Seizures Flashcards
classification of seizures?
epileptic
and
non-epileptic (NES)-these can be split into organic e.g. hypoglycaemia, syncopal, sleep disorders, TIAs and psychogenic-dissociative seizures, panic attacks, factitious seizures.
most common type of non-epileptic seizure (NES)?
dissociative seizures-these are involuntary, pt has no control over them
some underlying psychological distress-body ‘dissociates’ from the brain in attempt to stop a part. distressing experience from entering the brain. physical response to an emotional reaction.
what part. features of the seizure itself may suggest NES?
duration over 2 mins gradual onset fluctuating course violent thrashing movements side to side head movement asynchronous movements eyes closed recall for period of unresponsiveness
what endocrine blood substance rises in more than 90% of pts following a tonic-clonic seizure?
serum prolactin
gold standard investigation for non-epileptic seizures?
video-EEG
what is status epilepticus?
continuous seizure for 30 minutes or longer, or recurrent seizures without regaining consciousness lasting 30 minutes or longer.
define provoked seizures?
seizures occurring within 1 week of an acute condition e.g. encephalitis, head injury, cerebral infarct, craniotomy and cerebral haemorrhage.
indications for starting anti-epileptic drug treatment after a 1st seizure?
pt has a neurological defecit
brain imaging shows a structural abnormality
EEG shows unequivocal epileptic activity
pt or their family or carers consider the risk of having a further seizure unacceptable.
which anti-epileptic drug treatment may exacerbate absence seizures?
carbamazepine
recommended anti-epileptic drug for absence seizures?
ethosuximide or valproate
if CI or not tolerated, then lamotrigine
recommended anti-epileptic drug for generalised tonic-clonic seziures?
sodium valproate (NOT in women of childbearing age) or lamotrigine
recommended anti-epileptic drug for focal (partial) seizures?
carbamazepine
define epilepsy
disease of the brain in which pt susceptible to recurrent, unprovoked seizures
- although unprovoked, there may be particular triggers e.g. flashing lights, alcohol, but these triggers would not cause seizures in people without epilepsy, unlike other organic problems e.g. hypoglycaemia, hyponatraemia.
e. g. juvenile myoclonic epilepsy-type of primary generalised epilepsy, seizures and jerks often occur on a morning after waking and triggers include lack of sleep, alcohol and strobe or flickering lights.
post stroke, what seziure activity may be seen?
acutely within 1st 24hr patient may develop continuous jerking movements in only the paretic limb, this is NOT epilepsy
can tx with anti-convulsants, but avoid sedating drugs e.g. BZDs as could be very risky alongside other complications pt susceptible to post stroke e.g. swallowing difficulty
long term patients may develop epilepsy
which part of the brain is most susceptible to epileptic activity?
hippocampus
what is a focal seizure?
also known as a partial seizure
sudden onset of electrical discharge restricted to a limited part of the cortex of 1 cerebral hemisphere. can be further characterised according to whether presence of:
aura-smell or auditory hallucination, visual distortion, deja-vu, fear, rising abdominal sensation, tingling. rapid onset contrasts with more gradual seen in migraine patients BUT there is the rarity of a rapidly evolving occipital seizure where aura can then be followed by a headache.
motor features e.g. 1 limb jerking (jacksonian seziure)
loss of awareness or responsiveness e.g. many temporal lobe seizures.
simple partial=pt retains consciousness
complex partial= may have aura. include automatisms e.g. lip smacking, unawareness of surroundings or may wander.
can evolve into bilateral convulsive seizure-secondary generalised seizure.
features of a generalised seizure, and types?
involves both cerebral hemispheres simultaneously, always loss of awareness/consciousness types: tonic-clonic clonic tonic myoclonic absence (petit mal) atonic-loss of motor tone and LOC, pt drops to the floor
features of absence seizures on presentation and on EEG?
loss of awareness
vacant expression for less than 10s, eyelid fluttering, staring
typical attacks never due to acquired lesions e.g. tumours, feature of primary generalised epilepsy
EEG-3Hz spike and wave activity
main pathology causing temporal lobe epilepsy?
