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PR3153 > IC6 Seizure & Epilepsy 1 > Flashcards

IC6 Seizure & Epilepsy 1 Flashcards

1
Q

Which age populations do epilepsy peak in?

There are 2 age groups in which epilepsy peaks in:
1. <1yo
2. People 20-40yo
3. People 41-60yo
4. People >60yo

A
  1. <1yo
  2. People >60yo
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2
Q

How many times more likely is a person with epilepsy at premature death?

A

2 to 3 times more likely to have premature death

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3
Q

When is the premature death risk the highest after diagnosis?

A

The risk of premature death is highest within the first 12 months of diagnosis.

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4
Q

What are the 3 risk factors of Sudden Unexplained Death in Epilepsy (SUDEP)?

A
  1. Presence & frequency of generalized tonic-clonic seizures
  2. Nocturnal seizures
  3. Lack of seizure freedom
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5
Q

What is the definition of seizure?

A

It is a paroxysmal event due to an abnormal hypersynchronous discharge from a mass of CNS neurons.

A seizure occurs when there is excessive synchronous depolarization, usually starting from defined region before spreading to other regions.

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6
Q

What are the criteria to diagnose a patient with epilepsy?
(There are 2 criteria. As long as a patient has 1 of them, they can be diagnosed with epilepsy)

A
  1. At least 2 unprovoked seizures occurring >24hrs apart.
  2. One unprovoked seizure + a ≥60% probability of further seizures, occurring over the next 10 years
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7
Q

What are the differences between acute, remote and unprovoked seizures?

A

Acute: Seizures that occur due to an immediate recognizable stimulus

Remote: Seizures that occur longer than 1 week following a disorder that can increase risk of developing epilepsy

Unprovoked: Seizures that occurs with no known cause

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8
Q

There are many potential causes of acute seizures.

Can you name the 4 main types of causes?

A
  1. Metabolic
  2. Toxic substances / drugs
  3. Structural
  4. Infection / inflammation

Metabolic:
- Hyponatremia
- Hypocalcemia
- Hypomagnesemia
- Hypoglycaemia

Toxic substances / drugs:
- Illicit drugs - e.g cocaine, amphetamines
- Drugs - e.g Carbapenems, baclofen, tricyclic anti depressants
- ETOH (withdrawal & intoxication)
- Benzodiazepine withdrawal

Structural:
- Stroke
- Traumatic brain injury

Infection/inflammation:
- CNS infection
- Febrile illness

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9
Q

Can we assume that a patient’s seizure is definitely caused by a drug?

A

No.

If a patient does experience seizures, we are usually never able to say that the seizure is caused by the drug. There are many other factors in play which can cause the seizure.

For example:
- Previous seizures
- Structural or functional brain abnormalities
- Concurrent drug use

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10
Q

What are characteristics of a drug that can induce seizure?
(There are 4 factors)

A
  1. The drug’s effect on neurotransmission
  2. Time course
  3. Concentration of drug reaching the brain
  4. Susceptibility of the individual patient
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11
Q

What are 3 factors that makes a person more susceptible to having seizures?

A
  1. Having previous seizures
  2. Structural or functional brain abnormalities - e.g stroke
  3. Concurrent drug use
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12
Q

List out the 5 common drugs that we know that contribute to seizures:

A
  1. High dose b-lactams
  2. Analgesia - opioids (e.g meperidine, tramadol)
  3. Antipsychotics - clozapine
  4. Immunosuppressant - cyclosporine
  5. Stimulants
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13
Q

What is status epilepticus?

A

A seizure that lasts longer than 5 minutes, or having more than 1 seizure within a 5 minutes period, without returning to a normal level of consciousness between episodes is called status epilepticus.

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14
Q

What are non-epileptic events?

A

Non-epileptic events - abnormal uncontrollable psychic, sensory and/or motor manifestations, which resemble epileptic seizures, but are not related to abnormal epileptiform discharges.

