Epilepsy

Question 1

What is a seziure

Answer 1

A sustained and synchronised electrical discharge in the brain causing symptoms and signs

Question 2

What are the excitatory and inhibitory neurotransmitters

Answer 2

Excitatory - Glutamate and aspartate which act on NMDA/ AMPA receptors causing a sodium and calcium influx.
Inhibitory - GABA (in CNS) or Glycine (in spinal cord) which act on the GABA receptor causing chloride influx

Question 3

What are the different seizure types?

Answer 3

• Generalised tonic-clonic.
• Partial seziures with: lost awareness, motor phenomena, sensory phenomena, phycological phenomena or cognitive phenomena

Question 4

What is epilepsy?

Answer 4

A tendency to have recurrent unprovoked seizures

Question 5

What are the causes of epilepsy and the classification?

Answer 5

• Most are unknown,
• Can also be vascular, hippocampal sclerosis, infection or trauma.
• Classifications are focal epilepsy (localised onset, usually scarring) or genetic generalised (generalised onset)

Question 6

What is status epilepticus and the treatment?

Answer 6

When a seizure continues for more than 5 mins.
First line treatment is benzodiazepine either IV lorazepam or IV/rectal diazepam. This can be repeated. If seizures continue after second dose of benzo then give IV phenytoin or valproate

Question 7

Explain the management of a seizure

Answer 7

• Prevent injury and respiratory obstruction (put in recovery position)
• Call ambulance if it continues for >5m, its their first seizure or they have a new neurological deficit. These patients will need further investigation

Question 8

When do you start treatment after a seizure?

Answer 8

If the recurrence risk after the first seziure is high or they’ve had more than 2 seizures

Question 9

What are some of the targets of anti-epileptic drugs pre synaptically?

Answer 9

• Sodium channels as influx causes excitability. Inhibitors are carbamazepine and lamotrigine.
• Potassium channels as efflux reduces excitability. Channel activity enhanced by retigabine
• Inhibition of NT release by levetriacetam
• Calcium channel inhibitors eg, gabapentin

Question 10

What are the targets of anti-epileptic drugs on the GABAergic system?

Answer 10

• Inhibitor of the GABA transporter by tiagabine.
• Inhibitors of GABA degradations by Valproate

Question 11

What are the targets of anti-epileptic drugs post synaptically?

Answer 11

• Increased GABA receptor activity via benzodiazepines, topiramate. This reduced neuronal excitability

Question 12

What are the drugs of choice for localised onset epilepsy and generalised onset epilepsy?

Answer 12

Localised - Levetiracetam, lamotrigine or carbamazepine.
Generalised - Valproate (teratogenic), levetiracetam or lamotrigine