12. Epilepsy And Antiepileptic Drugs Flashcards Preview

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Flashcards in 12. Epilepsy And Antiepileptic Drugs Deck (30)
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1
Q

What is a seizure?

A

Transient occurrence of signs or symptoms due to abnormal electrical activity in the brain, leading to disturbance of consciousness, behaviour, emotion, motor function or sensation

2
Q

what can cause an imbalance in inhibitory and excitatory receptors?

A

Genetic differences in brain chemistry/receptor structure (epilepsy)
By exogenous activation of receptors (drugs)
Acquired changes in brain chemistry (drug withdrawal)
Damage to any of these networks (stroke, tumours)

3
Q

What are the signs and symptoms of a seizure?

A

Loss of consciousness with changes in muscle tone, tongue biting
Initial hypertonic phase, followed by rapid clonus of the limbs
Post-ictal period present
Often an aura prior to seizure

4
Q

What can bring on a reflex seizure?

A
Photogenic
Musicogenic
Thinking
Eating
Hot water immersion
Reading
5
Q

What are the 3 types of seizures?

A

Focal onset
Generalised onset
Unknown onset

6
Q

What can cause provoked seizures?

A
Drug use or withdrawal
Alcohol withdrawal
Head trauma and intracranial bleeding
Metabolic disturbances
CNS infections
Febrile seizures in infants
Uncontrolled hypertension
7
Q

What is status epilepticus?

A

A seizure lasting more tan 5 minutes or more, or multiple seizures without a complete recovery between them

8
Q

What are the pharmacological treatment for status epilepticus?

A

0-5mins - full dose of benzodiazepine
0-15mins - 2nd full dose of benzodiazepine
15-45mins - 2nd line antiepileptic (phenytoin/levetiracetam)
45+ mins - thiopentone/anaesthesia

9
Q

What is the class of benzodiazepine?

A

GABAa agonists

10
Q

What is the action of benzodiazepines?

A

Increase Cl- conductance = more negative resting potential, less likely to fire

11
Q

What are the benzodiazepine options for status epilepticus?

A

IV lorazepam
Diazepam rectally
Buccaneers or intranasal midazolam

12
Q

What are the investigations for epilepsy?

A

Electroencephalography

MRI

13
Q

What class of drug is carbamazepine?

A

Sodium channel blockers

14
Q

What are the side effects of carbamazepine?

A

Suicidal thoughts
Joint pain
Bone marrow failure

15
Q

What class of drug is phenytoin?

A

Sodium channel blocker

16
Q

When is phenytoin mainly used?

A

Status epilepticus

Or as an adjunct in generalised seizures

17
Q

What are the side effects of phenytoin?

A

Bone marrow suppression
Hypotension
Arrhythmias

18
Q

What are the actions of sodium valproate?

A

Mix of GABAa effects and sodium channel blockade

19
Q

What are the side effects of sodium valproate?

A

Liver failure
Pancreatitis
Lethargy

20
Q

What is the first line drug for generalised epilepsies?

A

Sodium valproate

21
Q

Where does lamotrigine act?

A

Primarily sodium channel blocker

May also affect calcium channels

22
Q

What is lamotrigine good for?

A

Focal epilepsy

23
Q

What is the action of levetiracetam?

A

Synaptic vesicle glycoprotein binder, stops release of neurotransmitters into synapse and reduces neuronal activity

24
Q

Which antiepileptic drug is safe in pregnancy?

A

Levetiracetam

25
Q

What is levetiracetam used in?

A

Focal seizures and generalise seizures

26
Q

What are some general side effects of AEDs?

A
Tiredness/drowsiness
Nausea and vomiting
Mood changes and suicidal ideation
Osteoporosis 
Rashes - Steven Johnson syndrome
Can cause anaemia, thrombocytopenia or bone marrow failure
27
Q

Which patients need particular monitoring when on AEDs?

A

Those that are also on warfarin

28
Q

Which of the AEDs are CYP enzyme inducers?

A

Phenytoin
Carbamazepine
Barbituates

29
Q

Which of the AEDs is a CYP enzyme inhibitor?

A

Valproate

30
Q

Which AED should not be prescribed to any woman of childbearing age unless on pregnancy prevention programme?

A

Valproate