These events look like seizure, but are not related to it

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15
Q

What are the 2 types of non-epileptic events?

A
  1. Psychogenic non-epileptic “seizures” (PNES)
  2. Physiological non-epileptic events

PNES is:
- Involuntary
- Caused by stressful psychological experiences or emotional trauma
- Partial alteration of consciousness level w partial preservation of awareness.

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16
Q

What are the 2 things we think of straight away when we think about seizures?

A
  1. Hyperexcitability
  2. Hypersynchronization
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17
Q

Explain what is hyperexcitabiity.

A

It is when a neuron is more likely to depolarize.

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18
Q

What are the 4 main factors that can lead to hyperexcitability?

A
  1. Excessive excitatory neurotransmitters (e.g glutamine, acetylcholine, histamines, etc)
  2. Insufficient inhibitory neurotransmitters (e.g GABA, dopamine)
  3. Abnormal intra & extracellular substances
  4. Voltage- or ligand-gated ion channels
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19
Q

What are the 4 types of voltage gated ion channels involved?

A
  1. Na+ Channel
  2. K+ Channel
  3. Ca2+ Channel
  4. Cl- channel
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20
Q

Which part of the brain gets scarred when there is a seizure?
(Hint: the part of the brain responsible for memory)

A

Hippocampus.

The scarring of the hippocampus is aka hippocampal sclerosis.

The scarring contributes to synchronization & generation of epileptiform activity.

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21
Q

What is the mode of onset in:
1. Focal onset seizure
2. Generalized seizure
3. Secondarily generalized seizure

A

Focal onset seizure - seizure begin only in 1 hemisphere

Generalized seizure - seizure begins in both hemisphere

Secondarily generalized seizure - seizure begin in one hemisphere, then spreads to the other

22
Q

What are the 3 characteristics that we look at to determine the type of seizure?

A

There are 3 clinical presentations to look at to determine the characteristics of a seizure:

  1. Site of focus
  2. Degree of “irritability” of the areas of the brain surrounding the focus
  3. Intensity of the impulse
23
Q

What are the 4 phases of a seizure?

A
  1. Prodromal
  2. Early ictal (“aura”)
  3. Ictal
  4. Post-ictal

Ictal - the period of a seizure

24
Q

What is the clinical presentation of tonic clonic (GTC) seizures?

A
  1. Begins w stiffening of the limbs (tonic phase), followed by jerking of limbs and face (clonic phase)
  2. During tonic phase, breathing may ↓ or cease
  3. The nailbeds, lips & face will turn blueish. Colour will typically return during clonic phase but may be irregular
  4. Clonic phase usually lasts 1 min. After the clonic phase, the brain is extremely hyperpolarised and insensitive to stimuli.
  5. Urine can leak out uncontrollably, along w biting of tongue or nside of mouth. Breathing may be noisy & laboured
  6. After the seizure, pt may have headache, confusion, lethargy, and feel sleepy
  7. Full recovery takes several minutes to hours
25
Q

What are the characteristics for:
- Clonic seizures

A
  1. Asymmetrical & irregular jerking
  2. Most frequent in neonates, infants or young children
26
Q

What are the characteristics for:
- Tonic seizures

A
  1. Sudden loss of consciousness & rigid posture of entire body, lasting about 10-20s
  2. It is a type of seizure that occurs in those with Lennox-Gastaut syndrome

Lennox-Gastaut syndrome is a severe form of epilepsy.

27
Q

What are the characteristics for:
- Myoclonic seizures

A

Has rapid & brief contraction of bodily muscles. Usually occurs on both side of the body concurrently

28
Q

What are the clinical presentation for
- Focal onset seizures / simple partial seizures

(1) Motor symptoms
(2) Sensory symptoms
(3) Autonomic symptoms
(4) Psychic symptoms

A

(1) Motor symptoms:
- Clonic movement of the arm, shoulder, face, or leg
- Unable to speek or speech slurring

(2) Sensory symptoms:
- numbness or tingling sensation
- visual disturbances
- rising epigastric sensation

(3) Autonomic symptoms:
- Sweating, salivation, pallor
- BP, HR

(4) Psychic symptoms:
- flashback, deja vu
- Visual, auditory, gustatory, olfactory hallucinations
- Fear, depression, anger & irritability

29
Q

What are the clinical presentation of absence seizures?

