Epilepsy Flashcards

1
Q

What is a seizure?

A

A sudden, irregular discharge of electrical activity in the brain causing a physical manifestation such as sensory disturbance, unconsciousness or convulsions

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2
Q

What is a convulsion?

A

Motor signs of electrical discharge.

Uncontrolled shaking movements of the body due to rapid contraction and relaxation of muscles

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3
Q

What is epilepsy?

A

A neurological disorder marked by sudden, recurrent episodes of sensory disturbance, LOC or convulsions associated with abnormal electrical activity in the brain

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4
Q

What are the two main seizure classifications?

A

Partial and generalised

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5
Q

Describe partial (focal) seizures

A

Start in a specific area on one side of the brain.

SIMPLE: consciousness maintained
- with focal motor, sensory, autonomic or psychic symptoms. No post ictal symptoms

COMPLEX: consciousness impaired

  • May have a LOC or impaired awareness or responsiveness (don’t remember having seizure)
  • Most commonly arise from temporal lobe
  • Post ictal confusion is a feature
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6
Q

What symptoms are common in a temporal lobe seizure?

A
Feeling of deja vu
Jamais vu - feeling of unfamiliarity 
Automatisms- complex motor phenomena with impaired awareness, vary from: lip smacking, chewing, swallowing or manual movements such as fiddling or grabbing, to complex actions 
Dysphasia 
Emotional disturbance- sudden terror, panic, anger, elation 
Hallucinations of smell, taste, sound 
Delusional behaviour 
Bizarre associations
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7
Q

What are secondary generalised seizures?

A

In 2/3 of patients with partial seizures, the electrical disturbance that starts focally spreads widely -> generalised seizure

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8
Q

Describe generalised seizures

A

Originate at some point within then rapidly distribute bilaterally leading to widespread electrical discharge with no localising features.

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9
Q

What types of generalised seizures are there?

A
Tonic clonic
Tonic
Myoclonic 
Atonic 
Absence
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10
Q

Describe a tonic clonic seizure

A
Muscle tense (tonic) then jerk (clonic) 
Described as rhythmic jerking
Tonic phase:
- 10 to 60 sec 
- rigid, epileptic cry, tongue biting, incontinence, hypoxia/cyanosis (no breathing in this phase) 

Clonic phase:

  • jerking
  • eye rolling, tachycardia, random breathing

Often aura before
Afterwards post ictal state - confused, drowsy, headache, some enter coma

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11
Q

What is a tonic seizure

A

When the muscles increase in tone

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12
Q

What is a myoclonic seizure?

A

Sudden jerk of limb, face or trunk - shock like.

Patient may be thrown to ground or violently disobedient limb

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13
Q

What is an atonic seizure?

A

Sudden loss of muscle tone - drop attack

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14
Q

What is an absence seizure?

A

Brief < 10 second pauses, stop and carry on as if nothing happened
Unresponsive to stimuli but conscious
Patient stares, may go pale

Complete recovery without post ictal confusion or headache

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15
Q

When do absence seizures present?

A

In childhood
Likely to develop tonic clonic later in life
40% have relatives with epilepsy

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16
Q

Some patients experience a preceding prodrome before having a seizure. What is this characterised by?

A

Change in mood or behaviour

Can last from hours to days

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17
Q

Epilepsy most commonly occurs in isolation, but certain conditions are associated with it such as…

A

Cerebral palsy - 30% have epilepsy
Tuberous sclerosis
Mitochondrial diseases

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18
Q

When do febrile convulsions typically occur?

A

In children between 6 months and 5 years

Early in a viral infection as temperature rises rapidly

Typically brief and generalised tonic of tonic-clonic

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19
Q

What is an aura?

A

A focal awareness seizure that can precede another seizure type.

Usually occurs a few minutes before.
Sensory disturbances

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20
Q

An aura can mean what symptoms ?