hippocampal sclerosis
main RF=childhood febrile convulsions
changes often visible on MRI
1 of the more common causes of refractory epilepsy, may be amenable to surgery-resection of temporal lobe
what RFs for epilepsy might we enquire about in the hx of a pt with seizures?
intracranial infection-meningitis, encephalitis
childhood febrile convulsions-cause hippocampal sclerosis=main pathology responsible for temporal lobe epilepsy. risk of epilepsy increased in patients with febrile convulsions if complex-focal, prolonged and repeated in the same illness
significant head injury
FH of epilepsy
investigations in suspected epilepsy?
blood tests-FBC, U+Es, LFTs, glucose, Ca2+, Mg2+
serum prolactin
12 lead ECG-arrhythmias, QT interval-note px of pt with seizure following alarm clock going off
check drug levels of anti-convulsants in patients with hx of epilepsy
EEG, video-EEG
MRI brain-part. important in focal onset seizures-more likely struct. abnormality e.g. tumour, and in older patients-more likely cerebrovascular problems
driving guidance for epilepsy?
patient must notify the DVLA and must not drive
pt must be seizure free for 1 year before reapplying for their licence
if pt has 1st one-off seizure, musn’t drive for 6 months
if pt has seizures whilst awake and asleep, may qualify for a licence if only attacks you’ve had in last 3 years have been when pt was asleep
if only have attacks when asleep, may qualify for a licence if it’s been 1 year or more since 1st attack
if attacks are not assoc. with LOC and these are the only ones you ever had, may qualify for licence if 1st 1 was 1 yr ago
if bus, coach or lorry licence:
more than 1 seizure, must show haven’t had a seizure and haven’t had any AEDs for last 10 years
if 1 off seizure, must show haven’t had a seizure and no AED for 5 years
If you had a seizure because your doctor changed or reduced your anti-epilepsy medicine, you can reapply when: the seizure was more than 6 months ago
you’ve been back on your previous medication for 6 months
you haven’t had another seizure in that time
features of primary generalised epilepsies?
present in childhood and early adult life
brain structurally normal, but abnormalities in ion channels controlling neuronal firing, abnormalities in NT release and synaptic connections
polygenic with complex inheritence
e.g. childhood absence epilepsy, juvenile myoclonic epilepsy-myoclonic jerks, later followed by gen tonic-clonic seizures, triggers=sleep lack, alcohol, flashing lights.
what additional treatment should be given to women thinking about becoming pregnant and who take anti-epileptic medication?
folic acid 5mg/day, well before pregnancy and throughout 1st trimester
additional treatment during last month of pregnancy for women on phenytoin?
Vit K-to prevent clotting disorders in the newborn
ADRs of sodium valproate?
teratogenic weight gain transient hair loss hyponatraemia convulsions confusion thrombocytopenia tremor can cause hepatic dysfunction and pancreatitis
what is antiepileptic hypersensitivity syndrome?
rare but potentially fatal syndrome assoc. with some AEDs-carbamazepine, phenytoin, phenobarbitol, lamotrigine
symptoms between 1 and 8 wks of exposure: fever, lymphadenopathy, rash, also other systemic signs-haem, renal, liver complications, vasculitis
drug must be WD immediately and pt must not be exposed again
what are interactions between antiepileptic drugs usually the result of?
hepatic enzyme induction or inhibition (CYP450)
when is risk of AEDs used during pregnancy highest?
during 1st trimester
what must women during 2nd half of pregnancy who have a seizure be assessed for before any AED treatment is changed?
eclampsia
what notification is required for pregnant women with epilepsy?
whether taking AEDs or not, should be encouraged to notify the UK Epilepsy and Pregnancy register
what types of seizures may carbamazepine exacerbate?
absence, myoclonic, tonic and atonic
what serious reaction do we worry about when combining sodium valproate and lamotrigine?
serious skin rashes such as Stevens-Johnson syndrome
what monitoring is required for a patient on levetiracetam during pregnancy?
fetal growth
what congenital anomaly is phenytoin associated with?
cleft palate
when can AED treatment be considered to be withdrawn?
if patient has been seizure free for more than 2 years
drugs will be stopped over 2-3months
