Epilepsy

Question 1

Epilepsy defintion Causes is a tendency to?

Answer 1

Abnormal, excessive electrical discharge from neurones. Imbalance between excitation and inhibition. Often associated with a loss of consciousness Causes include genetic, structural or metabolic/functional have recurrent seizures

Question 2

What causes seizures? note alterations of ion channels

Answer 2

Occur as a result of abnormal synchronous activation of many hyperexcitable neurons. Can spread through synaptic and non synaptic pathways

Question 3

What are the classifications of epileptic seizures? Note a seizure can start focally and end generalised

Answer 3

Focal: Manifestations depend on which part of the brain is affected. Conscioiusness is preserved in simple ones. Generalised: manifestations vary greatly, loss of responsiveness: With or without motor manifestations

Question 4

Tonic, clonic and myoclonic seizures. Occur usually with what seizure type?

Answer 4

Tonic: sustained contraction of axial and limb muscles Clonic: Regular repeated tonic contractions Myoclonic: sudden brief jerks Generalised.

Question 5

What can be said about loss of consciousness?

Answer 5

Not always a product of a epileptic seizure. May also be a result from other pathological processes.

Question 6

What are the types of glutamate transmitters? EXCITATORY

Answer 6

NMDA and non NMDA receptors

Question 7

NMDA vs non NMDA recpetors

Answer 7

NMDA: Slow to activate, selective for calcium. Magnesium blocks channel when fully polarised, and is expelled when partially depolarised, to continue depol. non NMDA: Rapidly inactivate and activate, allow cations through, not really calcium

Question 8

GABA receptor INHIBITORY

Answer 8

Receptor binds two GABA, will open and allow CL- in to hyperpolarise cell. Benzodiazepines and barbiturates can bind to these

Question 9

Mutations in ion channels

Answer 9

K+: In children can have seizures. Not always lasting Na+: bad in type 1 channel mutations e.g Dravets Syndrome,

Question 10

Absence seizure generalised?

Answer 10

Brief loss and gain of consciousness can be clonic, atonic etc

Question 11

What drugs will induce seizures? (3 types)

Answer 11

Block GABA: penicillin Glu activators: low Mg2+, kainate, domoic acid Block K+ voltage 4-aminopyridine (MS?)

Question 12

Drugs to treat seizures types and examples

Answer 12

Na+ channel blockers: carbamazepine and phenytoin. Prevent sustained repetitive firing Enhancement of GABA transmission: diazepans and barbiturates. vigabatrin Calcium channels: Glutamate block:

Question 13

Autoantibody induced epilepsy

Answer 13

Anti potassium channels - epilepsy and encephalitis Anti NMDA channels

Question 14

What is the kindling effect of seizures?

Answer 14

The fact that one seizure means that subsequent seizures are more likely. Unsure in humans

Question 15

Effects of seizures

Answer 15

Rearrangement of local neuronal circuits and loss of neurons. e.g temporal lobe epilepsy causing memory loss