11.1 - Epilepsy and AEDs Flashcards

1
Q

what are the 2 types of generalised seizures?

A

absence and tonic-clonic

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2
Q

What occurs in an absence seizure?

A

staring, eyelid twitching, few muscle jerks. normal activity post attack

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3
Q

What occurs in a tonic-clonic seizure?

A

2 phases:

1) Tonic phase - body rigid, patient falls to floor, incontinence
2) clonic phase - convulsions, frothing at mouth, jerking of muscles

Followed by drowsiness, confusion or coma for several hours

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4
Q

What are the 2 types of partial seizures? What occurs in each of them?

A

Simple - conscious seizure

Complex - impaired consciousness, can become generalised

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5
Q

Define epilepsy

A

Tendency towards recurrent seizures

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6
Q

Define status epilepticus

A

Single convulsion lasting >30mins or convulsions ocurring back to back with no recovery

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7
Q

How can status epilepticus cause damage?

A

Physical injury due to fall, hypoxia, SUDEP

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8
Q

How can epilepsy be classified?

A

Primary - idiopathic

Secondary - known cause

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9
Q

What are some underlying causes which can result in epilepsy?

A

Brain tumours, pyrexia, alcohol or drugs or withdrawal, brain tumours, hypoglycaemia, brain injury

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10
Q

How would you take a history of a seizure?

A

Witness statements, pre, peri, and post seizure

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11
Q

What are the 4 types of AEDs?

A

Inhibition of glutamate release, inhibition of Ca channel, Inhibtion of Na channel, enhancement of GABA(A) action

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12
Q

What are the 3 types of inhibitiors of na channels?>

A

Lamotrigine, phenytoin, carbamezepine

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13
Q

What is the MoA of inhibitors of Na channels?

A

Only binds to channels in inactive state, preventing channels from returning to a resting state where they could continue to depolarise neurons. Preferentially binds high frequency discharge neurons

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14
Q

What are some ADRs of carbamezepine?

A

N&V, rashes, myelosuppression, dizziness, parasthesia, teratogenic

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15
Q

What are some ADRs of phenytoin?

A

Gingival hyperplasia, heaches, nystagmus, dizziness, hypersensitivity rashes, teratogenic

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16
Q

What are some ADRs of lamotrigine?

A

dizziness, ataxia, nausea, rashes,

17
Q

What are the DDIs of the inhibitors of Na channels?

A

Phenytoin and carbamezepine - inducers of CYP450

Lamotrigine - oral contraceptives

18
Q

What are the 2 types of enhancers of GABA action?

A

Valproate sodium, BZDs

19
Q

Why is phenytoin used in emergency treatment?

A

Zero order kinetics - quickly reaches therapeutic levels

20
Q

What is the MoA of valproate sodium?

A

Stimulates GABA synthesis and inhibits GABA inactivation

21
Q

What is the MoA of BZDs

A

Positive allosteric modulation of GABARs.

22
Q

Give an example BZD

A

lorazepam

23
Q

What are some ADRs of valproate sodium?

A

ataxia, tremor, N&V, sedation, teratogenic

24
Q

What are some ADRs of BZDs?

A

sedation, tolerance, confusion, aggresssion, resp and CNS depression, teratogenic

25
Q

How would you prescribe an AED? What rules would you folow

A

aim for monotherapy, start low and increase dose to maximise effect and minimse ADRs

26
Q

What AED would you use for primary generalised seizures?

A

Valproate sodium or lamotrogine

27
Q

What AED would you use for partial seizures?

A

Carbamezepine or lamotrigine

28
Q

What AED would you use for Status epilepticus?

A

BZD and IV phenytoin

29
Q

What AED would you use in pregnancy and why? What other supplements would you combine it with?

A

Use lamotrigine - reduced teratogenic effects
Combined with folate and vit K supplements. Vit K reduces risk of cerebral hemorrhage and coagulopathy associated with AED-linked vit K deficiency. Folate reduces risk of neural tube defects

30
Q

What would you do in an emergency involving status epilepticus?

A

1) ABC
2) lorazepam and then IV phenytoin
3) treat underlying cause
4) if all else fails, ITU referral with paralysis, sedation and intubation

31
Q

Give some secondary causes of epilepsy

A

alcohol, drugs, withdrawal, flashing lights, pyrexia, brain tumours