Epilepsy Flashcards
what is a seizure?
sudden change in behaviour caused by electrical hypersynchronisation of neuronal networks in cerebral cortex. Can be provoked or unprovoked
provoked seizures
occurs at time of systemic or brain insult
metabolic derrangements
drug or alcohol withdrawal
acute neurological disorders
what neurological disorders can cause seizures?
stroke
encephalitis
acute head injury
unprovoked seizures
unknown aetiology
pre-existing brain lesion or progressive neurological disorder
what are the 2 types of seizures?
generalised or focal
focal seizures
originate in 1 hemisphere
can evolve to generalised
2 types = simple focal or focal dyscognitive
simple focal seizure
retained awareness
focal dyscognitive
consciousness is impaired at onset but otherwise the same as simple focal
generalised seizures
both hemispheres
bilateral discharges involve subcortical structures
impairment of consciousness
different types
what are the different types of generalised seizures?
absence myoclonic atonic clonic tonic tonic-clonic
absence seizure
act lost
myoclonic seizure
sudden burst of activity causing jerking once
atonic seizure
loss of muscle power and tone
tonic-clonic seizure
stiffness and repetitive limb shaking
gelastic seizure
giggling at start
then limb and head jerking
simple focal occipital seizure
multi-coloured flashing colours
short-lived
no lasting effect
Temporal lobe seizure
most common complex aura visceral disturbance deja vu jamais vu memory automatisms affective disturbance - fear, pleasure, elation, supernatural
frontal lobe seizure
motor cortex affects
jacksonian march
paralysis
fencing posture - contralateral head movement and arm extension with flexion of ipsilateral arm
lasting weakness while repolarisation occurs
what is the jacksonian march?
discharge propagates through cortex
todds paralysis
post - ictal paralysis
what is automatism?
repetitive movements, e.g. lip smacking
what is jamais vu?
strange feeling
parietal lobe seizure
paraesthesia and tingling
motor symptoms
jacksonial match
occipital lobe seizure
unformed images and flashing lights
complex visual hallucinations
post-ictal blindness - temporary
primary generalised seizures
Tonic-clonic seizure phases
phases of primary generalised seizures
- abrupt loss of consciousness
- epileptic cry
- tonic phase
- clonic phase
- postictal
what is the epileptic cry?
tonic contraction of respiratory muscles
what happens in the tonic phase?
lasts less than 1 min rapid neuronal discharge all muscles of arms, legs, chest and back become stiff eyes open pupils dilated elbows fixed arms pronated legs extended teeth clenched breath held
what happens in the clonic phase?
1-2 mins slow neuronal discharge muscles begin to jerk and twitch rhythmically tongue biting incontinence - loss of sphincter tone bloody sputum mouth frothing eyes roll back or forwards
what happens in the post ictal phase?
deep sleep
confusion
agitation
absence seizures features
usually during childhood 5-10 seconds of vacant staring often occur in clusters 95% remission during adolescence affect education
what can bring on an absence seizure?
hyperventilation
phonic stimulus
myoclonic seizure
sudden generalised muscle contractions
normally occur on the edge of sleep in healthy people but when they occur during the day epilepsy can be diagnosed
can develop into tonic-clonic seizures
need lifelong treatment with antiepileptics
pathophysiology of provoked seizures
insult causes infiltration of inflammatory cells which react with microglia and astrocytes
alters function of neurone membrane and causes hyper-excitation of neurones which spreads through the brain
what brain injuries can cause provoked seizures?