A
Feeling of deja vu 
Flashing lights
Strange smell or taste
Numbness or tingling 
Strange feeling in the gut

Can be any sensation

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21
Q

What can happen during a seizure?

A

Tongue biting

Incontinence

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22
Q

What can happen post ictally?

A
Confusion 
Headache 
Nausea
Fatigue 
Myalgia 

Weakness after focal seizure in motor cortex (Todd’s palsy)
Dysphasia after focal seizure in temporal lobe

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23
Q

In those with epilepsy, the seizure threshold is said to be…

A

Lowered - neurons are hyperexcitable

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24
Q

What triggers can push neuron excitation past the seizure threshold?

A

Sleep deprivation
Alcohol - intake and withdrawal
Drug misuse
Flickering lights
CNS Infection
Metabolic disturbance e.g hypoglycaemia, hypoxia, thyroid dysfunction, electrolyte imbalance e.g hypocalcaemia
Less common: loud noises, hot bath, strange smells and sounds

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25
Q

All people who have had a seizure should be referred to a neurologist and seen within how many weeks?

A

2 weeks

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26
Q

How is epilepsy diagnosed?

A

Thorough history - collateral important
Establish type
Rule out provoking causes - most people would have a seizure given sufficient provocation, but not classified as epileptic

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27
Q

What investigations should be done?

A
EEG - not to diagnose, but can support it
ECG - cardiac cause of syncope
MRI - structural lesions 
Drug screen 
LP if infection suspected 
Bloods
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28
Q

Until diagnosis known, what should be avoided?

A

Swimming
Heights
Driving

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29
Q

How long should driving be stopped for after having seizure?

A

First unprovoked/ isolated seizure : 6 months off if no structural abnormalities on imaging and no definite epileptiform activity on ECG
If these conditions not met this is increased to 12 months

If established epilepsy or multiple unprovoked seizures - may qualify for driving licence if free from seizure for 12 months

Withdrawal of epilepsy medication-should not drive for 6 months after last dose

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30
Q

When should anti epileptic drugs be commenced?

A

Most neurologists start AEDs following second epileptic seizure
NICE suggests starting them after first seizure if:
- a neurological deficit
- brain imaging shows structural abnormality
- EEG show unequivocal epileptic activity
- patient of family consider risk of having further seizure unacceptable

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31
Q

What are some differentials?

A
Vascular: stroke
Infection: abscess, meningitis
Trauma: intracerebral haemorrhage 
Autoimmune: SLE 
Metabolic: hypoxia, electrolyte imbalance, hypoglycaemia, thyroid dysfunction 
Iatrogenic: drugs, alcohol 
Neoplastic: intracerebral mass
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32
Q

If seizure is due to mediation change, how long can patient not drive for?

A

Need to be 6 months seizure free

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33
Q

What drug is first line for generalised seizures?

A

Sodium valproate

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34
Q

What are the side effects of sodium valproate?

A
Teratogenic 
Nausea is common - take with food 
Liver failure - monitor LFTs
Pancreatitis 
Hair loss
Oedema 
Ataxia 
Tremor 
Thrombocytopenia 
P450 enzyme inhibitor
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35
Q

What is the first line treatment for focal seizures?

A

Carbamazepine

Binds to sodium channels to increase refractory period

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36
Q

Carbamazepine may exacerbate what types of generalised seizures?

A

Myoclonic

Absence

37
Q

What are the side effects of carbamazepine?

A
Dizziness
Ataxia 
Drowsiness
Visual disturbance - especially diplopia 
Leukopenia 
Mild generalised erythematous rash
SIADH 

P450 enzyme inducer e.g warfarin more rapidly metabolised and hormone contraception

38
Q

When can lamotrigine be used?

A

First line instead of SV for tonic clonic, tonic or atonic

Can be used instead of carbamazepine for partial

39
Q

What are the side effects of lamotrigine?

A

Maculopapular rash - in rare cases SJS or TEN

Visual disturbance
Tremor
Agitation
Vomiting

40
Q

When can levetiracetam be used?

