Epilepsy

Question 1

Define the term seizure

Answer 1

Clinical manifestation of a disordered and hypersynchronised discharge in a network of cerebral neurones

Question 2

How are seizure types determined?

Answer 2

Location of onset, type of discharge and spread pattern

Question 3

Differentiate between generalised and focal seizures

Answer 3

Generalised starts simultaneously in both hemispheres

Focal- starts in a focus then spreads

Question 4

Name three types of generalised seizures

Answer 4

Absence
Myoclonic
Tonic clonic

Question 5

Describe absence seizures

Answer 5

Childhood onset
Short lived
Frequent attacks- 100s per day
No aura/post ictal state, some involuntary movements
Brought on by hyperventilation

Question 6

Describe myoclonic seizures

Answer 6

Sudden, brief, shock like muscle contractions, bilateral
Worse in mornings, precipitated by sleep and alcohol
Also non epileptic cause- CTD. Epileptic- juvenile myoclonic epilepsy

Question 7

Describe tonic clonic seizures

Answer 7

Sudden onset, gasp, fall
Tonic phase- cyanosis, stiff, rapid movements, bite tongue, insomnia
Clonic phase- build up of rhythmic activity
Post ictal phase- confusion, headache, muscle pain

Question 8

Describe atonic seizures

Answer 8

Rare, affects young kids, sudden loss of muscle tone, occurs without warning- fall

Question 9

Describe focal seizures

Answer 9

Have AURA- pre warning- visual, olfactory, taste, movement
Simple partial- awareness, complex- loss of awareness and automatisms in vol movements
Secondary generalised- tonic clonic (head turns), posturisation, vocalisation

Question 10

Frontal lobe focal seizures

Answer 10

Mild vocalisation, posturing of arms and legs. Rapid recovery- no post ictal state

Question 11

Temporal lobe

Answer 11

Aura/epigastric rising sensation.
Olfactory, gustatory, deja vu
Complex partial- arrest reaction and blank stare. Oral automatisms, lip smacking
Recovery not immediate but presence of non responsive post ictal state
May see propagation from temporal to frontal

Question 12

Describe the use of sodium channel blockers in epilepsy

Answer 12

Some epilepsies caused by gain of function mutations in Na channels– increased persistent current- hyperexcitable
Drugs prolong inactivated site
block repetitive activation, reduces burst firing

Question 13

Describe the use of Sodium Valproate

Answer 13

Uncertain action
GABA, inhibits excitatory transmission through Ca, K
1st line for partial and generalised
POWERFUL against myoclonus, absence and photosensitive
Teratogenic effects in young women

Question 14

Lamotrigine

Answer 14

First line in generalised and focal
Low side effects- rash
Useful in myoclonus, absence
Well tolerated
Serum levels decrease when combined with oral contraceptives and pregnancy

Question 15

Carbamezapine

Answer 15

Acts on sodium channels, suppresses burst activity and spread of seizures
partial and generalised seizures
Not good for myoclonus and absences
Relatively well tolerated but shows interactions due to enzyme induction.

Question 16

Phenytoin

Answer 16

Acts on sodium channels to suppress burst activity and spread
2nd line for partial and generalised
Variable absorption due to rate-limiting para-hydroxylation and high protein binding – some co-medications both induce enzyme and inhibit enzyme activity…
Metabolism varies with age