Epilepsy

Question 1

How is epilepsy defined?

Answer 1

It is defined by recurrent unprovoked (= spontaneously occurring) seizures

Question 2

What is an epileptic seizure?

Answer 2

paroxysmal change in behaviour due to synchronised rhythmic firing of populations of CNS neurons

Question 3

How often does epilepsy occur in the population?

Answer 3

1% of the general population has epilepsy
5% of the general population has a risk of one seizure in the lifetime

Question 4

When is the probablity of an epileptic seizure the highest?

Answer 4

U-shaped distibution: childhood-adolescence (0-20) + older age (60-80)

Question 5

When can a person be diagnosed with epilepsy?

Answer 5

• 2 unprovoked seizures, > 24 hours apart
• 1 unprovoked seizure & causative CNS disease and pathological EEG alterations

Question 6

What is a focal seizure?

Does it originate in one hemisphere or in both?

Answer 6

initial symptoms/signs (clinical and EEG) indicate origination of seizure activity within an area of one hemisphere

Clinical data: partial onset; seizures during sleep; focal slowing or hyperexcitability; structural lesion

Question 7

What is a generalised seizure?

Does it originate in one hemisphere or in both?

Answer 7

initial symptoms/signs indicate origination of seizure activity simultaneously in both hemispheres

Clinical data: generalized seizures; 30 minutes after awakening; positve family history; generalized hyperexcitability; negative MRI

Question 8

What types of focal seizures are there?

Answer 8

1. focal aware => preserved concioussness, aware of having a seizure
2. focal impaired awareness => impaired concioussness, staring (additional symptoms of focal aware, automatic behaviors like lip smacking, fumbling, wandering)
3. focal to bilateral tonic-clonic (secondary) => loss of concioussness, falling on the ground

Question 9

What types of generalised seizures are there?

Answer 9

1. Absence seizures → absent staring, non-motor, can occur in clusters
2. Tonic seizures → stiff muscles of the back, arms, and legs
3. Atonic seizures → “drop seizures”, loss of muscle control
4. Clonic seizures → repeated jerking; the neck, face, and arms
5. Myoclonic seizures → brief jerks and twitching; upper body, arms, and legs
6. Tonic-clonic seizures → the most dramatic, stiffness and shaking, loss of consciousness

Question 10

Where are focal aware seizures localized?

Answer 10

1. temporal lobe (65%):
   -lateral (10%) — auditory symptoms
   -mesial (90%) — psychic or autonomic symptoms (deja vu, fear (amygdala))
2. frontal lobe (25%) - tonic (rigility/stiff) / clonic (jerking) movements
3. occipital lobe (5%) - visual symptoms
4. parietal lobe (5%) - paraesthesia (tickling), vertigo

sum to 100%, no multiple localizations — very rare + a difficult case: seizure and abnormality — are there causation relations?

Question 11

What is an epileptic syndrome in focal epilepsy?

ILAE: epileptic syndrome is “a characteristic cluster of clinical and EEG features, often supported by specific etiological findings (structural, genetic, metabolic, immune, and infectious).”

Answer 11

history/clinical data
* partial or partial onset seizures
* seizures during sleep

EEG
* focal slowing or hyperexcitability

cMRI
* structural lesion

Question 12

What is an epileptic syndrome in generalised epilepsy?

Answer 12

history/clinical data
* generalised seizures
* 30 min after awakening
* positive family history

EEG
* generalised hyperexcitability

cMRI
* not helpful, always negative

Question 13

What can be the etiology of epilepsy?

Structural vs. genetic epilepsy

Answer 13

Structural
1. Hippocampal sclerosis
2. Malformations of cortical development
3. Vascular malformations
4. Prenatal injuries and developmental abnormalities (oxygen deficiency, ASD, malnutrition)
4. Postnatally acquired CNS lesions
-infectious/inflammatory causes (HIV, viral encephalitis, parasitic infections)
-neoplasia
-cerebro-vascular accidents
-traumatic brain injury
-neurodegeneration

Genetic
1. ion channel mutation (Na+, K+, Cl–channels)
2. receptor mutation (GABA-receptor, acetyl-cholin-receptor)
3. ion transporter mutation (Na+-K+-ATPase)

Question 14

What are the main differnces bertween syncope and tonic-clonic seizure?

Answer 14

syncope vs. tonic-clonic seizure
duration: < 30s vs. 1-2min
reorientation: <30s vs. 4-45 min
trigger: 50% vs. almost never
tongue biting: rare vs. frequent

Mind: convulsions (even though arrhythmic vs. rhythmic), falls and eyes open can be charasteristical of both

Question 15

What are the features of psychogenic non-epileptic seizures?

Answer 15

• duration: > 10 min
• motor convulsions fluctuating
• put on, deflectable
• tip of the tongue biting
• never out of sleep
• injuries rare
• ictal EEG unchanged
• eyes closed

Question 16

What is myoclonus?

Answer 16

Myoclonus is a type of muscle twitching or jerking that is caused by sudden, brief, and irregular muscle contractions. e.g. hyperventilation-induced myoclonus as a result of breathing too rapidly and deeply => decrease in carbon dioxide levels in the blood

Question 17

What is PNES?

Answer 17

Psychogenic non-epileptic seizure:
* resemble epileptic seizures but are not the result of abnormal electrical discharges in the brain
* the spike and spike pattern is not seen on EEG
* psychosomatic – physical manifestation of psychological distress

Question 18

What does the risk of reoccurence of an epileptical seizure depend on?

Answer 18

Risk for seizure reoccurence
* if you have one seizure (5%) -> 30-40% of the second seizure
* if you have two seizures (diagnosis) -> 60% of reoccurence

Question 19

Can epilepsy be modified or treated? How does it influence treatment options?

Answer 19

The chronic disorder epilepsy cannot be modified or treated. Treatment options are antiseizure medication (ASM) and secondary prophylaxis (preventing syptoms occurence)

Question 20

What is the treatment goal in chronic epilepsy

Answer 20

maintenance of normal life style = complete seizure freedom + no or minimal substance adverse effects

Question 21

What are the targets of treatment?

Answer 21

Na+ and Ca2+ channels, GABA system, glutamate receptors (AMPA & NMDA)

Question 22

How successful is treatment with antiepileptic drugs?

Answer 22

60%: good prognosis, seizure-free with 1. or 2. monotherapy, no relevant adverse effects, commonly seizure-free with AED termination
30%: pharmacoresistant with polytherapy
10%: seizure-free with polytherapy

Question 23

When is epilepsy surgery recommended? How successful it can be?

Answer 23

• pharmacoresistance
• identification of one epileptic focus with EEG
• suitable MRI lesion
• resection possible without persistent neurological/neuropsychological deficits
• • not younger than 17 years

58% of patients are seizure-free after 1 year follow up

Question 24

What are less invasive treatment options? Are they effective?

Answer 24

Laser treatment – MRI-guided borehole. Same 58% of patients seizure free

priniciple: thermal therapy

Question 25

What are most often side effects of antiepileptic drugs?

Answer 25

Side effects:
* specific for the drug
* dizziness (in the beggining => slower dosing)
* mood swings and irritability -> depression symptoms, even to suicidal attempts
* allergic reactions
* osteoporosis
* electrolyte disturbances
* loss of memory function

Question 26

What does ILAE 2017 Classification of Seizure types rely on?

Answer 26

It relies on onset region: focal vs. generalized vs. unknown