Epilepsy

Question 1

Describe the different types of seizures? Describe the aim of treatment?

Answer 1

Tonic-clonic: Full loss of conciousness and fit with a post ictal phase

Absent: Patient goes blank for 10 seconds
Very uncommon in adults

Myoclonic: Abrupt, shock-like jerks. May affect whole body, arms or legs.

It is important to 1st rule out other causes of seizure:
SOL, cerebrovascular event, alcohol withdrawal, hyper/hypoglycaemia, syphilis.

The aim of treatment is the control seizures with lowest possible dose with fewest side-effects.

Question 2

Describe the drug management of epilepsy?

Answer 2

Monotherapy is preferred and the treatment is built up slowly.

Generalised seizures:
1st choice valproate or carbamazepine or lamotrigine (in females of childbearing age)
2nd levetiracetam

Question 3

Describe the mechanism of action of Valporate and the important prescribing points?

Answer 3

Potentiates GABA and causes a Na channel blockade.

S/e: sedation, wt gain and a tremor.
May cause thrombocytopenia.

It is teratogenic and causes limb abnormalaties.

Question 4

Describe the mechanism of action of carbamezapine and the important prescribing points?

Answer 4

Use-dependent blockade of Na-channels

Side effects:
Rashes
Dizziness
Double vision

CyP450 inducer.

Increased incidence of neural tube defects but preferable to valporate and phenytoin. Add additional folate supplementation.

Question 5

Describe the mechanism of action of lamotrogine and the important prescribing points?

Answer 5

Use dependent blockage of Na channels and reduces the release of glutamate.*

Can be used in pregnancy.

It is not sedating but can cause bone marrrow toxicity and therefore if patient must be councelled to come in if they get any flu like symptoms.

Question 6

Describe the reasons phenytoin is rarely used long term?

Answer 6

Many side effects
increased gum growth
nystagmus a toxic effect
parkonsonisms

CyP450 inducer

Teratogenic

Zero order kinetics (metabolism becomes saturated so a small increase may have a disproportionate affect)

Question 7

Describe the important monitoring needed for anti-epileptics?

Answer 7

FBC: many can cause leucopenia
Lamotrigine – associated with aplastic anaemia
Valproate – may cause thrombocytopenia

LFT’s:
Carbamazepine and valporate can both alter hepatic function.

All can cause steven johnson’s syndrome so be aware of this.

Question 8

Describe the treatment of someone in status epilepticus?

Answer 8

Only treat if fit is lasting >5mins.

In community: Rectal diazepam

In hospital: IV lorazepam/diazepam/clonazepam

Or Phenytoin iv slow release

Or failing the above the general anaesthetic propofol