Epilepsy Flashcards

1
Q

What is a seizure?

A

Abnormal discharge of cerebral neurons firing all at once which cause a disturbance of consciousness, behavioural, motor and sensory function.

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2
Q

What is epilepsy?

A

Condition where seizures recur spontaneously.

Signs of epilepsy excluding seizures include evidence of tongue biting, incontinence and injury.

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3
Q

What are the types of epilepsy?

A

Focal/Partial
Generalised

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4
Q

What is a generalised seizures?

A

Seizure begins in both of the cerebral hemispheres and includes:

Motor seizures which include tonic, clonic, atonic, myoclonic.

Non-motor seizures are absence seizures which can be typical, atypical or myoclonic.

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5
Q

What are absence seizures?

A

A non-motor generalised seizure which occurs most commonly in children, accompanied with a blank stare. This occurs due to abnormal electrical signals in the corticothalamic pathways which are important for awareness and wakefulness. There are no postictal symptoms.

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6
Q

What are tonic seizures?

A

Muscle tone increases by stiffening through contraction and results in loss of balance and co-ordination and fall over. There are no post-ictal symptoms.

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7
Q

What are clonic seizures?

A

Shaking or jerking in the limbs. There are no post-ictal symptoms.

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8
Q

What are atonic seizures?

A

Sudden loss of muscle tone which can cause a person to go limp and lose balance. There are no postictal sympttoms.

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9
Q

What are tonic/clonic seizures?

A

ONLY occurs in generalised seizures. Combination of increase in muscle tone and jerky movements. There is a massive surge of electrical activity with cerebral neurons all firing at once, that can cause loss of consciousness and a loss of bladder control.

This is the most severe type of seizure because there may be an inability to breath due to high muscle tone. If it lasts 5 mins or more, it is status epilepticus, a medical emergency.

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10
Q

What is display automatism?

A

Performing simple or complex movements without awareness, that occurs in focal non-motor seizures in the temporal lobe.

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11
Q

What are the post-ictal symptoms for tonic-clonic seizures?

A

Aphasia, fatigue, unresponsiveness.

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12
Q

What is a focal seizures?

A

Occurs in only one region of the brain in one cerebral hemisphere and includes:

Motor which includes tonic, clonic, atonic and myoclonic and hyperkinetic.

Non-motor regions of the brain are affected which includes cognitive impairment, sensory, emotional and behaviour arrest

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13
Q

What is a partial seizure?

A

Another term for focal seizure.

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14
Q

What is a non-motor focal seizure?

A

Affect any specific regions of the brain excluding the motor cortex, ranging from vision loss to behaviour change.

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15
Q

What are the acquired causes of epilepsy?

A

Head trauma
Brain infections like encephalitis, HIV, meningitis and malaria.
Hypoxia in pregnancy
Developmental conditions like autism and epilepsy

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16
Q

What are the genetic causes of epilepsy?

A

Genetic predisposition

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17
Q

What is the presentation of parietal lobe seizures?

A

Most rare form of epilepsy which causes sensory disturbances with paraesthesia such as pins and needles.

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18
Q

What is the presentation of frontal lobe seizures?

A

Commonly occurs during sleep; It can affect language expression and motor functions like bladder and bowel control. Causes hyperkinetic movements.

Signs: facial twitch, expression of fear and unilateral facial droop.

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19
Q

What is the presentation of temporal lobe seizures?

A

It is the most common focal epilepsy which causes loss of memory, affects olfactory sensation and result in emotional disproportional disturbances like excessive fear.

There is display automatism, where simple actions are performed without intention like lip smacking. Can result in secondary generalised seizures.

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20
Q

How can epilepsy be distinguished from migraine or transient ischaemic attack?

A

Epilepsy attacks last only 20 mins, with Positive symptoms of epilepsy present initially for only a few minutes, with remaining time for negative symptoms. POSITIVE AND NEGATIVE

Transient ischaemia presents with negative symptoms that are consistent for a long duration.

Migraines present with fluctuations in either positive OR negative symptoms for a long duration.

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21
Q

What is the presentation of occipital seizures?

A

Multicoloured visual symptoms confined to a hemifield and are circular or unformed.

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22
Q

What is important when taking an epilepsy history?

A

Circumstances around the attack, separate eye witness account
Symptoms prior to the attack
Recovery time
Symptoms during the attack such as incontinence, cyanosis or injury

23
Q

What is the nature of epilepsy attacks?

A

Short duration with multiple seizures and are not situational.

24
Q

What is syncope?

A

Sudden loss of consciousness due to a reduction in cerebral perfusion. It can be associated with:
Migraine
Narcolepsy
Stroke

25
Q

What are the triggers for epileptic seizures?

A

Sleep deprivation
Stress
Alcohol/drug intake
Hormonal imbalance

26
Q

What are the investigations for epilepsy?

