Epilepsy & Anticonvulsants

Question 1

What is epilepsy?

Answer 1

A disorder of the cerebral cortex characterised by sudden, excessive, synchronised neuronal discharges.

Question 2

What are the two main phases in epilepsy?

Answer 2

• Ictal Phase: The seizure or convulsion phase.
• Interictal Phase: The quiescent period between seizures, often showing abnormal spike activity on EEG.

Question 3

What is the prevalence of epilepsy?

Answer 3

Affects 0.5-1% of the population, with higher susceptibility in childten and the elderly.

Question 4

What are the two main causes of epilepsy?

Answer 4

• Idiopathic (70%): Genetic predisposition.
• Symptomatic: Congenital abnormalities, head trauma, infections, tumours

Question 5

Name the diagnostic tools used in epilepsy (4)

Answer 5

• EEG: Measures electrical brain activity
• PET: Monitors local metabolism
• MRI: Structure and volume
• fMRI (specific to brain function): Relates activity to structure

Question 6

What are generalised seizures?

Answer 6

Seizures that affect both hemispheres of the brain from the onset, typically with loss of consciousness.

Question 7

What are focal (partial) seizures?

Answer 7

Seizures originating in a specific brain region, which may remain localised or spread.

Question 8

What are the subtypes of generalised seizures? (6)

Answer 8

1. Tonic-Clonic (Grand-Mal): Muscle stiffness, convulsions, postictal confusion
2. Absence (Petit-Mal): Brief lapses in consciousness, 3 Hz spike-and-wave EEG.
3. Myoclonic: Sudden muscle jerks.
4. Atonic: Sudden loss of muscle tone
5. Tonic: Muscle stiffening.
6. Clonic: Rhythmic jerking.

Question 9

What is the primary excitatory neurotransmitter implicated in seizures?

Answer 9

Glutamate

Question 10

What is the primary excitatory neurotransmitter involved in controlling seizures?

Answer 10

GABA

Question 11

Name the key mechanisms of action for anticonvulsants. (4)

Answer 11

1. Na⁺ Channel Blockers: Phenytoin, Carbamazepine, Lamotrigine
2. Ca²⁺ Channel Blockers: Ethosuximide, Gabapentin
3. GABA Enhancement: Benzodiazepines, Barbiturates.
4. Glutamate Modulation: Topiramate, Levetiracetam.

Question 12

Which anticonvulsants are first-line for tonic-clonic seizures?

Answer 12

Phenytoin, Carbamazepine, Valproate.

Question 13

Which drugs are first-line for absence seizures?

Answer 13

Ethosuximide and Valproate

Question 14

What is SUDEP, and what are its risk factors?

Answer 14

Sudden Unexpected Death in Epilepsy, often linked to poorly controlled seizures and abrupt medication cessation.

Question 15

What is the role of surgery in epilepsy management? (2)

Answer 15

Resective Surgery: Removes epileptogenic foci (e.g., temporal lobectomy)

Electrode-Based Interventions: For monitoring and surgical planning.

Question 16

How do Na⁺ channel blockers prevent seizures?

Answer 16

By stabilising the inactivated state of Na⁺ channels, preventing repetitive neuronal firing.

Question 17

How does Levetiracetam work as an anticonvulsant?

Answer 17

Modulates synaptic vesicle release, reducing glutamate release.

Question 18

Which drugs are used for status epilepticus?

Answer 18

Benzodiazepines such as Lorazepam and Diazepam

Question 19

What is the hallmark EEG pattern of absence seizures?

Answer 19

3 Hz spike-and-wave discharges.