Epilepsy Flashcards
What is epilepsy? Describe what happens in neurons during a seizure
Epilepsy is diagnosed when a patient suffers repeated epileptic seizures. Seizures are sudden episodes of abnormal bursts of excitatory brain activity, leading to transient motor, autonomic, psychic, or sensory dysfunction.
List 3 possible causes of epilepsy?
Inherited component
Non-structural metabolic causes e.g. related to alcohol abuse or hypoglycaemia.
Physical damage to part of the brain e.g. caused by trauma, ischaemia (brain cell death due to inadequate oxygen supply as in stroke) or tumours
List the major seizure categories including 2 types of seizures from each
Focal/ Partial seizures
Generalised seizures: Tonic-clonic Absence Myoclonic Atonic and Tonic
Status epilepticus
What is the main aim of treatment in epilepsy?
Prevent the occurrence of seizures while minimising unwanted effects. Maximise quality of life
List the 3 primary mechanisms of action of antiepileptic drugs
- Decreased sustained high frequency firing of action potentials
e. g. carbamazepine, gabapentin, lamotrigine, phenytoin, topiramate, and possibily sodium valproate - Increases GABA influence
- Blockage of the T-type Ca2+ channels
e. g. Ethosuximide
What should be considered when deciding on treatment? (5)
Seizure type Age Sex Concomitant medicines Co-morbidity
Give some examples of anti-epileptics with a long half life?
Lamotrigine
Perampanel
Phenytoin
Phenobarbital
How do you change from one drug to another?
Slowly withdrawing first line treatment once new regime is established
MHRA (2013) - maintaining patients on the same brand. Medicines are categorised into 3 groups. Which ones are included in each?
Category 1: ensure same brand Phenytoin Carbamazepine Phenobarbital Primidone
Category 2: based on clinical judgement if need to keep on same brand Valproate Lamotrigine Perampanel Rufinamide Clobazam Clonazepam Oxacarbazepine Eslicarbazepine Zonisamide Topiramate
Category 3: unnecessary to keep same brand unless there is concern e.g. patient anxiety, risk of dosing errors Levetiracetam Lacosamide Tiagabine Gabapentin Pregabalin Ethosuximide Vigabatrin
What is anti-epileptic hypersensitivity syndrome and what are the symptoms?
Rare but potenially fatal syndrome associated with some anti-epileptics
Symptoms - show 1-8 weeks after exposure
Fever, Rash, Lymphadenopathy
Liver dysfunction
haematological, renal and pulmonary abnormalities, multi organ failure.
Which medicines is Anti-epileptic hypersensitivity syndrome associated with? (8)
Carbamazepine Lacosamide Lamotrigine Oxacarbazepine Phenobarbital Phenytoin Primidone Rufinamide
What is the MHRA (2008) regarding anti-epileptics?
Increased risk of suicidal thoughts and behaviour
How should anti-epileptics be withdrawn and what is there a risk of?
Slowly - risk of seizure recurrence
especially with barbiturates and benzodiazepines
What must a patient who drives do if they have a seizure of any type?
Inform the DVLA and stop driving
How long do patient’s who have had an unprovoked/single isolated seizure have to wait for before being able to drive again? What must they be cleared of?
What if a patient has established epilepsy?
6 months
Can resume once they have been assessed as fit to drive and do not suggest future risk
Established - CAN drive if they are not a danger to public, compliant with meds and follow up. Must be seizure free for at least 1 year & have a history of unprovoked seizures.
If a patient has had a seizure whilst asleep, how long do they have to wait before driving again?
1 year from the date of each seizure unless:
a history or pattern of sleep seizures has been established over 1 year from date of first sleep seizure.
OR
established pattern of purely asleep seizures ove3 years if pt has previously had seizures whilst awake.
When else does the DVLA advise that patients should not drive during…
During medication changes or withdrawal.
Wait 6 months after last dose.
Outline treatment summary of FOCAL/PARTIAL seizures with or without generalisation
1st/2nd/Adjunct/Tertiary
1st line:
Carbamazepine
Lamotrigine
2nd:
Oxacarbazepine
Sodium Valproate
Levetiracetam
If monotherapy is unsuccessful then adjunct: Carbazepine Clobazam Gabapentin Lamotrogine Levetiracetam Oxacarbazepine Sodium Valproate Topiramate
If ineffective/ not tolerated then specialist advise on tertiary options: Eslicarbazepine acetate Lacosamide Phenobarbital Phenytoin Pregabalin Tiagabine Vigabatrin Zonisamide
Outline treatment summary of TONIC CLONIC (generalised) seizures.
1st/2nd/Adjunct/Tertiary
1st line: Sodium Valproate (except in females who are pre-menopausal)
2nd:
Lamotrogine
if established tonic clonic then either one (sodium val or lamo) can be prescribed
Alternative 1st line:
Carbamazepine
Oxacarbazeopine
but may exacerbate myoclonic and absence seizures
Adjunct: Clobazam Lamotrogine Levetiracetam Sodium valporate Topiramate
Outline treatment summary of ABSENCE seizures.
1st/2nd/Adjunct
Which are not recommended?
1st line:
Ethosuximide
Sodium valproate (should be used esp if high risk of tonic-clonic seizures)
2nd:
Lamotrigine
Or if still not working - a combination of any two of above drugs.