A

Investigations are used to support epilepsy diagnosis but cannot be used as a stand-alone confirmation:

->Blood test to assess general health and rule out triggers for seizures such as low blood sugar

->EEG can be used to confirm diagnosis for epilepsy and shows spikes during absence/petit mal seizures, but it has a high false negative rate. It is useful for identifiying seizure types, such as photosensitivity.

->CT/MRI scans

If these are negative, diagnosis can still be made based on symptoms.

27
Q

What is the treatment for generalised epilepsy?

A

Sodium valproate
Lamotrigine
Topiramate

28
Q

What is lamotrigine?

A

Anti-convulsant drug which targets voltage gated Na+ channels for glutamate and aspartate release.

29
Q

What is the treatment for partial seizures?

A

Sodium valproate
Carbamazepine
Lamotrigine

30
Q

What is the treatment for absence seizures?

A

Ethosuximide which inhibits T-type calcium ion channels.

31
Q

What are the surgical options for epilepsy?

A

Vagus nerve stimulation
Focal cortical resection

32
Q

What is VNS?

A

Vagus nerve stimulation, via an electrode attached to the neck which sends electrical impulses to the brain which reduces the number of seizures.

33
Q

What is focal cortical resection?

A

Removing damaged brain tissue which causes seizures.

34
Q

What are the excitatory neurotransmitters?

A

Glutamate which acts on NMDA receptors for calcium release.

35
Q

What are the types of syncope?

A

Orthostatic syncope
Vasovagal syncope
Carotid sinus syncope
Cardiac failure such as arrhythmias or atrial fibrillations which can cause low blood pressure.

36
Q

What is vasovagal syncope?

A

Caused by a trigger which results in a sudden drop in blood pressure such as:
Orthostatic vasovagal syncope triggered by standing up too quickly
Emotional vasovagal syncope triggered by intense emotions like fear or stress

37
Q

What is carotid sinus syncope?

A

Caused by an overreaction of the carotid sinus located in the bifurcation of the common carotid artery to pressure applied such as turning your head or looking upwards.

38
Q

What is situational syncope?

A

Vasovagal syncope caused by defaecation, coughing and mictrutition.

39
Q

What is Orthostatic syncope?

A

Caused by conditions with induce low blood pressure such as
Volume depletion due to haemorrhage, diarrhoea and vomiting

Primary autonomic failure such as old age and Parkinson’s
Secondary autonomic failure such as diabetes, amyloidosis and spinal cord injuries
Drug induced from anti-diuretics, vasodilators and anti-depressants.

40
Q

What are the triggers for seizures?

A

Excessive physical exertion
Sleep deprivation
Loud music
Strobe light
Fever
Increased intracerebral pressure and oedema
Infection
Intoxication with drugs
Drug withdrawal

41
Q

What is the postictal state?

A

The period after the seizure and when the patient returns to baseline. There are residual neurological symptoms

42
Q

What is the ictal phase?

A

Time period from the first symptom to the end of seizure activity. There is a sudden onset and progression of symptoms, with this phase lasting only 1-3 minutes.

43
Q

What is the ictal phase?

A

Period from first seizure to end of seizure activity.

44
Q

What is acute symptomatic seizure?

A

Seizure that occurs within 1 week of a brain injury, associated with electrolyte disturbances and hyperglycaemia, intoxication and CNS infection.

45
Q

What is non-epileptic attack disorder?

A

Seizures that occur due to physical causes such as hypoglycaemia and cardiac issues.
-> has no link to electrical activity.

46
Q

What is the most common cause of epilepsy?

A

Crytopgenic= Idiopathic

47
Q

What are the triggers for epilepsy?

A

VITAMINS:
V: Vascular disease/malformation
I: Infection
T: Toxins
A: Autoimmune
M: Multiple Sclerosis
I: Idiopathic
N: Neoplasm
S: Stress

48
Q

What is the action of glutamate?

A

It is an excitatory neurotransmitter which is released from pre-synaptic neurons by the opening f two channels: voltage gated Na+ channels and the influx of Na+ triggers voltage-gated Ca2+ channels to open and this triggers the exocytosis of glutamate vesicles.

Glutamate acts on NMDA and AMPA receptors on post-synaptic neurons for excitatory action.

49
Q

What is the NMDA receptor?

A

Glutamate acts on this receptor for the influx of Ca2+. Glycine is a co-agonist that binds following glutamate binding to increase ion channel opening for further Ca2+ influx.

50
Q

What is the AMPA receptor?

A

Glutamate acts on this to cause influx of Na+.

51
Q

How is GABA formed?

A

Breakdown of glutamate -> GABA by glutamate decarboxylase.

52
Q

What is the action of glycine?

A

It is an inhibitory neurotransmitter in the CNS and spinal cord, which regulates muscle

53
Q

Which anti-epileptic drug is given for pregnancy?

A

Phenytoin
Lamotrigine