Epilepsy Flashcards
What are important features when taking a history from a patient with suspected epilepsy?
Onset - what were they doing? Light-headed or other syncopal symptoms? What did they look like? (breathing, posture, head turning)
Event itself - type of movements (tonic, clonic, rigor), responsiveness and awareness throughout
Afterwards - speed of recovery, sleepiness/disorientation, deficits
What are some risk factors for epilepsy that need to be asked about in a history?
Birth, development, seizures in past, head injury, family history, drugs and alcohol
How is a patient with suspected epilepsy examined?
Don’t usually examine in 1st seizure clinics - history is most important.
If diagnosis of syncope - cardiovascular examination and lying + standing BP important
How is patient presenting with a fall investigated?
ECG - mandatory!
Imaging - MRIb vs CTb
Electroencephalogram (EEG)
When does a patient get a CT scan acutely?
Clinical or radiological skull fracture, deteriorating GCS, focal signs, head injury with seizure, failure to be GCS 15/15 4 hours after arrival, suggestion of other pathology e.g. SAH
Why is EEG used?
Classification of epilepsy, confirmation of non-epileptic attacks, surgical evaluation, confirmation of non-convulsive status
What are the laws surrounding driving and a patient’s 1st ever seizure?
6 month ban from driving a car
What is the law for driving a car in a patient with diagnosed epilepsy?
Must be seizure free for 1 year or 3 years if the seizure was during sleep
What is an epileptic seizure?
Abnormal synchronisation of neuronal activity - usually excitatory with high frequency action potentials, sometimes predominantly inhibitory i.e. either too much excitation or too little inhibition Interruption of normal brain activity - focal or generalised Usually brief (secs-mins)
How common is epilepsy and in what age group is it most common?
Incidence 50-80/100,000
Any age but most common in infancy and old age
What does this diagram represent in terms of epilepsy?
Demonstrates that a generalised seizure could start at different points in the network and engage bilaterally distributed networks.
Key point = generalised seizures can start from a focal point
How are partial epileptic seizures classified?
Simple - without impaired consciousness
Complex - with impaired consciousness
How are generalised epileptic seizures classified?
Absence, myoclonic, atonic, tonic, tonic clonic
What are the motor symptoms associated with partial seizures?
Rhythmic jerking, posturing, head and eye deviation, other movements e.g. cycling, automatisms e.g. plucking, vocalisation
What are the sensory symptoms associated with partial seizures?
Somatosensory, olfactory, gustatory, visual and auditory
What are the psychic symptoms associated with partial seizures?
Memories, deja vu, jamais vu, depersonalisation, aphasia, complex visual hallucinations
When does generalised epilepsy typically present and what is the underlying mechanism?
Present in childhood and adolescence.
Generalised spike-wave abnormalities on EEG
Most have genetic predisposition
How is primary generalised epilepsy treated?
Sodium valproate is treatment of choice but is teratogenic, lamotrigine is an alternative
Name an example of primary generalised epilepsy
Juvenile myoclonic epilepsy - early morning jerks, generalised seizures, sleep deprivation is a risk factor
When does focal onset epilepsy typically present and what is the underlying mechanism?
Onset at any age.
Underlying structural cause
Focal onset, can then generalise
What are the features of focal onset epilepsy and how is it treated?
Frequent - complex partial seizures with hippocampal sclerosis
Treatment - carbamazepine or lamotrigine (sodium valproate is not first line due to side effects)
Some AEDs target voltage-gated Na channels because Na influx increases excitability and drives APs. Name some examples of these drugs
Na channel antagonists - carbamazepine, oxcarbazepine, phenytoin, lamotrigine, topiramate, zonisamide
Some AEDs target voltage-gated K channels because K efflux reduces neuronal excitability. Name some examples of these drugs
K channel agonists - retigabine
Some AEDs target voltage-gated Ca channels because Ca influx triggers neurotransmitter release. Name some examples of these drugs
Ca channel antagonists - pregabalin and gabapentin (also ethosuximide)
