Epilepsy Flashcards
what is the prognosis of epilepsy?
Up to 70% can become seizure free.
50% can withdraw medication
20-30% will continue to have seizures despite treatment
what is the mortality of epilepsy?
Rate 2-3 times higher than general population
Accidents due to the seizure
Can be due to accidents as well as disease itself
SUDDEN UNEXPECTED DEATH IN EPILEPSY (SUDEP)
Dies due to a seizure and when there is NO other cause found to cause the death, due to convulsion cardiac or respiratory restriction
what is a seizure?
A SEIZURE is an episode of neurological dysfunction of abnormal firing of neurones manifesting as changes in motor control/sensory perception/behaviour/autonomic function
what is epilepsy?
EPILEPSY is the condition of recurrent, spontaneous seizures arising from abnormal, synchronous and sustained electrical activity in the brain.
what is the aetiology of epilepsy?
Idiopathic epilepsy – genetic cause around 40%
Symptomatic epilepsy (e.g. Head injury/stroke)
Up to 50% have no apparent cause
Up to 40% may have a genetic component
what is the diagnosis of epilepsy?
faints, fits and funny turns
- First step of diagnosis is to establish if paroxysmal event was actually a seizure or something else.
-Lack of sodium
-Acute symptomatic seizure - Caused by direct ‘insult’
E.g. Head injury, infection, biochemical imbalance - Non-Epileptic attack disorder? Migraines? Encephalitis? Syncope?
- Faint and limb twitching
- Good history taking and witnesses are useful
- Epilepsy is spontaneous and recurrent.
what is best at imaging for a seizure?
MRI as it can show structural abnormalities (bleed)
what are the two main types of seizures?
- focal
- generalised
what are the different types of focal seizures?
- Simple focal seizures – may become aggressive
- Focal seizures with impaired awareness - may get a warning before and then zone out and then rhythmic movements. Can spread to the whole brain
what are the different types of generalised seizures?
- Tonic/Clonic = tonic phase is where all the muscles tense up, the diaphragm tenses so patient may let out a cry. The clonic phase is when you have chronic shaking of limbs, usually on the floor. Usually self terminate within 2-3 minutes. Then they will have a post phase – extremely exhausted and sleep for a long period of time
- Absence – can be very short (seconds)
- Myoclonic – limb jerking. Occurs during waking hours and interferes with day to day life
- Atonic – drop attacks, looses all control and falls to the ground
what are common triggers?
Fatigue Lack of sleep Stress Alcohol in excess Flashing lights (photosensitive epilepsy) - 5% Excitement Menstruation – catamenial epilepsy Missing meals Some medications
what are the NICE guidelines ?
Always initiated by a specialist, after a diagnosis
Monotherapy should be used where possible
Start low, go slow titration until we have control or maximum side effects
Adjunctive (add on) treatment should only be considered when monotherapy has failed
Two or three drugs before you would try add on therapy
AEDs are not usually started after a first seizure
Quite a lot of people have 1 seizure, we would then refer them to get the bigger picture
EEG confirms epileptic seizure you may start one straight away
what is the aim of treatment?
- single agent
- at the lowest dose
- with the minimum side effects
what patient factors do you need when deciding therapy?
- Epilepsy syndrome
- Seizure type
- Co-morbidity
- Lifestyle
- Gender
- Age
- Preferences of individual/family/carers
what drug factors do you need to take into account when chosing therapy?
- Side effect profile
- Dose
- Treatment schedule
- Formulation
- Interactions
what is sodium valporate?
first line in many seizure types
600mg 1-2 times a day and increase gradually over time
when should sodium valporate be avoided?
Should be avoided in pregnant women and women of childbearing potential due to risk of neurodevelopmental defects.
Higher risk of child having neurodevelopmental defects
Only reason we would use this in a young lady is if we have tried everything else, but they need to know all the risks of being on this
what do you need to monitor in sodium valporate admin?
Monitor for signs of liver, blood, pancreatic disorders
You may get initial spike in LFTs when starting this
Clotting disorders so need to keep an eye on platelet
Severe abdo pain and nausea and vomiting need to be reviewed
what are the side effects of sodium valporate?
nausea, gastric irritation, diarrhoea, weight gain, hair loss (grows back curly)
what is carbamazepine?
1st line treatment for focal seizures
Initially 100-200mg 1-2times daily increased slowly every 2 weeks.
what do you need to monitor in carbamezapine?
monitor for blood, liver and skin disorders
what are the side effects?
Side effects – Headache, N+V, drowsiness, dizziness, rash, ataxia (staggering, appear drunk), hyponatraemia (low sodium)
Dose related, can be dose limiting
Can be reduced by using MR tabs
what is lamotrigine?
used for focal and generalised seziures
initially 25mg/day and slowly titrated every 2 weeks
what are side effects?
serious skin disorders
nausea, vomiting, diarrhoea, dry mouth, skin reactions. Steven Johnson syndrome (blister on mucus membranes – life threatening)
what is levetiracetam?
Used for partial seizures and adjunctive therapy for myoclonic seizures and tonic-clonic seizures
250mg/day, increased every 1-2 weeks to max 1.5g BD
what is the side effects of levetiracetam?
Nasopharyngitis, somnolence, fatigue, dizziness, headache
what is phenytoin?
not recommended by NICE
role in refractory seizures
narrow therapeutic window
why is phenytoin rarely used?
Extensive hepatic metabolism -
Strong inducer of CYP450 – interactions reduces effect of oral contraceptive pill
Highly protein bound – albumin. Unbound fraction that crosses blood brain barrier and has the effect. Low albumin will have toxicity at normal levels, so you might need to just take the unbound level
what are the 3 categories of antiepileptics?
• Category 1: Includes phenytoin, carbamazepine, phenobarbital,
Specific measures are necessary to ensure consistent supply of a particular product
• Category 2: Includes sodium valproate, lamotrigine, oxcarbazepine
The need for continued supply based on clinical judgement
• Category 3: Includes levetiracetam, lacosamide, gabapentin
No specific measures required
what is status epilepticus?
- Medical emergency associated with significant morbidity and mortality
- Efficient and effective treatment is key
- Aim of treatment is seizure termination
- Generalised Convulsive Status Epilepticus is defined as a tonic clonic seizure which lasts longer than 30 minutes or repeated tonic clonic seizures within 30 minutes
what is the treatment of status epilepticus?
• IV Lorazepam 0.1mg/kg (usually 4mg), repeated once after 10-20 minutes if seizure continues
o Give usual AEDs if already on treatment
o Alternatives to lorazepam are IV diazepam or buccal midazolam
o Phenytoin IV 20mg/kg over 20 minutes (or phenobarbital if already on phenytoin)
• General anaesthesia if above does not work
what are the problems with combination therapy?
• Drug interactions o Potent inducers/inhibitors of hepatic enzymes o Drug-Drug interactions between AEDs • Increased toxicity o Interactions can increase plasma concentration o Additive side effects • Identifying ADRs o Can be difficult to differentiate • Non—compliance o Increased pill burden o Unpleasant side effects
what happens during treatment withdrawal?
• Joint decision taken by patient and family/carers
• Under the guidance of a specialist
• Must be seizure free for 2 years before considering withdrawal
o Withdrawal must be carried out slowly over months
o One drug at a time if on combination therapy
o A failsafe plan must be in place in case seizures recur.
Last dose reduction is reversed and medical advice sought
