Epilepsy

Question 1

What is Epilepsy ?

Answer 1

Epilepsy is a chronic condition of repeated seizures

Question 2

What are Seizures ?

Answer 2

Seizures are abnormal, excessive or synchronous neuronal activity in the brain

Question 3

Difference between seizures and epilepsy ?

Answer 3

Seizures are the event (or symptom), epilepsy is the disorder

Question 4

What is Status epilepticus?

Answer 4

Status epilepticus is a prolonged seizure or when seizures recur frequently enough to prevent recovery between episodes (duration 20-30 minutes) – a medical emergency

Question 5

What is the fraction of people with epilepsy that have a family member with it?

Answer 5

Around 1/3 people

Question 6

70 % of epilepsy cases arise due to ?

Answer 6

Genetic factors but often with complex inheritance

Question 7

Only 1 % of all epilepsy cases are ?

Answer 7

Single-gene epilepsies (with simple genetic inheritance)

Question 8

The remaining 30% of epilepsy cases are due to?

Answer 8

• Injury
• Stroke
• Tumor
• Birth defects
• Infection and autoimmune diseases

Question 9

Examples of epilepsy syndromes ?

Answer 9

• Dravet syndrome
• Benign Rolandic Epilepsy (i.e. w/ centrotemporal spikes)
• Landau Kleffner syndrome (LKS)
• Rasmussen’s syndrome
• West syndrome

Question 10

What could be triggers of seizures ?

Answer 10

• Lack of sleep
• Drugs/alcohol
• Missing meals
• Fever
• Not taking medications
• Flashing lights
• Stress
• Monthly periods

Question 11

What seizure types are not considered part of epilepsy according to the International
League against Epilepsy (ILAE)?

Answer 11

• Febrile seizures (0.5 – 6 years old)
• Alcohol-withdrawal seziures
• Metabolic seizures (e.g. glucose)
• Toxic seizures (e.g. drug withdrawal)
• Convulsive syncope
• Acute concussive convulsion
• Seizures within first week after brain trauma, infection or stroke

Question 12

What is Electroencephalography (EGG) ?

Answer 12

An EEG is a test that detects abnormalities in your brain waves, or in the electrical activity of your brain

Question 13

Explain the seizure type - Partial ?

Answer 13

• Simple – patient remains
  conscious. Also known as ‘auras’
• Complex – patient has impaired consciousness
  if the seizure spreads to the
  reticular formation (in the brainstem)
• Partial seizures are also known as focal seizures

Question 14

Explain the seizure type - Generalised (tonic-clonic) ?

Answer 14

1. Normal record
2. Tonic (contractions; lose
   consciousness)
3. Clonic (jerks)
4. Coma
   - Lasts 3-5 min
   - Also known as grand mal seizures

Question 15

Explain the seizure type - Generalised (absence) ?

Answer 15

1. Occur in children
2. Patient stops, stares
   and is unaware; no
   motor disturbance
3. Rhythmic discharge;
   Spike-and-wave
   - Also known as petit mal seizures

Question 16

What are some other generalised seizures ?

Answer 16

Myotonic seizures and atonic (or drop) seizures

Question 17

Types of wave on a normal EEG ?

Answer 17

• Delta waves (0.5–4 Hz). Sleep and in children < 1 year old.
• Theta waves (4–7 Hz). Sleep and in young children.
• Alpha waves (8–13 Hz): Awake relaxation w/eyes closed
• Beta waves (13–30 Hz). Conscious thought (frontal lobes)
• Gamma waves (30–100 Hz). Working memory and attention

Question 18

What is the typical amplitude ?

Answer 18

About 25–100 mV

Question 19

As neuronal ensembles become more synchronised, voltage changes in the
EEG become ?

Answer 19

Larger and prominent over normal EEG waves

Question 20

What are sudden changes in activity referred to as ?

Answer 20

Paroxysmal activity

Question 21

Briefly explain abnormal waves on an EEG ?

Answer 21

• Sharp waves: Last 80-200 milliseconds.
• Spikes: very large, fast waves. Last < 80 ms.
• Spike & wave: >1 brief spikes followed by a slow wave (3 Hz) - typical of absence seizures
• Polyspikes: burst of spikes
• Polyspike & waves

Question 22

What does Ictal activity refer to ?

Answer 22

• Ictal refers to a sudden physiological attack (e.g. stroke, seizure, headache)
• In the context of epilepsy, ictal refers to the seizure event.

Question 23

During the interictal period abnormal activity is confined to the seizure focus by?

Answer 23

Inhibitory surround, but this breaks down and/or is overcome at the onset of a focal seizure, leading to synchronisation

Question 24

Explain seizure spread in a partial seizure ?

Answer 24

Spread locally via:

1. Intrahemispheric fibres
2. Corpus callosum
3. Subcortical centers

Question 25

Explain seizure spread in a generalised seizure ?

Answer 25

Spread locally via: | - Thalamus