Epilepsy Flashcards
Epilepsy
Epilepsy is a common neurological condition characterised by recurrent seizures.
It should be remembered that epilepsy is not the only reason people have seizures
Other than epilepsy; what are the other causes of seizures?
Insult to the brain, infection, trauma or metabolic disturbance, tumors
Febrile convulsions
Typically occur in children between the ages of 6 months and 5 years
Usually occur early in a viral infection as the temperature rises rapidly
Seizures are typically brief and generalised tonic/tonic-clonic in nature
What age do febrile convulsions usually occur?
Typically occur in children between the ages of 6 months and 5 years
Alcohol withdrawal seizures
Occur in patients with a history of alcohol excess who suddenly stop drinking, for example following admission to hospital
When do alcohol withdrawal seizures occur after stopping alcohol?
36 hours following cessation of drinking
What can be done to prevent alcohol withdrawal seizures in hospitals?
given benzodiazepines following cessation of drinking to reduce the risk
Psychogenic non-epileptic seizures
Previously termed pseudo seizures, describes patients who present with epileptic-like seizures but do not have characteristic electrical discharges.
Patients may have a history of mental health problems or a personality disorder
Partial focal seizures can be describes as either simple or complex; what is the difference between the two?
a. Simple: without impaired consciousness
b. Complex: with impaired consciousness
What are focal seizures?
Previously termed partial seizures
These start in a specific area, on one side of the brain
What are the six types of generalized seizures?
o tonic-clonic (grand mal) o tonic o clonic o typical absence (petit mal) o myoclonic: brief, rapid muscle jerks o atonic
What are generalized seizures?
These engage or involve networks on both sides of the brain at the onset
Consciousness lost immediately.
How are generalized and focal/partial seizures differentiated?
Consciousness lost immediately in generalized, in partial consciousness may or may not be lost
What investigations are done following the first seizure in a patient?
Following their first seizure patients generally have both an electroencephalogram (EEG) and neuroimaging (usually an MRI).
When are epileptics drugs started in epileptic seizures?
Most neurologists now start antiepileptics following a second epileptic seizure.
What is the first line drug in generalized seizures?
sodium valproate
What is the first line drug in focal seizures?
carbamazepine
When can patients drive following a seizure for the first time?
Cannot drive for 6 months following a seizure.
When can patients with established epilepsy drive?
For patients with established epilepsy they must be fit free for 12 months before being able to drive
What epilepsy medications are tetratogenic?
antiepileptics are generally teratogenic, particularly sodium valproate.
What is the mechanism of action of sodium valproate?
Increases GABA activity
Although the mechanism of action remains to be elucidated, valproate sodium increases concentrations of gamma-aminobutyric acid (GABA) in the brain, probably due to inhibition of the enzymes responsible for the catabolism of GABA.
Side effects of sodium valproate
increased appetite and weight gain alopecia: regrowth may be curly P450 enzyme inhibitor ataxia tremor hepatitis pancreatitis thrombocytopaenia teratogenic (neural tube defects)
Side effects of Carbamazepine
- P450 enzyme inducer
- dizziness and ataxia
- drowsiness
- leukopenia and agranulocytosis
- syndrome of inappropriate ADH secretion
- visual disturbances (especially diplopia)
Mechanism of action of Carbamazepine
Binds to sodium channels increasing their refractory period
Mechanism of action of Lamotrigine
Sodium channel blocker
Side effects of Lamotrigine
Stevens-Johnson syndrome - The syndrome often begins with flu-like symptoms, followed by a red or purple rash that spreads and forms blisters. The affected skin eventually dies and peels off.
Stevens-Johnson syndrome is a medical emergency that requires treatment in hospital, often in intensive care or a burns unit.
When is Lamotrigine used in epilepsy?
Used second line for a variety of generalised and focal seizures
Side effects of Phenytoin
P450 enzyme inducer dizziness and ataxia drowsiness gingival hyperplasia, hirsutism, coarsening of facial features megaloblastic anaemia peripheral neuropathy enhanced vitamin D metabolism causing osteomalacia lymphadenopathy
Mechanism of action of phenytoin
Binds to sodium channels increasing their refractory period
In the pre-hospital setting, an epilepsy seizure of more than 5-10 mins should be given rescue medication - what is this?
Benzodiazepines such as diazepam are typically used may be administered rectally or intranasally/under the tongue.
Patients with epileptic seizure of more than 10 mins not stopping despite benzodiazepines are referred to as what?
Status epilepticus.
This is a medical emergency requiring hospital treatment.
What is status epilepticus?
a single seizure lasting >5 minutes, or
>= 2 seizures within a 5-minute period without the person returning to normal between them
When patient has refractory status (seizure lasting for up to 45 minutes or more); what management is done?
General anesthesia
What are absence seizure features?
- absences last a few seconds and are associated with a quick recovery
- seizures may be provoked by hyperventilation or stress
- the child is usually unaware of the seizure
- they may occur many times a day
- EEG: bilateral, symmetrical 3Hz spike and wave pattern
Why is sodium valproate considered tetragenic?
Causes neural tube defects
