Epilepsy Flashcards
What is the most common neurological disorder?
Epilepsy
How common is epilepsy and what is it characterised by? How common are seizures?
1:20 will have a seizure at some point in their lifetime whereas 1:103 will have epilepsy. Epilepsy is characterised by recurrent seizures.
What are the two main categories of epilepsy? How is epilepsy diagnosed?
Focal and generalised. Epilepsy is diagnosed mainly by symptoms recounted by the individual/ witnesses and by EEG/MRI/CT scan.
Who characterises Epileptic type seizures? How are the categories broken down?
International league against epilepsy (ILAE).
Categories are broken down into either focal, focal to generalised (focal to bilateral tonic clonic), generalised, unknown (often seizures during the night), or unclassified.
Focal is further broken down into either aware or impaired awareness. Then broken down by symptoms - either motor or non-motor.
Generalised broken down into motor vs non motor.
Describe the characteristics/ auras of a temporal seizure
- Temporal lobe houses limbic system (memory and emotion), including hippocampus and amygdala. Also responsible for integration of taste sensation, smell, understanding speech (Wernicke’s) and hearing.
- Auras: changes in taste/ smell, deja vu, jamais vu (never seen before)
- Seizures -> Oral automatisms (unconcious behaviours), including fidgeting and dystonia (sustained muscle contractions resulting in abnormal positioning/ tremor).
Describe the characteristics of a frontal lobe seizure
- Frontal lobe –> primary motor cortex, supplementary motor area and pre motor cortex.
- Motor seizures –> brief, frequent, can cluster
- Tend to be bilateral, present with kicking/ cycling movements, violent and bizarre
- head torsion can occur
- often occur after waking from sleep
Describe the characteristics/ auras of parietal seizures
- Parietal lobe –> primary somatosensory cortex, therefore sensory seizures
- Sensory seizures present with –> tingling sensation/ warmth
- Auras: nausea, choking, sinking sensation, illusion of body distortion
Describe the characteristics/ auras involved in occipital seizures
- Occipital lobe —> primary visual cortex and visual association areas
- Auras –> visual hallucinations (simple - flashing lights) or complex (scenes).
- Vision may black out
- visuo- spatial distortions
- head turning, headache and nausea.
What are the two types of focal seizure?
Describe the characteristics of both types
-
Focal aware (used to be called partial simple).
- Characterised by no loss of awareness
- no post ictal confusion
- symptoms depend on the lobe affected
- tends to affect the temporal lobe (region of high plasticity which is prone to over excitation).
-
Focal w impaired awareness (used to be called partial complex).
- Characterised by altered conciousness (but may seem fully aware)
- may have post ictal confusion
- Prior to concioussness change may have auras
- Common symptom –> automatism (Chewing, swallowing, repeated displacement)
- again commonly in temporal region
What is a jacksonian seizure?
What group of seizures does it fall into?
What types of jacksonian seizure are there?
- A jacksonian seizure is a type of focal aware seizure that describes a seizure in which symptoms migrate from one region of the body to another, normally from distal to proximal following HAL (hand/arm/leg) pattern. Up through arms down through body.
- Focal Aware motor –> Jacksonian motor seizure –> affecting motor cortex
- Short lasting, ripple of muscle activity
- may be localised to one group of muscles or progress
- progression distal to proximal through limbs and trunk, following from hanfs up arms to trunk down legs
- Focal Aware sensory –> Jacksonian sensory seizure –> affects primary somatosensory cortex
- short lasting sensory changes
- may be localised to one area or progress
- usually distal to proximal
- through limbs and trunk (Following HAL).
What are the characteristics of a focal to bilateral tonic clonic seizure?
- Characteristics: focal that progresses to a generalised (tonic/ clonic or grand mal seizure).
- Due to activation of connecting pathways or the thalamus
- As it starts focal the patient can experience auras prior to onset
- can have unilateral motor effects but most often are bilateral (activation of commisural fibres).
- (note in EEG trace on bottom shows seizure starting off in the R before progressing to the L).
What is a generalised tonic clonic seizure?
What are the characteristic features of a tonic clonic seizure? (describe onset, duration, recovery)
What would their EEG trace show?
- Generalised tonic clonic seizure (used to be known as grand mal seizure) is a seizure that affects the whole brain (starts in both sides), isn’t preceeded by a warning (although patients can know their triggers) and is generally the easiest to diagnose.
