Epilepsy 3 Flashcards
Why does the presentation of generalised epilepsy usually occur in childhood & adolescence ?
Because it is usually due to a genetic predisposition
What are the 5 main types of generalised epilepsy ?
Think juan MATTA
- Absence seizures
- Tonic-clonic seizures
- Myoclonic seizures
- Atonic seizures
- Tonic seizures
Describe the typical presentation of a absence seizure
- Person becomes blank & unresponsive for a few seconds (<10secs)
- May appear to be day dreaming, they usually stop what they are doing & look blank, they will not respond to what is happening around them
- May carry on walking etc but will not be aware they are.
- This has a characteristic 2.5-3.5 Hz spike & wave pattern
May be associated with mild clonic jerking of the eyelids & extremities
Describe the typical presentation of tonic-clonic seizures (grand-mal)
This is the seizure that most people think of as epilepsy
There is major convulsions with rigidity (tonic) & jerking (clonic) which slows over 60-120 seconds followed by a stuporous state (post-ictal depression) e.g. confusion, headache, sleepiness
2 main phases:
- Tonic phase - muscles suddenly tense up, causing the person to fall to the ground if they are standing
- Clonic phase - muscles will start to contract & relax rapidly, causing convulsions
What are the 2 non-convulsive generalised epilepsies ?
Atonic and absence seizures
Describe the typical presentation of myoclonic seizures
- Sudden jerk of a limb, face or trunk
- Person may be thrown to the ground by the jerk, or have a violently disobedient limb
- They are brief but can happen in clusters (many happening close together)
- Often happen shortly after waking
- Risks for causing them include - flashing lights, alcohol, sleep deprivation (often can happenin freshers week) would be known as juvenile myoclonic epilepsy at a young age
Describe the typical presentation of atonic seizures
- Sudden loss of muscle tone causing a fall, no loss of consciousness
- Tend to be brief and recover quickly
Describe the typical presentation of tonic seizures
- Muscles suddenly become stiff, if standing often fall
- Tend to be brief without warning & recover quickly
What is the 1st line treatment of focal seizures ?
1st line = Carbamazepine or lamotrigine (go with lamotrigine due to less side effects)
2nd line = Levetriacetum, oxycarbazepine or sodium valproate
What is the 1st & 2nd line treatment of atonic, tonic and generalised tonic-clonic seizures and state the problem with the 1st line treatment?
(just think that all the ones with the word tonic in them have the same treatment)
- 1st line = sodium valproate
- 2nd line = lamotrigine
The problem with sodium valproate is that it is teratogenic so cannot be given to women of childbearing age
What is the treatment of absence seizures ?
- 1st line = sodium valproate, then if this doesn’t work then ethosuximide
- 2nd line = lamotrigine
What is the treatment of myoclonic seizures ?
- 1st line = sodium valproate
- 2nd line = Levetiracetum
- 3rd line = topiramate
What are the 4 main targets which different AED’s act on ?
- Increase inhibitory neurotransmitter system - GABA
- Decreased excitatory neurotransmitter system - Glutamate
- Block voltage-gated inward positive currents - Na+ or Ca2+
- Increase outward positive current K+
What is the mechanism of action of sodium valproate ?
Works by enhancing GABA synthesis
What are the main side effects of sodium valproate ?
- Weight gain
- Teratogenic
- Hair loss
- Fatigue
Think - what the hell fiona
What is the mechanism of action of carbamazepine ?
Inhibit voltage gated Na+ channels
What are the side effects of carbamazepine and why do you need to be cautious when using it ?
- Sedation
- Ataxia
- Mental disturbances
- Water retention
Need to be careful when usnig it because it can make generalised epilepsies worse
Think - sorry at my wedding
What is the mechanism of action of Lamotrigine ?
It inhibits voltage-gated Na+ channels
What are the main side effects of lamotrigine ?
Hypersensitivity reaction esp skin rashes (hence so not much incomparison to carbamazepine)
When is phenytoin used in the treatment of epilepsy ?
Only used in the acute management i.e. status epilepticus, as rapid loading dose possible
What is the mechanism of action of phenytoin ?
Inhibits voltage-gated Na+ channels
What are the side effects of phenytoin ?
Confusion, gum hyperplasia, skin rashes, anaemia, teratogenesis, cerebellar syndrome, osteoporosis
What is the mechanism of action of Levetiracetum and its main side effect?
Acts by binding to SV2A, interfering with synaptic vesicles & inhibiting neurotransmitter release
It can cause mood swings
What is the mechanism of action of Topiramate and its main side effects
- Mechanism of action = Enhances response of GABAA receptors to GABA
- SE - sedation, dysphagia, weight loss, cognitive problems
What is the mechanism of action of ethosuximide and its main side effects?
- It inhibits voltage-gated Ca2+ channels
- May cause nausea & anorexia
What is the mechanism of action of gabapentin and pregabalin ?
- Inhibit voltage-gated Ca2+ channels
- They are more used for neuropathic pain
