16 EPILESPSY

Question 1

Define epilepsy

Answer 1

Recurrent, unprovoked epileptic seizures which comprise of abnormal electrical discharges from neurons in cerebral cortex

Question 2

What is a convulsive syncope

Answer 2

Collapse and convulsions due to reduced perfusion to the brain

Question 3

How does seizure activity spread through the brain

Answer 3

Via synaptic pathways and gap junctions to adjacent neurons

Question 4

What percentage of the population have epilepsy

Answer 4

0.5-1%

Question 5

Describe focal vs. generalised

Answer 5

Focal- part of the brain

Generalized- involves both hemispheres

Question 6

What is a seizure called that is focal and there is LOC

Answer 6

Complex partial/ focal with loss of awareness

Question 7

Subtypes of generalised seizure

Answer 7

Tonic (pt goes stiff)
Clonic (involuntary rhythmic muscle contractions) 
Tonic/clonic
Myoclonic (sudden startle)
Atonic 
Absence seizure

Question 8

What are the two major types of non NMDA receptors

Answer 8

AMPA and kainate

Question 9

What is glutamate receptor is blocked with Mg2+

Answer 9

NMDA

Question 10

What ion channels have allosteric binding sites for benzodiazepines and barbiturates

Answer 10

GABA receptors (Cl- ion channels, hyperpolarize the membrane)

Question 11

Discuss the plasticity of ion channels

Answer 11

Channels have substantial plasticity. Excitatory channels are potentiated when fired repetitively. NMDA receptors important in long term potentiation. Important in memory. Maybe important in generating seizures

Question 12

Mutations in which channels cause the worst kind of epilepsy

Answer 12

Na+ channels. E.g. severe myoclonic epilepsy of infancy, generalised epilepsy with febrile seizures

Question 13

Two drugs that induce seizures and how

Answer 13

Antagonist at GABA receptors.
Bicuculline.
Penicillin

Question 14

Name four mechanisms of action of anti seizure drugs

Answer 14

=Na+ channel blockers (pre-synaptic)
=Enhancement of GABA transmission
=Ca2+ channels
=Glutamate antagonist

Question 15

Name two Na+ channel blockers

Answer 15

Carbamazepine
Phenytoin
SV

Question 16

Name two GABA transmission enhancers

Answer 16

Vigabatrin
Benzodiazapines (emergency use)
Barbituates

Question 17

Name two glutamate blocking agents

Answer 17

Topirimate

Lamotrigine

Question 18

Discuss autoantibody induced epilepsy syndrome

Answer 18

=Body produces antibodies against ion channels.
=Causes epilepsy in people previously well
=Causes severe forms of epilepsy associated with encephalitis and memory disturbance
=Mainly temporal lobe channels

Question 19

Describe the concept of kindling

Answer 19

Whereby seizures beget seizures.

Question 20

Where does neuron death typical occur in repeated seizure activity and consequences of this

Answer 20

Temporal lobe, memory loss.