Epilepsy Flashcards by Nicola Fay

What two types of seizures can we get?

generalised - both hemispheres

focal - starts in on hemisphere but can move into the other

How well did you know this?

Not at all

Perfectly

Provoked seizures in patients who do not have epilepsy may be caused by

alcohol or drug withdrawal
fever
hypoxia
hypoglycaemia

How well did you know this?

Not at all

Perfectly

Different ways in which drugs can cause seizures

lowering the seizure threshold e.g. cipro, tramadol
drug interaction reducing anti-epileptic drug levels (e.g. hepatic microsomal enzyme induction with rifampicin)
effects secondary to other medical causes (e.g drug induced hyponatraemia)
individual anti-epileptic drugs which may themselves cause worsening of some seizure types.
drug withdrawal (e.g. illicit, alcohol, benzodiazepine, baclofen)

How well did you know this?

Not at all

Perfectly

Diagnosis of epilepsy

two unprovoked seizures more than 24 hours apart
one unprovoked seizure with a high risk of another
diagnosis of epilepsy syndrome
ECG, EEG, neuroimagine

differential diagnosis - non-epileptic attack disorders (pseudo seizures) Characterised by a change in behaviour or movement but unlike epilepsy are not caused by primary change in electrical activity of the brain. More prevent in females and early onset in adolescence.

How well did you know this?

Not at all

Perfectly

When is it appropriate to take phenytoin levels?

Adjusting phenytoin doses
Assessing adherence to therapy
Identifying potential treatment toxicity
Assessing potential changes to drug metabolism e.g. pregnancy, drug-drug interactions
unexplained loss of seizure control

How well did you know this?

Not at all

Perfectly

What bloods should be monitored when using sodium valproate?

LFT’s. Can cause hepatic dysfunction.

How well did you know this?

Not at all

Perfectly

How do we load phenytoin naive patients?

20mg/kg IV

capped at 2gram

How well did you know this?

Not at all

Perfectly

What is the phenytoin salt factor (for caps and injection)

0.92

How well did you know this?

Not at all

Perfectly

What is the phenytoin volume of distribution?

0.65L/kg

How well did you know this?

Not at all

Perfectly

What is usually the initial maintenance dose for phenytoin?

3-4mg/kg/day

How well did you know this?

Not at all

Perfectly

What is a clinically effective serum phenytoin concentration?

10-20

How well did you know this?

Not at all

Perfectly

Phenytoin levels

Total serum phenytoin levels reflect both free and unbound drug. Only the free fraction of phenytoin is active and in healthy adults around 90% of phenytoin is bound therefore levels have to be adjusted in patients with low albumin.

How well did you know this?

Not at all

Perfectly

What is the corrected phenytoin level equation for patients with low albumin but normal renal function

observed phen level/(0.9x(albumin g/dL/44)) + 0.1

How well did you know this?

Not at all

Perfectly

What is the usual dose increments we see with phenytoin?

25-50mg max

How well did you know this?

Not at all

Perfectly

what do women of child baring age have to sign up to if they’re on sod val

PPP

How well did you know this?

Not at all

Perfectly

what sort of contraception do we recommend in epileptic patients who are taking enzyme inducing anti epileptics?

COC with at least 50microgram os oestrogen

POC and rings/implants/patch are not recommended

How well did you know this?

Not at all

Perfectly

What are enzyme inducing anti-epileptics?

Esilcarbamazepine
carbamazepine
oxcarbamazepine
perampanel (12mg/day)
phenobarbital
phenytoin
primidone
rufinamaide
topiramate (>200mg/day)

What contraception can women take who are taking non-enzyme inducing anti epileptics?

They can take anything.

Lamotrigine is a none enzyme inducing drug however it does interact with some contraceptions.

Lamotrigine clearance is doubles by ethinyloestrodiol/levonorgestrel 30mcg/150mcg, threatening seizure control, lamotrigine dose may need to be increased.

Desogestrel may increase lamotrigine concentrations.

Advice for emergency contraception?

single dose of levonorgestrel 3mg as soon as possible within 72 hours of unprotected intercourse.
ulipristal acetate is not recommended due to reduced efficacy
insertion of non-hormonal intra-uterine device within 5 days of intercourse is effective

What emergency hormonal contraception is not recommended?

ulipristal acetate due to reduced efficacy

When could patients think about surgery?

Patients who have focal seizures who are on two medicines at adequate doses for two years without a substantial response.

VNS and DBS

vagus nerve stimulator
deep brain stimulator

Supply mild electrical impulses. If the patient feels an aura then they can press a button which send impulse to the right place.

What is status epileptics defines as?

seizure > 30 minutes whether it is a prolonged seizure or repeated seizures with no recovery in-between.

duration of tonic-clonic seizure which should then be treated as a medical emergency

5 minutes

what can long term status epileptics cause?

- respiratory compromise - cardiorespiratory arrest - if left untreated - permanent cerebral damage

timings of seizures

5 mins is the earliest point at which we ca treat 30 mins indicates a risk at which long term damage can occur

What is first line treatment for status epilepticus

Benzodiazepines: community - buccal midazolam or rectal diazepam hosp - IV lorazepam favoured. An anti epileptic should be started irrespective of whether a patient is convulsing or not as when the benzo wears off we don't want rebound seizures. - Phenytoin is first line - Fosphenytoin may be given if poor IV access. It is a prodrug of phenytoin and can be given IM. - Historically if this persists then phenobarbital can be given but is rarely used as it can cause respiratory and CNS depression

Does carbamazepine induce its own metabolism?

Yes therefore it should be gradually increased every two weeks.

Points taken from the SANAD trial READ!!!

- gabapentin was found to be more likely than other convulsants to be associated with treatment failure in the management of focal epilepsy - lamotrigine is the drug of choice in focal epilepsy - valproate is the drug of choice in generalised and unclassified epilepsy - rash was more commonly reported for patients on carbamazepine than lamotragine

Shall we take sodium valproate levels to ensure it is therapeutic?

NO!!

Give examples when it is appropriate to do TDM

- assess the adherence of sodium valproate therapy - unexplained status epileptics in a patient taking lamotragine - To ensure phenytoin levels are therapeutic - suspected carbamazepine toxicity

Are women at higher risk of seizing when they are pregnant?

No they are generally unlikely to have a seizure in pregnancy and a few months after birth

Are lamotrigine levels increased or decreased by oestrogen containing contraceptives?

They are DECREASED. As clearance of the drug doubles so we may have to increase the dose.

Facts about contraception

- The progesterone only pill is not recommended as a reliable contraception in women taken enzyme inducing anti epileptics - The dose of levonorgestrel required for emergency contraception in women taking enzyme inducing drugs is 3mg. - Desogestrel may increase lamotrigine concentration - insertion of non-hormonalinteruterine device within 5 days of intercourse is an effective method of emergency contraception regardless of AED therapy.

SUDEP

there is an apparently increase in SUDEP in people with frequent daytime seizures.

a medicine which can reduce the seizure threshold is

baclofen

Is carbamazepine excreted by the kidney and should it be avoided in renal impairment?

What epileptic drug cause PR interval prolongation?

Lacosamide

Which antiepileptic can cause progressive visual loss

Vigabatran

Which antiepileptic causes urilothiasis

Topiramate

Which antiepileptic causes SJS

Lamotrigine and carbamazepine

Best antidepressant in epilepsy

They can all lower the seizures threshold Best is SSRI sertraline CI in patient s with poorly controlled epilepsy