EPILEPSY Flashcards
Define convulsion
Sudden attack of involuntary muscular contractions and relaxations
define seizure
Abnormal central nervous system electrical activity.
define epilepsy
A group of recurrent disorders of cerebral function characterised by both seizures and convulsions
epilepsy is usually present in childhood and adolescent.TRUE OR FALSE
TRUE
Epilepsy may occur for the first time at any age. TRUE OR FALSE
TRUE
how many percentage suffer a single seizure at some time
5%
how many percentage have recurrent seizures= epilepsy
0.5 - 1%
how many percentage is well controlled with drugs (prolonged remissions)
70%
how many percentage of epilepsy at least partially resistant to drug treatments = INTRACTABLE (pharmaco-resistant) EPILEPSY
30%
seizure is not usually life threatening.
TRUE OR FLASE
TRUE
The brain almost always stops the seizure on its own
true or false
True
What happens to a person breathing during a seizure
Breathing cease for a few seconds
patient turns blue
Do people feel pain during a seizure
No but sore muscles afterward
person may feel disorientated for a while after seizure
TRUE OR FALSE
TRUE
list the two broad classifications of seizures and how many subtypes they have
focal seizures also called partial seizures
( 3 subtypes)
Generalised seizures
( 6 subtypes)
Define focal (partial) seizures
Excessive electrical activity in one cerebral hemisphere > Affects only part of the body.
List the subtypes of focal ( partial ) seizures
simple partial
complex partial
secondary generalised
Explain simple partial seizure
Patients has sudden clonic jerking of one extremity lasting 60-90 seconds.
Patients is completely aware of the attack and can describe it in detail > Key feature: preservation of consciousness.
Explain complex partial seizure
Localised onset, but discharge can spread
Loss of awareness at seizure onset > Impairment of consciousness, although consciousness is not fully lost
Typically originate in frontal or temporal lobes (e.g. Temporal lobe epilepsy) > Difficult to treat with drugs > surgical resection.
Explain complex partial seizure
Localised onset, but discharge can spread
Loss of awareness at seizure onset > Impairment of consciousness, although consciousness is not fully lost
Typically originate in frontal or temporal lobes (e.g. Temporal lobe epilepsy) > Difficult to treat with drugs > surgical resection.
explain secondary generalised seizure
Focal seizures > generalised Seizures.
Often preceded by an AURA or warning sign > the senses of taste, smell or vision are heightened,
Define generalised seizures
Excessive electrical activity in both cerebral hemispheres.
Usually originates in the thalamus or brainstem.
Affects the whole body.
Loss of consciousness is common.
list the subtypes of generalised seizures
Myoclonic
Atonic
Tonic
clonic
tonic clonic ( grand mal)
Absence seizure(petit mal)
Status epilepticus
define myoclonic gen. seizures
Brief shock-like muscle jerks generalized or restricted to part of one extremity.
define atonic gen. seizure
Sudden loss of muscle tone.
define tonic gen. seizures
sudden stiffening of the body, arms, or legs
define clonic gen. seizures
rhythmic jerking movements of the arms and legs without a tonic component
define tonic clonic ( grand mal) gen. seizures
The most dramatic of all Tonic phase followed by clonic phase
define absences ( Petit mal) gen. seizure
Rapid and brief loss of consciousness
More common in young children.
Can include the blinking of the eyelids or lip movements
define status epilepticus
A seizure lasting longer than 30 min, or 3 seizures without a normal period in between
May be fatal
Emergency intervention required
list epilepsy syndromes
West syndrome (infantile spasms)
Lennox–Gastaut syndrome
juvenile myoclonic epilepsy
Doose syndrome
Dravet syndrome
Benign neonatal convulsions
Temporal lobe epilepsy.
Doctors classify a patient’s seizures by seizure type and then attempt to assign them to a syndrome. TRUE OR FALSE
TRUE
The broad classifications of seizures is based upon the nature of the seizures rather than presence or absence of underlying cause. TRUE or FALSE
TRUE
In 19th century neurologist Hughlings Jackson classified epilepsy as….
a sudden excessive disorderly discharge of CEREBRAL neurons
what is the recent neurobiology of epilepsy
a central role for the excitatory neurotransmiter glutamate (increased in epilepsy)
inhibitory gamma amino butyric acid (GABA) (decreased)
refer back to slide 13, 14 & 15
list causes of epilepsy
Genetic (autosomal dominant genes)
Congenital defects
Severe head trauma
Ischemic injury, tumor
Drug abuse
Unknown ( the highest percentage - 65%)
explain Anti epileptic drug
is a drug which decreases the frequency and/or severity of seizures in people with epilepsy
Treats the symptom of seizures, not the underlying epileptic condition
Does not prevent the development of epilepsy in individuals who have acquired a risk for seizures (e.g., after head trauma, stroke, tumour)
Majority of patients respond to drug therapy (anticonvulsants).
