Epilepsy Flashcards

1
Q

What factors should be considered when making a possible diagnosis of epilepsy

A
history from patient and witness
aura/ warning 
abnormal movements
colour
position 
when 
after effects 

what are the signs? what is the type of seizure?

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2
Q

what investigations should be done when making an epilepsy diagnosis

A

examination will often be normal

EEG, ECG, MRI

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3
Q

what is the difference between a partial and generalised seizure

A

partial seizure activity originates in one area of the brain and may be simple or complex

generalised seizures affect the whole brain(both hemispheres) and may be absent, myoclonic, tonic clonic, tonic, atonic

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4
Q

what are the features of a myoclonic seizure

A

a type of generalised seizure

the person is usually awake
brief shock like jerks of muscles

seen in a wide variety of seizures

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5
Q

what are the features of simple partial seizures

A

focal with minimal spread of abnormal discharge

normal consciousness

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6
Q

what are the features of complex partial seizures

A
local onset then spreads
impaired consciousness
often an aura
automatisms 
motor activity 

most commonly temporal lobe epilepsy

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7
Q

what are secondary generalised seizures

A

begin focally, with or without focal neurological symptoms
variable symmetry, intensity and duration of tonic-clonic phases

usually 1-2 minutes
postictal confusion and somnolence

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8
Q

what are the features of absence seizures

A
a type of generalised seizures 
sudden onset and abrupt cessation 
brief duration 
altered consciousness
may be mild clonic jerking 
postural tone change 
autonomic features and automatisms
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9
Q

what is an atonic seizure

A

sudden loss of postural tone

often in children

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10
Q

what are the features of tonic clonic seizures

A

major convulsions with rigidity (tonic) and jerking (clonic)

followed by stuporous state- post ictal depression

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11
Q

what are the phases of generalised tonic clonic seizures

A

1) tonic phase, muscles tense up causing the person to fall to the ground
2) Muscles start to contract and relax rapidly- clonic phase

may also occur in partial seizures involving motor centres

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12
Q

what factors increase seizure risk

A
lack of sleep 
tiredness
alcohol/ hangover
certain drugs e.g. antidepressants 
fever 
structural brain abnormalities
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13
Q

what is status epilepticus

A

more than 30 minutes of seizure activity or multiple seizures in 30 minutes without full recovery in between

medical emergency

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14
Q

In what proportion of epileptics are medications effective at reducing seizure

A

60% become seizure free

20% are drastically reduced

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15
Q

what AEDs act primarily on sodium channels

A

phenytoin, carbamazepine, oxcarbazepine, zonisamide, lamotrigine

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16
Q

what is a partial seizure

A

confined to one lobe or hemisphere of the brain

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17
Q

what is a simple partial seizure

A

person remains conscious

may involve strange sensations or abnormal movements

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18
Q

what is a complex partial seizure

A

local onset, then spreads
impaired consciousness
aura
automatisms

person looses consciousness or regains consciousness slowly

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19
Q

what are the types of generalized seizures

A
absence
myoclonic
tonic 
clonic
tonic clonic
atonic
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20
Q

what are the types of partial seizure

A

simple partial

complex partial

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21
Q

what are the features of absence seizures

A

sudden onset and abrupt
cessation; brief duration, consciousness is altered; attack
may be associated with mild clonic jerking of the eyelids or
extremities, postural tone changes, autonomic phenomena
and automatisms (difficult diagnosis from partial);
characteristic 2.5-3.5 Hz spike-and wave pattern

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22
Q

what is a myoclonic seizure

A

myoclonic jerking is seen in a wide
variety of seizures but when this is the major seizure type it
is treated differently to some extent from partial leading to
generalized

23
Q

what seizures are non convulsive

A

atonic and absence

24
Q

what seizures may convulsions be seen in

A

simple and complex partial

generalised seizure

25
what is the function of antiepileptic drugs
treats the frequency and severity of seizures they cannot stop the cause of seizures
26
what are the cellular mechanisms of seizure generation
EPSPs sodium influx calcium currents paroxysmal depolarization
27
what are the cellular mechanisms of seizure control
``` IPSPs potassium efflux chloride influx pumps low pH ```
28
what are the targets for AEDs
increase inhibitory nt system -GABA decrease excitatory NT system- glutamate block voltage gated inwards positive currents of sodium or calcium increase outward positive current of potassium many are pleitropic
29
what is glutamate
major excitatory NT
30
what are the two types of glutamate receptors
ionotropic (fast synaptic transmission) metabotropic (slow) regulation of second messengers
31
What AEDs act primarily on sodium channels
phenytoin carbamazepine oxcarbazepine zonisamide lamotrigine
32
what are the current commonly used epilepsy drugs
``` lamotrigine sodium valproate carbamazepine oxcarbazepine levetiracetam topiramate ```
33
what are some older less used drugs
* phenytoin, * ethosuxamide, * phenobarbitone, * vigabatrin, * tiagabine
34
lamotrigine
inhibits sodium channels broad therapeutic profile side effect: skin rashes
35
sodium valproate
increase in GABA content side effects: teratogenicity liver damage
36
carbamazepine
tricyclic antidepressant derivative used in partial seizures and trigeminal neuralgia enzyme inducing agent so drug interactions side effects: sedation, ataxia
37
oxcarbazepine
related to carbamazepine partial seizures sedating but less toxic
38
levetiracetam
inhibits Ca partial and general seizures psychiatric side effects
39
topiramate
not well understood | teratogenesis
40
tiagabine
gaba uptake inhibitor | partial seizures
41
zonisamide
blocks sodium channels
42
phenytoin
blocks sodium channels not effective in absence seizures common drug interactions and side effects :confusion, gum hyperplasia, skin rashes, anaemia, teratogenesis, cerebellar syndrome, osteoporosis also an antidysrhythmic
43
ethosuximide
absence seizures in children blocks calcium channels few side effects
44
phenobarbitone
rare long half life osteoporosis
45
benzodiazepines
``` status epilecticus (IV) sedating ```
46
felbamate
unknown moa | limited to otherwise untreatable and severe disease
47
vigabatrin
inhibits GABA transaminase for pts unresponsive to other drugs, rare side effects: drowsiness, behavioural and mood changes
48
gabapentin/ pregabalin
calcium channels inhibits NT release add on therapy for partial seizures and tonic clonic less sedating than classic AEDs used in neuropathic pain
49
when is neurosurgery indicated for epilepsy
partial seizures usually when you've tried at least 3 drugs electrophysiology functional MRI
50
baclofen
agonist for GABA receptors action exerted at level of spinal cord used for spasticity from MS or spinal injury not used in epilepsy
51
what is the main difference between a simple and complex partial seizure
simple seizures do not involve a reduction or alteration in consciousness a simple partial may be an aura to a complex or generalised seizure
52
what is NMDA
a glutamate receptor which allows positively charged ions to flow into the cell
53
what is the treatment for status epilepticus
diazepam, lorazapam IV phenytoin, fosphenytoin or phenobarbitol
54
what epilepsy drugs are commonly used in children
valproate lamotrigine levetricetam ethosuxamide