A

Second line for focal, tonic clonic and myoclonic

41
Q

What are the side effects of levetiracetam?

A

Psychiatric side effects common - depression, agitation
D&V
Drowsiness

42
Q

Why is phenytoin no longer first line?

A

Due to toxicity and side effect profile

43
Q

Over how many months should the dose of AEDs be built up?

A

2 to 3 months

44
Q

When switching drug what approach should be taken?

A

Introduce new drug slowly and only withdraw first once established on second

45
Q

Epilepsy carries what percentage risk of fetal abnormalities?

A

5% - good seizure control prior to conception and during pregnancy is vital

46
Q

What should be avoided in pregnancy?

A

Sodium valproate
Polytherapy

And avoid prior to conception

47
Q

What is the preferred AED in pregnancy?

A

Lamotrigine

48
Q

What advice should be given to women of child bearing age?

A

Take folic acid 5mg/d

49
Q

What AEDs are present in breast milk?

A

Most except carbamazepine and valproate

Lamotrigine not thought to be harmful to infants

50
Q

Which AEDs are liver enzyme inducing?

A

Carbamazepine
Phenytoin
Barbiturates

51
Q

Enzyme inducing AEDs make which type of contraception unreliable?

A

Progesterone only

52
Q

What is status epilepticus?

A

Seizure lasting more than 5 minutes or recurrent without regaining consciousness

53
Q

Prolonged seizure activity can lead to what?

A

Irreversible brain damage

54
Q

How should status epilepticus be managed?

A

Secure airway
Give oxygen
IV bolus lorazepam 4mg, 2nd dose if no response after 10 to 20 minutes
(Buccal midazolam if no IV access or rectal diazepam if not available)
If seizure continues start phenytoin infusion (not if bradycardia or heart block)

55
Q

What percentage of cases have no identifiable cause?

A

70%

56
Q

When does it normally present?

A

Childhood/teenage years

57
Q

What percentage have a first degree relative with epilepsy?

A

30%

58
Q

What can cause seizures?

A
Genetic component 
Trauma
Cortical scarring e.g head injury years before 
Space occupying lesion 
Raised ICP 
Alcohol and benzodiazepine withdrawal
Vascular abnormalities eg stroke 
Metabolic disturbance e.g hypoxia, low calcium, hyper/hypoglycaemia, uraemia, liver disease
Infection - meningitis, encephalitis 
Drugs - tricyclics, cocaine
59
Q

Describe a simple partial seizure

A

Patient remains conscious
Isolated limb jerking common
May be isolated head turning - away from side of seizure
May be isolated paraesthesia (there can be any isolated motor or sensory sign)
Weakness of the limbs may follow = Todd’s paralysis

60
Q

What may indicate pseudo seizures (psychogenic non-epileptic seizures)?

A

Gradual onset
Prolonged duration and abrupt termination
Closed eyes +/- resistance to eye opening
Rapid breathing
Fluctuating motor activity
Episodes of motionless unresponsiveness

CNS examination normal, CT, MRI and EEG all normal
May have history of mental health problems or a personality disorder

61
Q

What features indicate a frontal lobe focal seizure?

A
Motor symptoms- posturing, peddling movements of legs 
Jacksonian march 
Motor arrest 
Dysphasia or speech arrest 
Post ictal Todd’s palsy
62
Q

What features suggest a parietal lobe focal seizure?

A

Sensory disturbances - tingling, numbness, pain (rare)

Motor symptoms due to spread to pre central gyrus

63
Q

What features occur in an occipital local focal seizure?

A

Visual phenomena- spots, lines, flashes

64
Q

What is a Jacksonian march?

A

A spreading focal motor seizure with retained awareness

Starting with face or a thumb, ipsilateral spread

65
Q

What can be done as an adjunct to medication?

A

Psychological therapies - relaxation, CBT

66
Q

When could surgical intervention be considered?

