Epilepsy Flashcards
What are tonic-clonic convulsions?
Previously known as grand Mal
Often without warning
Involves loss of consciousness with a full fit
What is an absence seizure?
Previously known as petit Mal
Often in children
Often patient goes blank, staring for 10 seconds
What are myoclonic seizures?
Abrupt, shock-like jerks
May affect whole body, arms or legs
Which other pathologies/causes which may present as seizures need to be excluded?
Cerebral tumour Cerebrovascular accident Alcohol withdrawal Hyper/hypoglycaemia Syphilis Drugs (antidepressants may reduce seizure threshold)
What is the management for generalised seizures?
1st line valproate or carbamazepine or lamotrigine (in females of child bearing age)
2nd line levetiracetam
What is the management for absence seizures?
1st line ethosuximide
2nd line valproate/lamotrigine
What is valproate?
Potentiates GABA Causes Na-channel blocker Side effects: sedation, weight gain, tremor Causes birth defects Causes liver damage
What is carbamazepine?
Use dependent blockade of Na channels
Side effects: rashes, dizziness, double vision
Many interactions: induction leads to accelerated metabolism of interacting drugs
Causes birth defects
What is phenytoin?
Less commonly used
Side effects: increased gum growth, nystagmus (toxic effect)
Causes birth defects
What is the zero order kinetics of phenytoin?
Metabolism saturates and so get disproportionate increases in plasma concentration of increasing dose
Rates of metabolism varies between patients
Requires plasma concentration monitoring
What is lamotrigine?
Use dependent blockade of Na-channels, reduces release of glutamate
Not particularly sedating
Withdraw if the patient develops rash/flu-like illness- risk of bone marrow toxicity
What are the haematological effects of anti-epileptic drugs?
Can cause leucopenia (fever, sore throat, rash, mouth ulcers)
Withdraw if severe leucopenia
Lamotrigine0 aplastic anaemia
Valproate- thrombocytopenia
How do anti-epileptic drugs affect the liver?
Carbamazepine and valproate affect hepatic function
LFT (essential with valproate) and INR monitoring
How do anti-epileptic drugs affect the skin?
May cause rashes
Stevens-johnson syndrome, toxic epidermal necrolysis (carbamazepine, lamotrigine, phenytoin, valproate)
How do you treat epilepsy in pregnancy?
Withdraw if possible before conception
Treatment is preferable to hypoxic seizures
Reduced control of epilepsy (due to enzyme induction and increased volume of distribution)
Which anti-epileptic are teratogenic?
Carbamazepine, valproate, phenytoin
Neural tube defect
Carbamazepine has been favoured, lower rate of birth defect
How is a neural tube defect prevented?
5mg folic acid daily in trimester 1, counselling and screening
Why can neonatal bleeding tendency be increased?
Carbamazepine and phenytoin (enzyme induction)
Vitamin K1 given for third trimester
What can lead to failure of oral contraceptives?
Enzyme induction with phenytoin, carbamazepine and phenobarbitone
What is considered first line is pregnancy?
Lamotrigine for generalised seizures
What is status epileptics?
Continuous seizure for 30 mins or 2 fits without recovery between them
What is used to treat status epilepticus?
Lorazempam i.v Diazepam i.v or rectal solution Clonazepam Phenytoin slow i.v Failing above general anaesthetic like propofol
When are epileptic patients allowed to drive?
Seizure free for 1 year
Or if attacks occur while asleep over a 3 year period
some drugs cause drowsiness, avoid driving
When is withdrawal considered in epilepsy?
Patient is seizure free for 2-4 years
Withdrawal gradually as this can precipitate epilepsy
Reduce dose every 4 weeks
Stop driving during withdrawal