A
  1. A lapse in awareness that begins and ends abruptly
  2. Sometimes mistaken as persistent staring
  3. Last only a few seconds
  4. Often undetected even if there are 50-100 attacks per day
  5. More common in children than in adults
  6. 1st onset usually occur at 4-12yo, rarely after 20yo
  7. May be mistaken for complex partial seizures - implication in wrong choice of medication prescribed
30
Q

What is the difference between absence seizures and complex partial seizures?

A
  1. Absence seizures are never preceded w auras
  2. Absence seizures last a few seconds - much shorter than complex partial seizures
  3. Begins frequently & ends abruptly
  4. Produce characteristic EEG - “3Hz spike waves”
31
Q

What is the clinical presentation of atonic seizures?

A
  1. Most severe form is when all postural tone is suddenly lost, causing collapse to the ground
  2. Episodes are short and often followed with immediate recovery
  3. Occur at any age
  4. Always associated w cerebral damage and learning disability
  5. Common in epilepsies w severe symptoms - e.g. Lennox Gastaut syndrome
32
Q

What are the steps to take to diagnose a patient with the type of seizure that they have experienced?

A
  1. Thorough history taking
    - Finding out the onset, duration & characteristics of a seizure
    - Accurate history is best obtained by an observer of the event
    - Patient is useful in describing details of the auras, preservation of consciousness & how they feel post-ictal state
  2. Neurological examination
  3. Concomitant medical conditions
33
Q

After talking to the patient & observers of an episode of a seizure, they listed out some common characteristics.

What are the possible characteristics that they could have listed that could lead you to think that it is a seizure and not other diseases?

A

Classical characteristics of seizure:
1. Aura
2. Cyanosis
3. Loss of consciousness
4. Motor manifestations
5. Generalised stiffness of limbs & body
6. Jerking of limbs
7. Tongue biting
8. Urinary incontinence
9. Post-ictal confusion
10. Muscle soreness

These symptoms will help you differentiate seizures from:
- Transient ischaemic attack
- Migraine
- Non-epileptic seizures

34
Q

What is the tool to measure brain activity and to analyse epileptiform discharges?

A

An electroencephalography (EEG)

EEG will show epileptiform discharges if patient has seizure and epilepsy.

No epileptiform discharges will be seen on non-epilepsy events

35
Q

What are some of the limitations of an EEG?

A
  1. EEG alone is not enough to diagnose a patient with epilepsy.
    - Not all epileptic patients will show an abnormal EEG
    - Normal people may have abnormal EEG as well
  2. EEG can be expensive & labour intensive
36
Q

What do we order for an adult patient w 1st episode of seizure?

A

We order an MRI.

MRI helps us to identify any possible focal lesions that triggered the seizure.

Focal lesions are:
1. Tumour
2. Remote injury (old stroke, etc.)
3. Vascular malformation
4. Mesial temporal sclerosis
5. Focal cortical sclerosis

37
Q

What other test do we order for a patient to confirm that they experienced a seizure?

A

We order lab test.

We want to check:
1. Electrolytes - rule out any electrolyte abnormalities
2. Creatine kinase - Raised after a GTC episode

38
Q

This is just a short summary of what we have covered so far:

A
  1. Suspect 1st ever seizure in an adult patient
  2. Proceed to obtain history from observer
  3. Conduct neurological test, physical examination, and lab tests
  4. Once we have confirmed that patient experienced seizure, assess if seizure is acute (has a cause) or unprovoked
    - If seizure is acute, treat the provoking factors.
  5. If seizure is unprovoked (no known cause), conduct MRI and EEG.
  6. Estimate the risk of seizure recurrence from the MRI and EEG
  7. Diagnose patient with epilepsy if patient presents with:
    a. At least 2 unprovoked seizures occurring >24hrs apart.
    b. One unprovoked seizure + a ≥60% probability of further seizures, occurring over the next 10 years
39
Q

After looking at the MRI and EEG for 1st seizure, we can determine risk of recurrence.

