epilepsy

Question 1

What is a seizure?

Answer 1

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

Question 2

Describe the basics of epileptic activity

Answer 2

• Influx of ions

* Recurrent discharges -> tonic phase -> clonic phase

Question 3

What substances are responsible for excitation?

Answer 3

• EAA
• Action on NMDA/AMPA/kainate
• Na+/ Ca2+ influx

Question 4

What substances are responsible for inhibiton?

Answer 4

• GABA/Glycine
• Action on GABA-R
• cl- influx

Question 5

What are the seizure types?

Answer 5

•Generalised tonic-clonic 
•Partial seizures with: 
 - loss of awareness
 - motor phenomena 
 - sensory phenomena 
 - psychological phenomena 
 - cognitive phenomena

Question 6

What is epilepsy?

Answer 6

A tendency to have recurrent unprovoked seizures

Question 7

What are the causes of epilepsy?

Answer 7

• 57% unknown
• 11% vascular
• 7% hippocampal sclerosis
• 6% infection
• 6% trauma
• MCS, Tumour, degenerative

Question 8

What should be done when someone has their first seizure?

Answer 8

• Clinical diagnosis- take a history from someone who saw the seizure
• Investigation - cortical imaging, ECG
• Evaluate recurrence risk

Question 9

If a patient has a seizure what is the initial management?

Answer 9

• Secure the airway
• Administer oxygen
• Assess pulse, BP, respiration

Question 10

What should you do if a patient’s seizure continues beyond 5 minutes?

Answer 10

• Secure IV access and administer benzodiazepine
• Treat potential cause (IV glucose if hypo, IV thiamine is potential alcohol abuse)
• Assess blood glucose, oximetry, bloods, clotting screen , ABG, cardiac monitor

Question 11

If you come across someone having a seizure in public, what should you do?

Answer 11

• Prevent injury - recovery position
• Prevent respiratory obstruction
• Stay with them
• Call an ambulance if continuous for over 5 minutes, first seizure or new neurological deficit

Question 12

Explain the effects of AEDs

Answer 12

• Reduce presynaptic excitability enhance inhibition
• Can inhibit the voltage gated Na+ channels: carbamazepine
• Can increase the activity of the Voltage gated K+ channels: retigabine
• Inhibit the release of SV2A: levetiracetam
• Inhibit the voltage gated Ca2+ channel: gabapentin

Question 13

What are the effects of AEDs on the GABAergic system?

Answer 13

• They enhance the GABAergic system, by elevating the amount of GABA
• Target the GABA transporter, inhibiting the removal of GABA from the synapse: tiagabine
• Target the GABA metabolism, reducing the degrading of GABA: Valproate

Question 14

What are the effects of AEDs on post synaptic activity?

Answer 14

•Target the GABAA receptor. The GABAA receptor reduces neuronal excitability so drugs work by increasing this: benzodiazepines, topiramate, barbiturates

Question 15

Name 3 anti epilepsy drugs with a localised onset

Answer 15

• Lamotrigine
• Carbamazepine
• Levetiracetam

Question 16

Name 3 anti epilepsy drugs with a generalised onset

Answer 16

• Valproate
• Levetiracetam
• Lamotrigine