Epilepsy Flashcards
What are the 3 phases of an epileptic seizure?
- Prodromal (aura)
- Ictal (seizure)
- Post-ictal (recovery)
What are the types of epileptic seizures?
- Generalized
- primary
- secondary - Focal
- complex partial
What are generalized seizures caused by?
Abnormal oscillations in thalamocortical loops
What is a secondary generalized seizure?
Where a partial seizure spreads to involve both cerebral hemispheres
Complex partial seizures commonly originate in which lobe?
Temporal lobe
Which type of seizure is frequently preceded by an aura?
Complex partial seizure
On an EEG, what type of waves would be seen if someone was awake + alert?
Beta waves
On an EEG, what type of waves would be seen if someone was awake + relaxed?
Alpha waves
On an EEG, what type of waves would be seen if someone was in a coma?
Delta waves
Focal seizures originating in the temporal lobe often cause which automatisms?
Chewing, lip-smacking
What are the 2 types of Jacksonian seizures?
Focal aware motor
Focal aware sensory
In what direction do Jacksonian seizures travel?
Distal to proximal
In a primary generalized tonic-clonic seizure, how long does the tonic stage last?
10 - 40 seconds
In a primary generalized tonic-clonic seizure, how long does the clonic stage last?
2 - 3 minutes
In relation to seizures, what is meant by ‘tonic’?
Muscle rigidity
In relation to seizures, what is meant by ‘clonic’?
Repetitive muscle contractions
Absence seizures generally occur in what age group?
Childhood
What will the EEG pattern be for an absence seizure?
Spike-and-wave patterns
Which epileptic situation is a medical emergency?
Status epilepticus
For how long does a seizure need to last to be considered status epilepticus?
> 5 minutes
What is the mortality rate of status epilepticus?
10 - 15%
What 3 things can status epilepticus result in?
Brain hypoxia
Brain acidosis
Excitotoxicity
What is excitotoxicity?
Cell death caused by the excessive release of glutamate
What is the electrical basis for the initiation of a focal seizure?
Paroxysmal depolarising shift (PDS)
Which 2 ion channels and receptors are involved in the depolarisation phase of a paroxysmal depolarising shift (PDS)?
Na channels
Ca channels
AMPA glutamate receptors
NMDA glutamate receptors
What prevents a paroxysmal depolarising shift (PDS) / focal seizure from spreading?
Inhibitory interneurons around the focus providing a surround inhibition via GABA synapses
What is the most common pathological finding in focal epilepsy?
Hippocampal sclerosis
Hippocampal sclerosis involves neuronal loss in which area of the hippocampus?
CA1 subfield
What is the most common type of hippocampal sclerosis?
Mesial temporal sclerosis
Mesial temporal sclerosis involves the loss of which type of cells?
Hilar cells
Loss of hilar cells in mesial temporal sclerosis can lead to what? Why does this increase seizure activity?
Mossy fibre sprouting
New mossy fibre connections are not inhibited by the normal inhibitory connections. New connections may be self-excitatory and promote seizure activity
Which condition that affects the cortex can cause epilepsy?
Focal cortical dysplasia
Which 3 types of cell are found in focal cortical dysplasia?
Balloon cells
Dysplastic neurons
Giant neurons
Spike-and-wave patterns on an EEG are a sign of which type of seizure?
Absence seizure
Which cells have been implicated in the initiation of PDS’s?
Astrocytes
What are 3 non-pharmacological treatments of epilepsy?
Surgery
Nerve stimulation
Ketogenic diet
In nerve stimulation for the treatment of epilepsy, which nerve is stimulated and by how much does it reduce seizure frequency?
Vagus nerve - reduces seizure frequency by 50%
The effects of which type of seizure travel distal to proximal?
Jacksonian
