Epilepsy

Question 1

What investigations are done to diagnose epilepsy?

Answer 1

Clinical hx 
EEG 
MRI 
ECG
Bloods

Question 2

What are some examples of sodium channel blockers used as AEDs?

Answer 2

Sodium valporate
Lamotrigine 
Carbamazepine 
Phenytoin 
Topiramate

Question 3

What is the MOA of sodium channel blockers when used as AED?

Answer 3

Cause Na channels to remain inactive

Prevent axons from firing an AP

Question 4

What are some examples of Ca channel blockers used as AEDs?

Answer 4

Ethosuximide

Sodium valporate

Question 5

What is the MOA of Ca channel blockers used as AEDs?

Answer 5

Prevent activity of Ca channels
Prevent depolarisation

Used in absence seizures

Question 6

What is the MOA of GABA potentiators used in epilepsy?

Answer 6

Enhance effect of GABA at the synaptic junction

Eg barbiturates, benzodiazepines

Question 7

What is the MOA of GABA-transaminase inhibitors used in epilepsy?

Answer 7

Prevent breakdown of GABA

Eg vigabatrin

Question 8

What is the MOA of keppra? (Used for epilepsy)

Answer 8

Binds to synaptic vesicles => inhibit pre-synaptic calcium channel activity
Therefore inhibits release of neurotransmitters

Question 9

When should anti-epileptics be considered?

Answer 9

After a first unprovoked seizure with:
Neurological deficit 
EEG with epileptic activity 
Risk of further seizure is v dangerous (if the pt has a particular job)
Imaging shows a structural abnormality

Question 10

How are AEDs initiated?

Answer 10

Start at lowest effective dose & titrate up

First line for generalised/tonic-clonic : lamotrigine or sodium valporate

Question 11

How can anti-epileptics affect CYP enzymes?

Answer 11

Inducers:
Carbamazepine, phenytoin

Inhibitors:
Sodium valporate

Question 12

What are some adverse effects of all AEDs?

Answer 12

Dizziness
Fatigue
Ataxia
Diplopia

Question 13

How should anti-epileptics be changed?

Answer 13

Need to overlap new drug w/ old drug

Slowly withdraw old drug

Question 14

How should anti-epileptics be stopped?

Answer 14

Gradually taper off
Aim to avoid withdrawal Sx

Consider if pt is seizure free for 2 yrs

Question 15

What are some considerations for use of AEDs in pregnancy?

Answer 15

Risk of congenital malformations

Eg neural tube defects, hypospadias, cardiac defects

Question 16

What congenital defects can result from a pregnant woman taking sodium valporate?

Answer 16

Neural tube defects eg spina bifida
Craniofacial and skeletal abnormalities
Developmental disorders - mental and physical

Question 17

What are some congenital malformations that can result from a pregnant woman taking phenytoin?

Answer 17

Cleft lip and palate

Congenital heart defects - eg septal defects

Question 18

Why does phenytoin require therapeutic drug monitoring?

Answer 18

Narrow therapeutic window

Risk of toxicity:
Nausea, CNS dysfunction, decreased consciousness, coma

Question 19

What drugs are used for the treatment of partial seizures?

Answer 19

Lamotrigine
Phenytoin
Carbamazepine

Gabapentin
Topiramate (also used for migraines)

Question 20

What drugs are used for treatment of general seizures?

Answer 20

Sodium valporate
Ethosuximide
Phenobarbital
Benzodiazepines (status epilepticus)

Question 21

What is the initial management of seizures?

Answer 21

Midazolam or lorazepam

Question 22

What is the treatment for status epilepticus?

Answer 22

Phenytoin of benzodiazepines