Seizures and Epilepsy

Question 1

Define seizure

Answer 1

temporary, unstoppable surge of electrical activity within the brain where affected brain cells uncontrollably fire signals to others around them impacting their function also

Question 2

compare prevalence of seizures to epilepsy

Answer 2

11% of people will have a seizure whereas approx 1% of Australians diagnosed with epilepsy

Question 3

describe epilepsy

Answer 3

hypersynchronous hyperexcitability of groups of neurons starting from a focus, membrane potential of these cells may be more depolarised than usual

Question 4

list the factors of predisposition for epilepsy

Answer 4

genetic susceptibility or chronic pathologic process

Question 5

compare the different classifications of epilepsy

Answer 5

generalised: involves both cerebral hemispheres, tonic, clonic and absence
partial: simultaneous firing of group of neurons, often caused by focal trauma, simple or complex

Question 6

compare the tonic, clonic and postictal phases of a seizure

Answer 6

tonic: contraction of whole body musculature, cry/groan, LOC, resps stop, salivation
clonic: violent, synchronous jerks
postictal stupor: unresponsive, salivating, drooling, limp, disorientated

Question 7

List the symptoms of an absence seizure

Answer 7

staring and fluttering eyes, often have no recollection of what happened

Question 8

What factor determines the symptoms of a partial seizure?

Answer 8

the site of pathological discharge of the firing neurons

Question 9

compare simple and complex partial seizures

Answer 9

simple: remain conscious, preserved awareness
complex: LOC, unpreserved awareness, temporal lobe

Question 10

list the causes of partial seizures

Answer 10

infection, trauma, drug abuse, lack of sleep, flashing lights, tumour

Question 11

define status epilepticus

Answer 11

one seizure lasting >30mns or 2 or more sequential without full recovery of consciousness, life threatening 30% of the time

Question 12

list the 4 targets of pharmacology treatment for epilepsy

Answer 12

blocking sodium channels, blockade of presynaptic calcium channels, strengthening of GABAergic input, blockade of Gluergic input

Question 13

Describe MOA of antiseizure meds targeting blockade of sodium ion channels

Answer 13

they bind preferentially to inactivates state of channel and inhibit rapid firing, selectively block ions moving through channel

Question 14

Describe MOA of antiseizure meds targeting blockade of presynaptic calcium channels

Answer 14

reduce NT release and slow synaptic function

Question 15

Describe MOA of antiseizure meds targeting increase of GABAergic transmission

Answer 15

positive allosteric modulators of GABA receptors increase reduction of membrane potential and APs

Question 16

Describe MOA of antiseizure meds targeting reduction of Glu activity

Answer 16

block excitatory activity and APs by blocking Glu Rs receptors

Question 17

List the pharmacodynamic properties of anti-epilepsy drugs

Answer 17

narrow therapeutic index, patients may experience CNS depression, hypersensitivity manifested through skin reactions, teratogenicity (pregnancy risks v benefits)

Question 18

List the pharmacokinetic properties of anti-epileptic meds

Answer 18

long half life >12hrs, modulation of CYP enzyme, poor patient compliance, TDM recommended