Intractable cases > surgery may be necessary.
what is the goal of anti epileptic drug therapy
Goal of therapy > maximise quality of life by eliminating seizures (or diminish seizure frequency) while minimising adverse drug effects
The Mechanisms of Action of AEDs fall into three large categories, What are they?
Inhibition of voltage-gated Na+ channels to slow neuron firing.
Enhancement of the inhibitory effects of the neurotransmitter GABA.
Inhibition of calcium channels.
LIST the AEDs
phenytoin
carbamazepine
sodium valproate Ethosuximide
gabapentin
Lamotrigine
Tiagabine
Levetiracetam
Topiramate
Vigabatrin
explain phenytoin, including MOAs
it is the oldest (1938) non-sedative AED
Effective in many forms of epilepsy - but not in absence seizures.
Highly bound to plasma proteins (about 90%) > non-linear relationship between dose and plasma concentration is non-linear.> extreme variations in plasma concentration > toxic effects > therapeutic drug monitoring essential
Mechanism of action (MOA)
Use-dependent block of sodium ion channels
Prolongs their inactive state > prevents further action potential generation
Reduces the synaptic release of glutamate and enhances the release of GABA
list side effects of phenytoin
Nystagamus (involuntary and jerky repetitive movements of the eyeballs) > occur early in treatment
Gingival hyperplasia > increase in the size of the gingiva (gums)
Hirsutism > excessive body hair
Diplopia > double vision (dose related)
Ataxia > lack of voluntary coordination of muscle movements (dose related)
Sedation > dose related
foetal abnormalities when taken by the mother during pregnancy
explain carbamazepine
Structurally related to tricyclic antidepressants
Similar profile to that of phenytoin, but with fewer unwanted side-effects.
Long considered drug of choice for partial and generalised seizure, but is be superseded by newer agents
Effective in many forms of epilepsy - but not in absence seizures.
Also useful in Trigeminal Neuralgia and Mania
Oxycarbazine > structurally and functionally related to carbamazepine
explain carbamazepine MOAs
Similar to phenytoin
Blocks sodium channels
Decreases neurotransmitter release
list the side effect of carbamazepine
sedation,
ataxia,
mental disturbances,
water retention.
explain Sodium Valproate
Chemically unrelated to other anticonvulsants.
Effective in all forms of epilepsy, but drug of choice in treatment of Absences Seizures.
Relatively few side effects
Teratogenic!
explain sodium valproate MAOs
Suppress repetitive neuronal firing through inhibition of voltage-sensitive sodium ion channels
Suppresses thalamic excitability by inhibiting transient low threshold calcium ion channels
Enhances GABA in CNS by inhibiting the catabolic enzyme GABA transaminase.
list side effects of sodium valproate
alopecia (hair loss)
and liver damage (rare but serious).
explain gabapentin
Effective in the treatment of Partial Seizures.
Relatively few unwanted side effects
explain gabapentin MOAs
Blocks glutamate stimulated Ca ion channels.
Inhibits depolarisation-induced calcium influx at nerve terminals > decreased glutamate release.
list side effects of gabapentin
nausea
and sedation.
explain Lamotrigine
Used in the treatment of Partial Seizures and Tonic –Clonic and Absences Seizures
Relatively few unwanted side effects
explain lamotrigine MAOs
Inhibits release of glutamate.
Suppress repetitive neuronal firing by inhibition of voltage-sensitive sodium ion channels
list side effects of lamotrigine
nausea, sedation, ataxia and skin rashes.
explain Tiagabine
Used in the treatment of Partial Seizures
Relatively few unwanted side effects
explain tiagabine MOAs
Inhibits the GABA transporter responsible for removing extracellular levels of GABA
Increased levels of GABA in synapses
Increased inhibitory transmission
list side effects of tiagabine
nausea, sedation and ataxia.
explain Levetiracetam
Mainly used in partial seizures
Explain levetiracetam MOAs
Binds to synaptic vesicular protein SV2A > alters synaptic neurotransmitter release
list side effects of levetiracetam
Somnolence > sleepiness
Asthenia > abnormal physical
weakness or lack of energy
Dizziness
explain Topiramate
Monosaccharide structure > different from all other AEDs
Effective against partial and generalised tonic-clonic seizures and absence seizures
Broad effectiveness against a range of epilepsy syndromes (Lennox Gastaut; West’s syndrome
Also approved for migraine headaches
well tolerated Side effects
explain topiramate MOAs
Blocks voltage-gated sodium channels
Potentiates the effects of GABA > similar to benzodiazepines, but has distinct binding site on GABAA receptors
Depresses excitatory effect of kainate on glutamate receptors
list the side effects of topiramate
Somnolence,
fatigue,
dizziness,
paraesthesia,
nervousness,
confusion
Acute myopia (near-sightedness)
and glaucoma, rare, but requires immediate withdrawal
explain vigabatrin
Useful in the treatment of partial seizures
explain vigabatrin MOAs
Irreversible inhibitor of the enzyme GABA aminotransferase > enzyme that degrades GABA
Increased levels of GABA released at synaptic sites
Enhanced neuronal inhibition
list the side effects of vigabatrin
Well tolerated generally
Drowsiness
Dizziness
Weight gain
formulations of cannabinoids are extremely useful widely in the treatment of epilepsy. TRUE OR FALSE
TRUE
explain cannabidiol
major components of the Cannabis sativa plant
No psychoactive properties, unlike tetrahydrocannabinol (THC)
Cannabidiol can be synthesized (synthetic CBD) as well as extracted from C. sativa (plant derived).