- stroke – haemorrhagic
- subdural haematoma
- subarachnoid haemorrhage
- traumatic brain injury
- hypoxic ischaemic injury
- brain abscess
- meningitis
- encephalitis
- neoplasm
- vascular malformations
medical illnesses that cause provoked seizures
- hypoglycaemia – insulin dependants
- hyperglycaemia – nonketotic hyperglycaemia
- hyponatraemia – rapid fall
- hypocalcaemia – more likely with neonates
- hypomagnesemia
- hyperthyroidism
- uraemia – renal failure causing myoclonic seizures
- alcohol withdrawal
- acute intermittent porphyria
- drugs
what drugs can cause provoked seizures?
cocaine
amphetamines
MDMA
tricyclic antidepressants
aetiology of seizures
vascular infections trauma/ toxins autoimmune metabolic imbalances idiopathic neoplasm syndromes
how to diagnose epilepsy?
presenting features
history
investigations
differential diagnostic investigations - ECG to ensure blackout is not cardiac
history taking for a seizure
description of events and circumstances video footage if possible what happened beforehand - tiredness/ triggers etc. past medical history drug history
what drugs can cause a seizure?
tramadol neuroleptics vasodilators older anti-depressants amitriptyline - prolongation of QT interval
red flags of seizures
eyes open tongue biting on side cyanosis retrograde amnesia hot feeling unwell feeling stretuous breathing loss of consciousness incontinence - urine and faeces postictal recovery lasting neurological features - odd sensation and tingling
post-ictal state
pain
injuries
exhaustion
investigations for seizures
may be absent of clinical findings look for structural or metabolic causes eliminate differential diagnoses MRI EEG CT scan lumbar puncture
Fever fit
doesn’t normally develop into epilepsy
fainting vs seizure
fainting can appear like a seizure but recovery tends to be much quicker
EEG tracing
done over 24-48 hours to eliminate non-epileptic episodes caused by psychosocial factors
what are the differential diagnoses for seizures/ epilepsy
syncope vasovagal syncope with reflex anoxic event cardiac arrhythmia non-epileptic attack/ pseudoseizures maligering migraine dissociative attack
vasovagal syncope with reflex anoxic event
short burst of activity occurs alongside syncope
cardiac arrhythmias causing syncope
brugada syndrome
hypertrophic obstructive cardiomyopathy
prolonged QT interval disorders
non-epileptic attacks
functional neurology
not explained by structural or organic pathology
what is maligering
alternative motive for a seizure - mimicing
what causes dissociative attacks?
psychological causes
QT elongation
can cause a blackout
what drugs prolong the QT interval?
antiarrhythmic drugs
certain non-sedating antihistamines - terfenadine
macrolide antibiotics
psychotropic medications
gastric motility agents/ anti-emetics - cisapride and domperidone
what is brugada syndrome?
prolonged PR interval RBBB can be fatal ST elevation inherited condition causes a blackout that appears like a seizure requires defibrillator insertion
principles of epilepsy treatment
epilepsy nurse specialist
education of patient and the family
first aid
antiepileptic - given on 2nd seizure
when to treat someone on the first seizure?
60% risk over 10 years if:
- abnormal EEG
- structural lesion
- abnormal neurological examination
- first fit occurs during sleep
driving and epilepsy
everyone who has suffered an unprovoked seizure should contact DVLA and surrender their licence
how much time do people have to have off driving after a seizure?
1st seizure = 6 months- 1 year off depending on other factors
HGV driving = 10 years off driving after 1 seizure
established epileptics have to be seizure free for 12 months before being allowed to drive
precautions for epileptics
shower not bath, if bathing keep door open and ask someone to be aware
swimming either accompanied or let lifeguard know
avoid triggers
SUDEP
sudden unexplained death in epilepsy
sudden unexplained death in epilepsy
very rare
risk reduced with anticonvulsants
generalised seizure spreading through brainstem and life-maintaining areas
need to educate and reassure patients that it is rare
common seizure triggers
sleep deprivation alcohol drugs missed anticonvulsants pregnancy infections illness vomiting/ diarrhoea
when does alcohol cause seizures
on withdrawal
what drugs can cause seizures?
amphetamine
ecstasy
cocaine
enzyme inducers
why does pregnancy cause seizures?
enlarged volume of distribution reduces efficacy of anticonvulsants
or separately as eclampsia
what infections commonly cause seizures?
UTIs
URTIs
why does illness cause seizures?
poor absorption of anticonvulsants
first aid for seizures
protect head remove glasses loosen tight clothing turn on side/ recovery position don't put anything in their mouth look for ID and/ or medialert don't hold them down offer support and help after seizure not everyone with epilepsy needs hospital admission after seizure
when is hospital admission needed?
