations (smell or taste something which isn’t there)
what history would be associated with a focal frontal lobe complex partial seizure
LOC
rapid recovery
what is a simple seizure
a seizure which does not result in LOC
what history would be associated with a tonic-clonic (grand mal) seizure
LOC
tonic phase (generalised muscle spasm)
followed by clonic phase (repetitive synchronous jerks)
associated with tonic-clonic seizures is faecal/urinary incontinence or tongue biting
in the post-ictal phase there is reduced consciousness, lethargy, confusion
what history would be associated with a absence (petit mal) seizure
common in childhood
LOC but maintenance of posture (patient stars blankly into space for seconds)
no postictal phase
what history would be associated with a non-convulsive status epilepticus
acute confusional state
examination
normal between seizures
what is a partial seizure
focal onset (features of seizure limited to one area of the brain)
what is a simple partial seizure
no LOC
focal motor + sensory symptoms
no post-ictal symptoms
what is a complex partial seizure
LOC
most commonly arise from temporal lobe
post-ictal confusion is common with temporal lobe partial seizure
rapid recover from seizure suggests focal seizure in which lobe
frontal
what is a primary generalised seizure
silmultaneous onset of electrical discharge throughout the cortex
what symptoms would be seen in a partial (focal) seizure of the parietal lobe
sensory disturbances
motor symptoms
investigations
1 bloods
-prolactin increases for a short amount of time after a ‘true’ seizure
2 EEG
-for diagnosis
3 imaging
-for structural, space-occupying + vascular lesions
management
1 with recurrent seizures (>2) begin medication (dependent on seizures type)
what medication is used for generalised tonic-clonic seizures
sodium valproate or lamotrigine are 1st line
what is the advantage of lamotrigine over sodium valproate
less teratogenic
what medication is used for absence seizures
sodium valproate or lamotrigine
what medication is used for tonic, atonic, myoclonic seizures
sodium valproate or lamotrigine
what medication should be avoided with tonic, atonic, myoclonic seizures
carbamazepine
may worsen seizures
what medication is used for partial seizures
carbamazepine
1st line treatment
what dosages of drugs should be given
minimum dosage to control seizures
slowly build up doses over months
what is the procedure for changing to a different anti-epileptic drug
introduce new drug while maintaining original
withdraw the original drug once the new drug is established
what is status epilepticus
seizure>30mins with failure to regain consiousness
management of status epilepticus
resuscitate + ABCDEF
IV lorazepam or PR diazepam
if no change, IV phenytoin
what are the risks of AEDs
teratogenic
can limit effectiveness of oral contraception
complications
trauma from tonic-clonic seizures
sudden death in epilepsy (SUDEP)
what are the complications of AEDs
gingivial hypertrophy with phenytoin
neutropenia or osteoporosis with carbamzaepine
prognosis
remission is common
