Epilepsy Flashcards
Focal vs generalised seizures
Focal:
- limited to one hemisphere
- divided into those with retained awareness or impaired awareness
Generalised:
- bilateral networks
- divided into motor and non-motor (absence) seizures
Define epilepsy
> =2 unprovoked seizures occurring > 24h apart (recurrent risk > 60%)
or 1 unprovoked seizure and probability of further seizures occurring >=60% over next 10 years
or diagnosis of an epilepsy syndrome
Convulsive status epilepticus
Prolonged seizure >= 5 minutes or recurrent seizures without recovery in between
Causes of epilepsy and incidence
Cause only found in 1/3
1) Structural: stroke, congenital, acquired
2) Genetic eg. Dravet syndrome
3) Infectious: TB, cerebral malaria, HIV, Zika
4) Metabolic: porphyria, pyridoxine deficiency
5) Immune: anti-NMDA receptor encephalitis
Highest risk in infants and > 50y
Lifetime risk of epilepsy = 3%, 5-10/1000
Lifetime risk of single seizure = 10%
Prognosis in epilepsy
80% with childhood absence epilepsy will be in remission by adulthood
In children and adults 70%% will be in remission - seizure free for 5y on or off treatment
Predictors :
- number of seizures in first 6 months
- response to antiepileptic treatment
When can you consider withdrawing antiepileptic medication?
Seizure free for > 2 years - reduce over 3 months (longer if bentos / barbiturates), if on multiple do one at a time.
- can;t drive for 6 months after stopping treatment or if seizures recur
When is epilepsy considered resolved?
Seizure free for past 10y with no antiepileptic treatment for past 5y
Epilepsy risk factors
1) Premature
2) Complicated febrile seizures
3) Genetic condition associated with epilepsy (tuberous sclerosis/neurofibromatosis)
4) Brain development malformations
5) FH
6) Cerebrovascular disease or stroke
7) Dementia and neurodegenerative disorders - Alzheimers 10x increased risk
Seizure investigations
1) ECG for all to r/o cardiac condition that could mimic epilepsy
2) Bloods: FBC, U&E, LFT, BP, glucose
Management of suspected epilepsy
1) First fit clinic - seen within 2 weeks
2) Advice:
- stop driving
- avoid working with heavy machinery, heights, swimming, baths
- lifestyle factors that may lower seizure threshold
- contact GP if further episodes whilst waiting for specialist
- record seizures
- keep diary
- cushion head & recovery position after
- time seizure - 999 if > 5 minutes / recurrent without recovery
Todd’s paralysis
Temporary weakness after seizure, lasting from a few minutes to 36h before resolving
Managing an epileptic seizure
1) Cushion head, remove jewellery and glasses
2) Recovery position once stopped
3) Admit if 1st seizure/recurs after shotrt time/injured/difficult to wake
Tonic-clonic > 5 minutes or > 3 seizures/hour:
1) Buccal midazolam (not licensed < 3m) / rectal diazepam.(not licensed < 1y)
2) 999 if does not respond if does respond and:
- prolonged before treatment given
- history of repeated seizures/Status
- difficulties monitoring
- 1st seizure
3) Specialist review - provide carers with buccal midazolam or rectal diazepam if not already provided
Annual epilepsy review
1) Seizure control
- if seizure recurrence after period of remission -urgent referral within 2 weeks
2) Long-term carbamazepine - risk of osteoporosis - calcium + vitamin D supplements
3) contraception
Contraception options if on enzyme-inducing drugin epilepsy
If on enzyme inducing drug:
1) Medroxyprogesterone acetate injections
2) IUD/levonorgestrel-IUS
If on lamotrigine:
1) Oestrogens may reduce effectiveness of lamotrigine
2) Progestogen only contraceptives can be used without restriction
Anti-epileptic drugs
Cat 1: ensure maintained on specific manufacturers product - phenytoin, carbamazepine, phenobarbital, primidone
Cat 2: clinical judgement depending on seziure frequency and treatment history - valproate, lamotrigine, clonazam, topiramate