- when it starts in one side of the brain and spreads this is focal to bilateral tonic clonic seizure
- usually lasts 1-3 minutes, more than 5 minutes is a medical emergency
- Characterised by a tonic phase followed by a clonic phase.
- Tonic phase –>
- increase in tone of muscles, sudden stiffening, loss of conciousness, fall to the ground
- Air can rush past vocal cords –> scream as they fall
- may bite on their tongue
- Clonic phase –>
- sudden rythymic contractions of muscles in arms and legs
- altered breathing and cyanosis
- During recovery phase patient will slowly regain conciousness and muscles will start to relax.
- Could also be: loss of bladder/ bowel control as their body relaxes, confusion, no recollection of episode, drowsy, headaches, aching limbs
- EEG tract will show large amplitude deflections, affecting both hemispheres and synchrony. Rythmic activity shown –> thought gap junctions could be involved.
What is generalised absence?
- Generalised abscence is a seizure in which the person is said to become blanked out/ switched off/ stare into space but cannot be alerted or woken up.
- Most commonly affects children (6-12 yrs) and rarely affects adults
- affects girls more than boys
- Responds very well to anti epileptic drugs
What is status epilepticus?
- Status epilepticus is a medical emergency, where there is generalised tonic clonic activity affecting the whole brain for a prolonged period of time (greater than 5 mins) or repeatedly without recovery (longer than 30 mins)
- Either ictal period > 5 mins
- or repeated seizure without recovery
- or repeated seizures for 30 mins
- Always treated as a medical emergency as prolonged seizuring can cause permanent brain damage
- Other forms of status epilepticus are long lasting, absence or focal type seizures.
Outline 4 other forms of seizures (not including focal aware/ w impaired awareness/ Jacksonian/ absence/ generalised tonic clonic/ status epilepticus).
- Generalised myoclonic –> sudden shock like jerks of groups of muscles, (like falling asleep), possibly familial
- Generalised clonic –> repeated muscle twitches and jerks w/ no stiffness
- Generalised tonic –> all muscles contract, whole body stiffens
- Generalised atonic –> “drop attacks”, muscle tone lost, head/ body become limp.
What is NEAD?
What is its other name?
How is it diagnosed?
What are the differences between NEAD and generalised tonic clonic?
How does this affect treatment?
- NEAD = non epileptic attack disorder
- Also known as psychogenic seizures
- Seizures that mimick generalised tonic clonic seizures exactly but there seems no be no physical reason or any changes in brain activity
- Diagnosis requires EEG
- May be slight differences to generalised tonic clonic in:
- duration (may last seconds to 2-3 mins)
- eye opening - eyes firmly shut in NEAD vs open in generalised
- tongue biting - tip of tongue in NEAD vs lateral tongue generalised
- Recollection - NEAD can recollect
- Treatment not with antiepileptics but with antidepressants, antianxiety and psychological
What is the pharmacological treatment for focal and focal –> generalised seizures?
- 1st line :
- Carbs, marzipan, lamb and terrine, pro salt eating can lead to focal seizures that become generalised.
- Carbmazepine
- Lamotrigine
- Sodium valproate
- 2nd line/ adjuncts:
- Clobazam
- Topiramate
- gabapentin
Describe the treatment for status epilepticus
- Basic life support- open and secure airway, 100% oxygen
- IV access- take bloods look for U&E, FBC, Glucose, Ca2+, toxicology screen if indicated, anticonvulsant levels
- IV lorazepam (or iv diazepam) - repeat if no response within 10 minutes- must have resucitation facilities available as risk of respiratory arrest
- Or if in community/ no resusc facilities available –> buccal midazolam or rectal diazepam
- No response within 25 mins –> IV infusion barbiturates –> phenytoin or phenobarbital
- No response within 45 mins —> Anaesthetise –> used barbiturates -Thiopental, non barbiturate –> propofol or benzodiazepine –> midazolam
Name the barbiturate drugs used in epilepsy treatment
What is their mechanism of action?
How does this aid epilepsy treatment?
- Phenobarbitone
- Pentobarbitone
- Primidone
- Mechanism of action –> binds at a binding site between alpha/ beta subunits of GABA receptor –> +ve allosteric modulator
- Aids in treatment of epilepsy as it enhances inhibitory GABA signalling which reduces neuronal transmission.
What are other GABA modulating drugs that act on uptake and transport?
- Inhibiting the GABA transporter –> Tiagabine
- Inhibiting GABA breakdown –> inhibit GABA transaminase –> vigabatrin