Pharmaceutical-grade CBD approval by FDA and the European Medicines Agency
> treatment of seizures in Dravet syndrome and Lennox–Gastaut syndrome
WHAT IS FOCAL SEIZURE ALTERNATIVE FIRST LINE treatment
levetiracetam, oxcarbazepine,
sodium valproate
WHAT IS FOCAL SEIZURE FIRST LINE TREATMENT
carbamazepine,
lamotrigine
what is the caution of focal seizure alternative first line treatment
be aware of potential effect of sodium valproate in pregnancy
what is the adjunctive treatment of focal seizure if first line is not effective or tolerated
carbamazepine,
clobazam,
gabapentin,
lamotrigine,
levetiracetam, oxcarbazepine,
sodium valproate, topiramate
what is the action if adjunctive treatment is not effective or tolerated
consider referral to tertiary epilepsy services (where other AEDs may be tried)
First line treatment of gen. tonic clonic seizure
sodium valproate, lamotrigine (if sodium valproate is not suitable)
what is the caution of gen tonic clonic seizure first line treatment
be aware of potential effect of sodium valproate in pregnancy. If the person has myoclonic seizures or may have juvenile myoclonic epilepsy lamotrigine may worsen myoclonic seizures
what is the alternative first line treatment of gen. tonic clonic seizure
carbamazepine, oxcarbazepine
what is the caution alternative first line treatment of gen. tonic clonic seizure
be aware that these drugs may worsen myoclonic or absence seizures
what is adjunctive treatment (if first line treatment is not effective or not tolerated):
lamotrigine,
levetiracetam,
sodium valproate, topiramate
what is caution of adjunctive treatment (if first line treatment is not effective or not tolerated)
be aware of potential effect of sodium valproate in pregnancy. If the person also has absences or myoclonic seizures, or may have juvenile myoclonic epilepsy do not offer carbamazepine, gabapentin, oxcarbazepine, phenytoin, pregabalin, tiagabine or vigabatrin
what is absence seizure first line treatment
ethosuximide,
sodium valproate (offer first if additional tonic clonic seizures are likely)
what is absence seizure caution of first line treatment
be aware of potential effect of sodium valproate in pregnancy
what is absence seizure alternative first line treatment
lamotrigine
what is absence seizure adjunctive treatment (if first line treatment is not effective or not tolerated)
consider a combination of ethosuximide, lamotrigine or sodium valproate.
what is absence seizure caution of adjunctive treatment (if first line treatment is not effective or not tolerated)
be aware of potential effect of sodium valproate in pregnancy
what is the action if adjunctive treatment is not effective or tolerated in absence seizure
consider referral to tertiary epilepsy services (where other AEDs may be tried)
what is the caution if adjunctive treatment is not effective or tolerated in absence seizure
do not offer carbamazepine, gabapentin, oxcarbazepine, phenytoin, pregabalin, tiagabine or vigabatrin
what is the first line treatment of myoclonic seizure
sodium valproate
what is the caution of first line treatment of myoclonic seizure
be aware of potential effect of sodium valproate in pregnancy
what is the alternative first line treatment of myoclonic seizure
levetiracetam,
topiramate
what is the caution of alternative first line treatment of myoclonic seizure
be aware that topiramate has poorer side effects than sodium valproate or levetiracetam
what is the adjunctive treatment (if first line treatment is not effective or not tolerated
levetiracetam,
sodium valproate, topiramate
what is the caution of adjunctive treatment (if first line treatment is not effective or not tolerated
be aware of potential effect of sodium valproate in pregnancy
what is the action if adjunctive treatment is not effective or tolerated
consider referral to tertiary epilepsy services (where other AEDs may be tried)
what is the caution if adjunctive treatment is not effective or tolerated
do not offer carbamazepine, gabapentin,
oxcarbazepine,
phenytoin,
pregabalin,
tiagabine or
vigabatrin
what is the first line treatment of tonic and atonic seizure
sodium valproate
what is the caution of first line treatment of atonic and tonic seizure
be aware of potential effect of sodium valproate in pregnancy
what is the adjunctive treatment (if first line treatment is not effective or tolerated
lamotrigine
what is the action if adjunctive treatment is not effective or not tolerated
consider referral to tertiary epilepsy services (where other AEDs may be tried)
what is the caution if adjunctive treatment is not effective or tolerated
do not offer carbamazepine, gabapentin,
oxcarbazepine,
pregabalin,
tiagabine or
vigabatrin
