Epilepsy Flashcards
(25 cards)
Definition of a seizure
A convulsion caused by paroxysmal discharge of cerebral neurones
Definition of epilepsy
Neurological disorder characterized by recurrent sudden onset seizures
Types of focal seizures
Focal aware (simple) Focal impaired awareness (complex)
Focal to bilateral tonic-clonic seizure is where
Seizure begins in an area in one hemisphere of the brain but spreads to involve both hemispheres
Tonic seizure
All muscles become stiff
May lose balance and fall (usually back)
Clonic seizure
Body jerks (more regular & sustained than myoclonic)
Usually lasts a few minutes
May lose consciousness
Patient usually falls backwards in this type of seizure
clonic
Patient usually falls forwards in this type of seizure
atonic
Myoclonic seizure
Some/all of body suddenly jerks and twitches like you’ve had an electric shock
Atonic seizure
All your muscles relax (loss of tone) suddenly May fall (usually forwards)
Causes of epilepsy
2/3 idiopathic Other causes: Head injury Disease - tumour, infection Stroke Ischemia during birth
The most common type of epilepsy in adults which happens to have the most complex presentation
Temporal lobe epilepsy
Presentation includes: abdominal pain, de ja vu, delusional behaviour, complex motor phenomena
Focal aware seizures
Can cause: stiffness or twitching in part of the body eg hand, arm tingling strange smells, tastes deja vu Remain awake and aware
Focal impaired awareness seizures
Lose your sense of awareness and make random movements such as:
lip-smacking, moving arms around, chewing/swallowing, rubbing hands
Status epilepticus is
A seizure that lasts a long time or series of seizures between which the patient does not re-gain consciousness
What makes seizures so dangerous
Patient can stop breathing or ventilate very little during making them potentially fatal
What is happening in the brain during an epileptic seizure
Sudden excessive, synchronous, high frequency neuronal discharge in the cerebral cortex
Dormant basket cell hypothesis of epilepsy
GABAergic inhibitory interneurones are dormant as they lose excitatory input > so they are not excited to inhibit pyramidal cells via GABA
Fundamentally, what is the pathology of epilepsy?
Excitatory/inhibitory balance is lost
A loss of GABAergic inhibition of pyramidal cells
An increase in glutamatergic excitation of pyramidal cells
A hallmark of epilepsy - axonal sprouting
Some of the cells providing afferent excitation to pyramidal cells are lost so pyramidal cells do axonal sprouting in response. Cells connect in an abberant way and create a dense extensive network so that much more glutamate is released - balance is shifted in favour of excitation.
Tonic-clonic seizure
Tonic phase - body goes stiff & person may fell
Clonic phase - body jerks and twitches, may lose control or bladder/bowel, bite tongue, breathing may be difficult
How is epilepsy diagnosed
Look at pre-ictal, ictal, post-ictal symptoms
Bystander account helpful
MRI & EEG
What is an aura
Part of the seizure that the patient is aware of, preceding other manifestations. Usually suggests focal seizures. Could be a strange feeling, smell etc
When is surgery appropriate in epilepsy?
Resistant to multiple AEDs and has a single epileptogenic focus in brain