A

If single epileptogenic focus identified e.g in hippocampal sclerosis or small low grade tumour

Vagus nerve stimulation
Deep brain stimulation

67
Q

Sudden unexpected death in epilepsy is more common in…

A

Uncontrolled epilepsy

May be related to nocturnal seizure associated apnoea or asystole

68
Q

Oestrogen containing contraceptives lower what AED levels?

A

Lamotrigine - an increased dose may be required to achieve seizure control

69
Q

What mnemonic can be used for cytochrome P450 inducers?

A
CRAPS our drugs 
Carbamazepine 
Rifampin 
bArbituates 
Phenytoin 
St Johns wort
70
Q

What mnemonic can be used for cytochrome P450 inhibitors?

A

Some Certain Silly Compounds Annoyingly Inhibit Enzymes, Grrrrrr

Sodium valproate 
Ciprofloxacin
Sulphonamide 
Cimetidine/omeprazole
Antifungals, amiodarone 
Isoniazid
Erythromycin 
Grapefruit juice
71
Q

How does sodium valproate work?

A

Increased GABA activity - an inhibitory neurotransmitter

Inhibits sodium channels

72
Q

How does carbamazepine work?

A

Binds to sodium channels increasing their refractory period

73
Q

How does lamotrigine work?

A

Sodium channel blocker, thus reducing action potential propagation

74
Q

How does phenytoin work?

A

Binds to sodium channels increasing their refractory period

75
Q

What are some side effects of phenytoin?

A

Toxicity: nystagmus, diplopia, tremor, dysarthria, ataxia
Later: confusion, seizures

Side effects:
Reduced intellect 
Depression
Coarse facial features
Gingival hyperplasia
Hirsutism 
Peripheral neuropathy 
Blood dyscrasias - megaloblastic anaemia (due to altered folate metabolism) 
Osteomalacia - enhanced vit D metabolism 
Lymphadenopathy 

Blood levels required for dosage (narrow therapeutic window)

76
Q

When can ethosuximide be used?

A

Can be used instead of SV for absence seizures

77
Q

What is the main excitatory neurotransmitter in the brain?

A

Glutamate

78
Q

What receptor does glutamate act on and what affect does it have?

A

Acts on NMDA receptors - causes calcium influx (tells the cell to send signals)

Some with epilepsy may have fast or long lasting activation of these receptors

79
Q

When can AEDs be stopped?

A

If seizure free for more than 2 years with AEDs being stopped over 2-3 months

80
Q

What features suggest temporal lobe involvement?

A

HEAD
Hallucinations - auditory, olfactory, gustatory
Epigastric rising/emotional
Automatisms - lip smacking, grabbing, chewing
Deja vu/jamais vu /dysphasia

81
Q

Do patients typically outgrow absence seizures?

A

One third of patients outgrow them, one third continue to have simple absence and one third go on to occasional concomitant generalized tonic-clonic seizures

82
Q

What is another term for absence seizures?

A

Petit mal (old term)

83
Q

What is topiramate used for?

A

Second line for generalised tonic clonic and myoclonic

84
Q

What are the side effects of topiramate?

A
Nausea 
Drowsiness and dizziness 
Diarrhoea
Depression 
Loss of appetite, weight loss 
Hair loss
Increased ammonia leading to encephalopathy or kidney stones 
Blurred vision, eye pain - glaucoma
85
Q

When is phenobarbitone used?

A

Seizures in young children

The injectable form may be used for status epilepticus

86
Q

What are the side effects of phenobarbital?

A
Decreased level of consciousness
Decreased respiratory effort 
Dizziness
Ataxia 
Nystagmus
87
Q

How does phenobarbital work?

A

Increases the activity of the inhibitory neurotransmitter GABA

88
Q

Is phenobarbital a CYP450 inhibitor or inducer?

A

Inducer

It can be used to reduce the toxicity of some drugs

89
Q

Oestrogen containing contraceptives lower… levels, so an increased dose may be needed to achieve seizure control

A

Lamotrigine