Epilepsy Flashcards
What are the main categories of epilepsy?
Focal
Generalised
Unknown
What is a focal aware seizure?
No loss of consciousness or post-ictal confusion
Symptoms dependent on focal site - commonly temporal lobe (due to plasticity leading to over-excitation)
What are the signs and symptoms of a seizure originating in the frontal lobe?
Motor seizures - often bilateral
Including kicking, cycling, violent movements
What are the signs and symptoms of a seizure originating in the parietal lobe?
Sensory (e.g. tingling or warm sensation)
Auras (e.g. nausea, sinking, choking, body distortion)
What are the signs and symptoms of a seizure originating in the occipital lobe?
Visual hallucinations (can be simple or complex) Black outs Visuo-spatial distortion Headache Nausea
What is non-epileptic attack disorder (NEAD)?
Characterised by similar symptoms to a tonic-clonic seizure however with no physical reason/ change in electrical activity in brain
What are Jacksonian seizures?
Short-lasting rippling effect as activity passes over cortical region.
Can be motor or sensory.
What is a generalised tonic clonic seizure?
No warning of onset
Tonic phase can involve whole body stiffness, cyanosis, loss of bladder control
Clonic phase involves muscle jerks
Post-ictal phase can include unconsciousness, muscle relaxation, slow regain of consciousness, headaches, aching limbs, no recall of episode
What is a generalised absence?
Low level activity
Individual appears to ‘switch off’ and can not be alerted or woken up
More common in girls and tends to be most common in children (onset age 6-12)
What is a status epilepticus?
Generalised tonic clonic activity
Ictal period of more than 5 minutes OR repeated seizures with no recovery between for more than 30 minutes
MEDICAL EMERGENCY
What are the sub-types of generalised seizure according to the ILAE?
Motor or non-motor (absent) seizures
What are the characteristics of a focal to bilateral tonic clonic seizure?
Focal seizure progressing to a generalised seizure as activity from the thalamus projects to other regions.
Can experience auras prior to onset.
Can have unilateral motor effects.
How is status epilepticus classified?
Prolonged seizure state
ICD-10, G41
What is a generalised myoclonic seizure?
Sudden jerk movements
What is a generalised clonic seizure?
Repeated twitches and jerks (with no stiffness)
What is a generalised tonic seizure?
Whole body stiffness
What is a generalised atonic seizure?
Loss of muscle tone
‘Drop attacks’
Quick recovery
How can NEAD be diagnosed?
Video EEG
How does non-epileptic attack disorder appear on EEG?
Normal brain activity
What are the advantages of EEG?
Useful for investigating gross cortical activity
Non-invasive/ painless
Can be used over long periods of time (e.g. video EEG)
Cost effective
What is the aetiology of seizures?
Reduced GABAergic transmission and K+ channel activity
Increased ACh transmission and Na+ channel activity
Channelopathies - mutations in K+, Na+, ACh and GABA receptors linked to congenital forms of seizures
What are the signs and symptoms of a seizure originating in the temporal lobe?
Auras
Deja vu/ Jamais vu
Emotional changes
Oral automatisms
What are the differences between epileptic seizures and a NEAD seizure?
Eyes: open (epileptic) vs closed (psychogenic/ NEAD)
Memory: no memory (epileptic) vs memory of seizure (NEAD)
How can EEG be used to diagnose epileptic seizures?
Determines type through distinct patterns and pinpointing focal activity (and progression of seizure throughout brain)
What are EEGs recording?
Changes in gross current flow
Levels of synchrony between neurons causes changes in patterns (firing together causes larger amplitude oscillations)
What brain waves can be seen on EEG?
Alpha Beta Gamma Theta Delta
How are alpha waves characterised?
8-13 Hz
Mainly occipital activity
Eyes shut/ meditation
How are beta waves characterised?
> 14 Hz
Parietal and frontal activity
Slow wave sleep
How are gamma waves characterised?
40 Hz
Learning and memory
How are theta waves characterised?
4-7 Hz
Parietal and temporal activity
Alertness, learning and memory
How are delta waves characterised?
<3.5 Hz
Cortical activity
Deep sleep or coma
What are the treatment options for epilepsy?
Pharmacological (AEDs)
Surgical
Implants (VNS/ DBS)
What is the best treatment for non-epileptic seizures?
CBT
Antidepressants or antipsychotics
What are the disadvantages of surgical treatment for epilepsy?
Scar tissue can cause seizures
What are the pharmacological options for treating epilepsy (focal/ focal to generalised/ generalised tonic clonic)?
Lamotrigine
Carbamazepine
Sodium Valproate
When should sodium valproate not be used?
Women of child-bearing age (due to teratogenicity causing birth defects)
What drug can be used only to treat absent seizures?
Ethosuximide
What is the emergency treatment for status epilepticus?
- IV Lorazepam/ Diazepam or Buccal Midazolam (in resusc)
- Phenobarbital sodium (after 25 mins)
- Anaesthetise (after 45 minutes)
What can be used instead of IV medication to treat status epilepticus (e.g. oustide of resusc)?
Buccal Midazolam
Rectal Diazepam
What is the first line treatment for generalised myoclonic seizures?
Sodium valproate
What types of seizures tend to respond poorly to typical AEDs?
Generalised absence atypical
Generalised atonic
Generalised tonic
What is antiepileptic hypersensitivity syndrome?
Major side effects of AEDs including fever, rash and swollen lymph nodes (typical onset = 1-8 weeks from treatment initiation)
What should you do in the case of Antiepileptic Hypersensitivity Syndrome?
- Withdraw treatment immediately
- Topical steroids and antihistamines
- Systemic corticosteroids (?)
- Be aware of potential rebound seizure activity
What is the mechanism of action of Sodium channel blockers?
Block voltage-dependent Na+ channels
Only block in inactivated state
Which AEDs are sodium channel blockers?
Lamotrigine
Carbamazepine
Sodium valproate
What are the potential side effects of sodium channel blockers?
CNS effects Peripheral neuropathy Skin problems Gum hyperplasia Anaemia/ blood disorders Osteomalacia (bone weakness) Teratogenicity
How do GABA targets work?
Indirectly enhance activation of GABA mediated channels via:
- action at co-agonist site
- inhibition of GABA breakdown
- inhibition of GABA uptake
- GABAmimetics
What drugs are GABA targets?
Gabapentin
Pregabalin
(both GABAmimetics)
What is the mechanism of action of Benzodiazepines?
Co-agonist of GABA receptor (gamma subunit) to increase activity
Reduces neuronal transmission by enhancing inhibition
What is the mechanism of action of Barbiturates?
Co-agonist of GABA receptor (beta subunit) to increase activity
Reduces neuronal transmission by enhancing inhibition
What are the side effects of Benzodiazepines and Barbiturates?
Tolerance/ dependency (should only be used short term)
Withdrawal
Impaired motor coordination/ decreased muscle tone
Impaired cognitive performance
Sedation
Disturbed sleep
Retrograde amnesia
What is the mechanism of action of calcium channel blockers?
Blocks voltage dependent or low threshold Ca+ channels
What are some common calcium channel blockers?
Ethosuximide
Gabapentin
[Possibly lamotrigine]
What are possible future targets that could be used to treat epilepsy?
Glutamate antagonists Gap junction inhibitors Enzymes Cannabinoids Steroids CO2