What is the likely risk of recurrence within the next 5 years after the 1st episode of seizure?

A

The risk of seizure in the next 5 years after the 1st episode is 30%.

People that present with these factors are at an increased risk of having recurrent seizures:
1. Epileptiform abnormalities detected on EEG
2. Prior brain insult (e.g stroke, brain trauma)
3. Structural abnormality in brain imaging
4. Nocturnal seizures

40
Q

What are the 4 factors to consider whether we should start treatment for seizures?

A

We consider starting treatment for seizures in patient with:
1. Recurrent risk
2. Potential seizure morbidity
3. Risk of treatment
4. Personal circumstances - e.g work, need for driver’s license, etc.

Evidence has shown that treatment can help reduce the risk of 2nd seizure.

41
Q

What are treatment goals for epilepsy?

A

The goals for treating epilepsy are:
1. Absence of epileptic seizures
2. Absence of anti-seizure medication side effect
3. Optimal quality of life for patients

42
Q

What are non-pharmacological treatment measures for seizures?

[Pharmacological management for seizures will be discussed in IC7]

A

The non-pharmacological measures for seizures are:
1. Ketogenic diet
2. Vagus nerve stimulation (VNS)
3. Responsive neurostimulator system (RNS)
4. Surgery

43
Q

What is a ketogenic diet?

A

It is a diet that is low carbohydrates and high in fat.

This helps to induce ketosis - a metabolic state where your body burns fat for energy instead of glucose.

44
Q

What is the down side to a ketogenic diet?

A

It is not sustainable in the long run.

45
Q

How is a vagus nerve stimulator machine used?

A

Vagus nerve stimulator have electrodes that are attached to the left branch of the vagus nerve.

The electrodes are then connected to the stimulator which delivers cyclical stimulation.

During a seizure, a magnet can be placed next to the device for “on demand” stimulation.

46
Q

What is a Responsive neurostimulator system (RNS) and how does it operate?

A

A responsive neurostimulator system (RNS) is a system that has:
1. Stimulators implanted in the skull, under the scalp
2. Leads that are implanted in the brain

The RNS is used as an adjunctive therapy in pt who:
1. Are refractory to ≥2 antiepileptic medications
2. Have ≤2 areas in the brain that have electrical discharges that triggers seizures
3. Have frequent & disabling symptoms

RNS monitors the electrical activity of the patient and delivers brief pulses of stimulation when it detects possible activity that could lead to a seizure.

47
Q

How does epilepsy surgery help?

A

Epilepsy surgery is only used in selected forms of epilepsy. It helps to achieve improvement of symptoms or seizure-free status.

48
Q

Can people who have experienced seizure drive in Singapore?

A

No. Anyone that has experienced seizure are not allowed to drive in SG.

49
Q

What to educate a patient on seizures?

A
  1. Teach the patient how to identify & avoid seizure triggers
  2. Inform patient of side effects & DDI
  3. Avoid driving, swimming, handling firearms (e.g NS)
  4. Have a seizure diary
50
Q

IC6 summary

A
  • Not all pt who has seizures have epilepsy
  • Neuronal hyperexcitability & hypersynchronization of local circuits have greater likelihood of epileptiform activity
  • To diagnose a pt, accurate history is key. EEG helps to confirm.
  • ILAE guidelines help to distinguish the different types of seizures
  • Important to administer seizure first aid to ↓ harm
  • Treatment - non-pharmacological options

PR3153 (18 decks)

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