Cat 3: can switch manufacturer - levetiracetam, gabapentin, pregabalin, vigabatrin
Anti-epileptic enzyme inducers
- carbamazapine
- phenobarbital
- phenytoin
- primidone
- topiramate
Anti-epileptic non-enzyme inducers
aetazolamide
-clobazam
-gabapentin / pregabalin
-lamotrigine
-levetiracetam
- valproate
- topiramtte
Driving in epilepsy
Inform DVLA of any seizures / blackouts
G1:
1) Epileptic seizures whilst awake and lost consciousness - licence taken away, can reapply when seizure free for 1 year
2) Seizure due to medication change/reduction - reapply when last seizure 6m ago + back on previous medication for 6m
3) First seizure whilst awake and lost consciousness - licence taken away, reapply when no seizure for 6m and DVLA medical advisor indicated there isn’t a high risk of a further seizure
4) Seizures whilst asleep and awake - if seizures for past 3y only when asleep DVLA may allow you to have licence
5) Only had seizures whilst asleep - if > 12m sine first seizure, DVLA may allow you to have license.
6) Seizures that don’t affect consciousness - if only type of seizure has been when fully conscious and aware and able to move and first seizure > 12m ago, may get licence back.
G2:
1) > 1 seizure - need to not have had epileptic seizure for 10y, taken any anti-epileptic drug for 10y and have < 2% risk of anther seizure according to DVLA - reapply
2) One off seizure.- no epileptic sezizure for 5y and no medication for 5y and been assessed by neurologist in past 12m and DVLA agree
What factors increase risk of second seizure following first?
1) Mental health problem - depression, anxiety, psychosis, alcohol/substance misuse
2) Vascular risk factors: DM, HTN, AF
3) Sepsis
Which features of febrile seizure increase risk of epilepsy later on?
1) > 10 minutes
2) Associated with features eg. weakness
When should EEG be offered?
1) History and examination suggests epilepsy - routine EEG while awake
2) Cannot be used to exclude epilepsy
3) If EEG offered after first seizure, should be within 72h
4) Discuss risks vs benefit of using provoking manoeuvres during EEG
5) If EEG normal consider sleep-deprived EEG
6) If routine & sleep-deprived EEG are normal and diagnostic uncertainty, consider 48h EEG
MRI in epilepsy
Offer to all unless idiopathic generalised epilepsy of self-limited epilepsy with centrotemporal spikes
Should be done within 6 weeks of referral
If CI offer CT
Repeat MRI if initial scan suboptimal, new features to epilepsy, idiopathic generalised epilepsy or with centrotemporal spikes which has not responded to 1st- line treatment or if surgery being considered
Who should be offered genetic testing?
1) < 2 years when epilepsy started
2) Clinical features suggestive of syndrome
3) Associated with learning disability, ASD, structural abnormality, unexplained cognitive decline
When should patients be referred to a tertiary service?
1) All within 4 weeks if:
- uncertainty about Dx
- has epilepsy syndrome likely to be drug resistant
- for further assessment or treatments
- wants to participate in research
2) Children, within 2 weeks if:
- < 3 years old
- < 4 years old and have myoclonic seizures.
- unilateral structural lesion
- deterioration in behaviour, speech or learning
Principles of epilepsy treatment
Use mono therapy if possible.
If 1st line monotherapy fails and epilepsy Dx confirmed - try alternative mono therapy - increase dose of 2nd drug slowly whilst maintaining dose of 1st, then if 2nd drug successful slowly wean 1st. If 2nd unsuccessful wean this one and try alternative.
When to start antiseizure medication
1) Once diagnosis of epilepsy confirmed
2) After first unprovoked seizure if:
- neurological deficit
- EEG - unequivocal epileptic activity
- risk of further seizures not acceptable to patient
- structural abnormality on imaging