NOT RECOMMENDED (same as myoclonic): Carbamazepine Gabapentin Oxacarbazepine Phenytoin Pregabalin Tiagabine Vigabatrin
Outline treatment summary of MYOCLONIC seizures.
1st/2nd/Adjunct/Tertiary
1st line: Sodium Valproate (not premenopausal females)
2nd:
Topiramate (* less favourable side-effects)
Levetiracetam
Adjunct: combo of two of above drugs.
NOT RECOMMENDED (same as absence): Carbamazepine Gabapentin Oxacarbazepine Phenytoin Pregabalin Tiagabine Vigabatrin
Outline treatment summary of ATONIC & TONIC seizures.
1st/2nd/Adjunct/Tertiary
Usually seen in childhood - associated with cerebral damage or mental retardation.
1st line: Sodium Valproate (except premenopausal females)
Adjunct:
Lamotrigine
Tertiary under specialist
Rufinamide
Topiramate
For what type of seizures are these NOT RECOMMENDED for use: Carbamazepine Gabapentin Oxacarbazepine Phenytoin Pregabalin Tiagabine Vigabatrin
- Absence
- Myoclonic
- Atonic & Tonic
What else is Gabapentin licensed and unlicensed for?
Licensed - neuropathic pain
Unlicensed - migraine prophylaxis
What else is Pregabalin licensed for? (2)
Neuropathic pain
Generalised anxiety disorder
What are the immediate measures to manage status epilepticus? (4)
- Positioning the patient to avoid injury
- supporting respiration
- maintaining blood pressure
- correction of any hypoglycaemia
What should be given if alcohol abuse is suspected in status epilepticus?
Parenteral thiamine
What should be given if pyridoxine hydrochloride deficiency is suspected in status epilepticus?
Pyridoxine hydrochloride
Seizures lasting longer than 5 mins should be treated urgently with…
Intravenous Lorazepam
repeated after 10mins if seizures resume or fail to respond
Intravenous diazepam can also be used for seizures lasting longer than 5mins …but what is there a risk of?
High risk of thrombophlebitis (inflammation of a vein relating to a blood clot)
Why can’t intramuscular or suppository diazepam be used for seizures lasting longer than 5mins?
Absorption is too slow
What should the patient be monitored for when giving IV diazepam or lorazepam? (2)
- Respiratory depression
2. Hypotension
If there are no resuscitation facilities available for status epileptics ..what can be given? (2 options)
- Diazepam - rectal solution
2. Midazolam - oral solution
What would you do if seizures didn’t stop after 25mins or recur after treatment with benzodiazepines?
1. phenytoin or 2. fosphenytoin sodium (phenytoin pro-drug) or 3. phenobarbital sodium
What are the 3 indications for Carbamazepine?
2 unlicensed?
- Focal seizures
- Bipolar when unresponsive to lithium
- Trigeminal neuralgia
- Alcohol withdrawal
- Diabetic neuropathy
What is the MoA of carbamazepine?
Binds to Na channels to prevent action potential
Important adverse effects of Carbamazepine
- Nausea
- Dizziness
- Fatigue
- GI discomfort
- Odema
- Hyponatraemia
- Vomiting
- Thrombocytopenia
- Skin reactions - red man / rash
- Vision disorders - nystagmus
- Leucopenia
- Eosinophilia
In which patients should carbamazepine be prescribed with caution in due to toxicity? (3)
- Renal
- Hepatic
- Cardiac
The efficacy of anti-epileptics is reduced by drugs that lower the seizure threshold. Give 4 examples?
- SSRIs
- Tricyclic antidepressants
3. - Isoniazid ?
Switching between different oral formulations of carbamazepine should be avoided …why?
Bioavailability between them differs
Which anti-epileptics have long half-lives so can be given once daily at bedtime? (4)
- Lamotrigine
- Perampanel
- Phenobarbital
- Phenytoin
Scenerio: Unplanned pregnancy & on antiepileptic. Should pt stop meds or continue?
What’s the pathway of care…
Pt should continue on medication as it’s too late to start the withdrawal period.
Risk of harm to mother or fetus from convulsive seizures outweighs the risk of continued therapy.
To reduce risk of neural tube defects - folate supplementation is advised before conception and 1st trimester.
Conc of antiepileptic drugs in plasma can change during pregnancy - phenytoin, carbamazepine and lamotrigine should be adjusted & others monitored.
What should be administered at birth to minimise risk of neonatal haemorrhage associated with antiepileptics?
Vitamin K injection
Newborn can experience withdrawal effects of which antiepileptic drugs? (2)
- Benzodiazepines
2. Phenobarbital
Breastfeeding - babies should be monitored for development as well as serum levels for meds that readily pass into breast milk causing high infant serum -drug concentration. Which are they? (4)
- Lamotrigine
- Ethosuximide
- Primidone
- Zonisamide
Withdrawal effects can occur in infants if mother stops breast feeding suddenly – if she is taking which meds? (3)
- Lamotrigine
- Primidone
- Phenobarbital
Which anti epileptic should patients be warned to look out for signs of fever, rash, mouth ulcers, bruising, bleeding?
Carbamazepine
Signs of blood, hepatic or skin disorders
Patients should be told how to spot signs of blood disorders: fever, mouth ulcers, bruising or bleeding.
Which antiepileptics should have this advice?
Blood counts needed.
- Ethosuximide