Anticonvulsants Flashcards
Define what is meant by epilepsy
A neurological condition causing frequent seizures
Seizures are “sudden changes in behaviour caused by electrical hypersynchronization of neuronal networks in the cerebral cortex”
What is the relationship between epilepsy and convulsions
Not all seizures involve convulsions
Describe the epidemiology of epilepsy
Prevalence between 2-7% of the population- doesn’t tell you which type of epilepsy- some are more severe than others
Incidence increased over the last 30-40 years - particularly focal lesions- due to traumatic brain injuries.
Describe the diagnosis of epilepsy
Brain activity can be measured using:
Electroencephalography (EEG) - Abnormal electrical activity during and following a seizure can be detected by electroencephalography (EEG) recording from electrodes distributed over the surface of the scalp. Various types of seizure can be recognised on the basis of the nature and distribution of the abnormal discharge
Magnetic resonance imaging (MRI) - identify structural abnormalities and the underlying pathology- can’t tell you whether the patient is having a seizure or not as it doesn’t record electrical activity.
Essentially, what is epilepsy
A tendency to recurrent, unprovoked seizures
Summarise what is meant by a general seizure
Begins simultaneously in both hemispheres of brain
Reticular activating system involved
Immediate loss of consciousness is a key feature.
List the different types of generalised seizures
Tonic-clonic Absence Tonic/Atonic Myoclonic Status Epilepticus
Summarise tonic-clonic seizures
Tonic-clonic seizures: loss of consciousness — muscle stiffening – jerking/twitching – deep sleep — wakes up
What can happen to patients in tonic-clonic seizures
A tonic–clonic seizure consists of an initial strong contraction of the whole musculature, causing a rigid extensor spasm and an involuntary cry. Respiration stops, and defecation, micturition and salivation often occur. This tonic phase lasts for about 1 min, during which the face is suffused and becomes blue (an important clinical distinction from syncope, the main disorder from which fits must be distinguished, where the face is ashen pale), and is followed by a series of violent, synchronous jerks that gradually die out in 2–4 min. The patient stays unconscious for a few more minutes and then gradually recovers, feeling ill and confused. Injury may occur during the convulsive episode. The EEG shows generalised continuous high-frequency activity in the tonic phase and an intermittent discharge in the clonic phase
Summarise absence seizures
Absence seizures: brief staring episodes with behavioural arrest
Can sometimes lose muscle function too- patient may fall to the ground
Describe absence seizures
Absence seizures occur in children; they are much less dramatic but may occur more frequently (many seizures each day) than tonic–clonic seizures. The patient abruptly ceases whatever he or she was doing, sometimes stopping speaking in mid-sentence, and stares vacantly for a few seconds, with little or no motor disturbance. Patients are unaware of their surroundings and recover abruptly with no after effects. The EEG pattern shows a characteristic rhythmic discharge during the period of the seizure
Summarise tonic/atonic seizures
Tonic/atonic seizures: sudden muscle stiffening/sudden loss of muscle control
Tonic= muscles stiffening Atonic= muscles relaxing
Different type of jerkiness differentiates these from tonic-clonic seizures
Summarise myoclonic seizures
Myoclonic seizures: sudden, brief muscle contractions
What is status epilepticus
Status epilepticus: > 5 min of continuous seizure activity
Can be any one of the other 4 generalised seizures
Most serious and debilitating type of seizure
Requires emergency medical treatment.
Summarise partial/focal seizures
Begins within a particular area of brain and may spread out (to become generalised).
Seizure types & Symptoms
Simple: retained awareness/consciousness
Complex: impaired awareness/consciousness