> 5mins long seizures anyone with or without epilepsy needs hospital admission
principles for epilepsy treatments
aim for monotherapy
start slow and titrate up slowly
50% will be successfully treated with the 1st drug
adjuvant sometimes required
surgical intervention preserved for non-responders
consider tetragenicity
pregnancy and epilepsy drugs
sodium valporate cannot be used in child-bearing aged women
carbamezapine is tetragenic
polypharmacy increases risk of tetragenicity
what do anticonvulsants cause in fetuses?
psychomotor abnormalities
developmental delay
what are the treatments for generalised tonic clonic seizures?
carbamezapine
lamotrigine
sodium valporate
what drug can be used for epilepsy during pregnancy?
lamotrigine
what are the treatments for tonic/ atonic seizures?
sodium valporate
don’t use carbamezapine
treatment for absence seizures
ethosuximide
lamotrigine
sodium valporate
don’t use carbamezapine
treatment for myoclonic seizures
levetiracetam
sodium valporate
don’t use carbamezapine
treatment for focal seizures
carbamezapine
sodium valporate
lamotrigine
levetiracetam
side effects of sodium valporate
hepatic toxicity thrombocytopenia weight gain systemic lupus erythematosus pancreatitis decreased bone marrow density liver inhibition
side effects of carbamezapine
dose related headaches ataxia nausea allergic reaction hyponatraemia dermatitis stevens johnsons syndrome liver inducer
side effects of lamotrigine
stevens johnsons syndrome
allergic reaction
side effects of ethosuximide
weight loss
nausea
psychological disturbance
anticonvulsants interactions
carbamezapine, sodium valporate and phenytoin can itnerfere via liver induction or inhibition with oral contraceptives and anticoagulants
monitoring of anticonvulsants
requires LFT monitoring
blood test before starting treatment and then repeat afterwards
rescue therapy for seizures
buccal midazolam - can be administered by family if trained for emergency purposes
rectal diazepam
IV lorazepam in hospitals for severe seizures
midazolam
rohypnal - date rape drug
causes drowsiness and amnesia
what is status epilepticus?
> 5mins of continuous seizures or more than 2 discrete seizures between which there is incomplete recovery of consciousness
risks associated with status epilepticus
risk of brain damage due to hypoxia and cytotoxicity from chemicals released during seizure
can be fatal
causes of status epilepticus/ seizures
structural brain injury anti-epileptic non-compliance withdrawal metabolic abnormalities overdose of medication that can lower seizure threshold
what overdose can cause seizures?
insulin
other treatments for epilepsy
ketogenic diet sativex cannabinoid acetazolamide epidiolex - cannabinoid CBD oil vagal nerve stimulator neurosurgery
ketogenic diet
helpful for children and likely adults as well
sativex
cannabinoid
used for MS spasticity
not funded
acetazolamide
anti-diuretic
used for menstrual related seizures
epidiolex
cannabinoid
used in childhood for complex epileptic syndromes
vagus nerve stimulator
electrodes attached to vagus nerve which send impulses up vagus nerve to grey matter to terminate the seizure
can be activated by patient or someone else if the patient feels a seizure coming on
can work through a feedback sensor
expensive
epilepsy neurosurgery
resection of the area if focal
what are the types of epilepsy neurosurgery?
temporal lobectomy extratemporal resection lesionectomy hemispherectomy corpus callostomy multiple subpial transection
temporal lobectomy
cutting away of brain tissue in temporal lobes that cause seizures
extratemporal resection
removal of parts of the brain other than temporal lobe that causes seizures
lesionectomy
tumours, abscesses or other damage causing seizures can be removed
if resection is not possible
disconnect parts of the brain from each other to prevent spreading of seizures
hemispherectomy
outer layer of 1 half of brain removed
corpus callostomy
connections between hemispheres are cut to stop seizures spreading from 1 hemisphere to the other
multiple subpial transection
nerve fibres in the outer layers of the brain are cut
stops seizures spreading
how does sodium valporate work?
blocks voltage gated sodium ion channels
increases availability of GABA
