Epilepsy Flashcards
Incidence/prevalence of epilepsy?
50 per 100,000 diagnosed each year
approx 1 in 100 people in the UK have it
most commonly presents in children and the elderly
Prognosis of epilespy?
up to 70% can become seizure free
50% can withdraw medicatiom
20-30% will continue to have seizures despite treatment
Mortality of epilepsy?
2-3x higher than general population
can be due to accidents not just the disease (indirect)
sudden unexpected death in epilepsy (more common in generalised tonic clonic and poor seizure control)
How many different types of epilepsy?
over 40
Definition of a seizure?
episode of neurological dysfunction of abnormal firing of neurones manifesting as changes in motor control
Definition of epilepsy?
Condition of recurrent, spontaneous seizures arising from abnormal, synchronus and sustained electrical activity in the brain
Aetiology of epilepsy?
- idiopathic epilepsy: genetic cause
- symptomatic epilepsy: e.g. head injury or stroke
- up to 50% have no apparent cause
What is the first step of epilepsy diagnosis?
establish if paroxysmal event was actually a seizure
acute symptomatic seizure? e.g. head injury, infection, imbalance etc
Non-epileptic attack from syncope, encephalitis, migraine?
witnesses are very helpful
Updated NICE guidelines on diagnosis of epilepsy?
must be made by a specialist (i.e. neurologist) as other doctors had an even worse misdiagnosis rate
What is the clinical decision of epilepsy diagnosis based on?
- desrcription of attack (footage, witness)
- family history (genetic cause)
- blood tests
- ECG (cardiac cause/syncope?)
- Medication history - illegal drugs can cause seizures, overdose of some drugs can cause seizures, many commonly prescribed drugs can lower seizure threshold)
Tongue biting pattern of seizures?
tonic clonic seizures - patients tend to bite the sides of their tongue
tip of tongue - generally non-epileptic attack disorder
Which drugs can lower seizure threshold?
SSRIs, tricyclics, quinolones, tramadol
Importance of imaging in epilepsy diagnosis?
MRI preferrred to CT - can see structural abnormalities
important in <2s and adults who develop seizures (see a treatable cause)
should be performed within 4 weeks
Role of EEGs in epilepsy diagnosis?
should never be used in isolation
main use is to classify the epilepsy for correct treatment
however: 10% epileptics have normal EEGs, and 2-4% healthy people have abnormal EEGs
Principles of classification of seizures?
- depend on the location and focus on the pathway involved
- patients can have more than one type of seizures
- failure to classify correctly can lead to inappropriate treatment and therefore treatment failure
Two main types of seizures?
Partial and generalised seizures
Types of partial seizures?
- simple partial seizures (maintain consciousness)
- complex partial seizures (lose consciousness)
- with secondary generalisation
Types of generalised seizures?
- tonic/clonic (muscles spasm in tonic, then limb shaking in clonic)
- absence
- myoclonic
- atonic
Common seizure triggers?
fatique, lack of sleep, stress, excess alcohol, flashing lights, excitement, menstruation, missing meals, some medications
NICE guidelines for treatment of epilepsy?
- always intiated by a specialist after diagnosis
- monotherapy to start (low and slow)
- adjunctive treamtent only if monotherapy has failed
- AEDs are not usually started after first seizure
Ideal epilepsy therapy aim?
Single drug
lowest possible dose
minimum side effects
Patient factors that contribute to choice of drug for epilepsy?
- epilepsy syndrome
- seizure type
- co-morbidity
- lifestyle
- gender, age
- preferences of individual/carers
Drug factors that contribute to choice of drug epilepsy?
- side effect profile
- dose
- formulation
- treatment schedule
- interactions
First line drugs for tonic-clonic seizures?
carbamazepine, lamotrigine, sodium valproate, oxcarbazepine