Epilepsy/Seizure/Syncope Flashcards
Define Epilepsy
Condition in which there is a tendency to have seizures. Seizures occur when neurones in brain are synchronously active when they shouldn’t be. Usually self resolve in <3 mins and can occur during sleep.
What are the main excitatory and inhibitory neurotransmitters in the brain?
Excitatory - Glutamate which binds to NMDA receptors, which open ion channels to let calcium in.
Inhibitory - GABA which binds to GABA receptors that cause signal inhibition by opening channels that let chloride ions in.
Risk factors for Epilepsy
Cerebrovascular disease
Head trauma
Cerebral infection
Premature birth
Congenital brain malformations
Genetic predisposition/Family history
Pathophysiology of Epilepsy
Neurones in brain become impaired, sending out excitatory signals, either due to excess excitation (fast/long acting glutmate/NMDA) or reduced inhibition (GABA).
When jerking starts in a specific muscle group and spreads to other muscles as more neurones affected over time, this is called a Jacksonian March
Define focal seizure
Focal - limited to one hemisphere, or smaller area (e.g. lobe).
Focal seizures. How they happen, types and a complication
Usually start in temporal lobes, affecting hearing, speech, memory and emotions.
Simple - Patient remains conscious, no post ictal symptoms and remembers what happened
Complex - Impaired consciousness/awareness. May not remember, presents with post ictal symptoms
Can go on to become secondary generalised seizures
How does a focal seizure affecting temporal lobe present
Temporal - Aura (Deja vu, auditory hallucinations) + anxiety, mood change, seeing flashing lights
How does frontal lobe seizure present
Frontal - Motor features (peddling of leg) Jacksonian march and Todd’s palsy.
How does parietal lobe seizure present
Parietal - Paraesthesia
Presentation of occipital lobe seizure
Occipital - Visual disturbance (spots, lines, flashes)
Management of focal seizures
1st- Carbamazepine (sodium channel blocker)
2nd- lamotrigine
Stages of a seizure
- Prodromal phase (hours- days preceding) - Confusion, irritability, mood disturbance
- Early ictal/ Aura (minutes before) - Deja vu, lip smacking, rapid blinking, strange smells etc (imply temporal lobe epilepsy)
- Seizure (depends on type)
- Post ictal (confusion, drowsiness, irritability)
Symptoms of a post ictal period
- Headache
- Confusion
- Todd’s paralysis - if motor cortex affected, may have temporary paralysis and muscle weakness
- Dysphasia
- Amnesia
- Sore tongue (If tongue biting in seizure)
Define Generalised seizure
Where both hemispheres of the brain are affected. Bilateral and involve a loss of consciousness
Types of generalised seizure
Tonic - Stiff/fall backwards
Atonic - Relaxed muscles/fall forwards (<3 mins)
Clonic - Violent convulsions
Tonic-Clonic - Stiff and fall before convulsions start
Myoclonic - Short muscle twitches (face, limbs, trunk)
Absence - Impaired awareness (staring blankly into space)
What condition is associated with Atonic seizures
Lennox-Gastaut syndrome
Describe tonic-clonic seizure
AKA Grand mal
- No aura
- Loss of consciousness, tonic (stiff) phase then clonic (muscle jerking)
- Associated tongue biting, incontinence, open eyes
- Prolonged post-ictal period
Describe Absence seizures
AKA Petit mal
- Childhood, 90% recover into adulthood
- Patient stares blankly into space, before carrying on as normal
- Displays 3Hz spike on EEG
Diagnostic criteria for epilepsy
- 2 or more unprovoked seizures in 24 hours
- 1 unprovoked seizure with probability of further seizures felt to be same as those with 2+ in a day.
Other investigations in Epilepsy
EEG - 3Hz wave spike in absence seizures
CT head/MRI - Examine hippocampus, check bleeds, tumours
FBC - Determine if there is a metabolic cause
Complications of Epilepsy
Todd’s paralysis - Paralysis affecting arms or legs, usually limited to one side of body and self resolves after a few days. Usually follows frontal lobe seizure
Status epilepticus - Single, continuous seizure lasting 5+ mins or 2 more without regaining consciousness in between. Treated with benzodiazepines (diazepam)
Injury during seizure
Social stigma
Treatment of Epilepsy
Tonic-clonic, atonic, myolconic
1st - Sodium valproate first (GABA analogue)
2nd - Lamotrigine (sodium channel blocker) second
Absence
- Ethosuximide (calcium channel blocker)
Ethosuximide Indication in Epilepsy
Absence seizures
Ethosuximide side effects
Night terrors
Rashes
Ethosuximide MoA
Blocks T type Ca2+ channels of thalamic neurones, decreasing firing
Sodium valproate indication in epilepsy
1st line in generalised seizures EXCEPT in pregnancy!
Sodium valproate MoA
GABA analogue - Increases GABA activity (inhibitory neurotransmitter)
Sodium valproate side effects
Highly Teratogenic!!
Hair loss
Tremors
Lamotrigine Indication in epilepsy
Second line generalised seizures, except in pregnancy/women of child bearing age. Then first line.
Lamotrigine MoA
Na+ channel blocker and suppresses release of glutamate, reducing excitability of neurones.
Lamotrigine Side effects
Blurred vision
Leukopenia
Stevens-Johnson syndrome (life threatening rash)
Carbamazepine indication in epilepsy
Focal seizures
Carbamazepine MoA
Sodium channel blocker, reduces excitability of neurones, preventing action potentials.
Carbamazepine side effects
Agranulocytosis
Aplastic anaemia
Dizziness
Rash
How is status epilepticus treated
Benzodiazepine (IV Lorazepam) then pheytoin
What are the driving rules in epilepsy
Single seizure = stop driving 6 months
Drivers must be seizure free for 12 months before being given a licence. Seizure free for 5 years for HGV.
If medicine withdrawn, wait 6 months after medication stoppage before driving again
Define Syncope
Temporary loss of consciousness due to disruption in blood flow. Also called vasovagal episode/fainting
Pathophysiology of syncope
Vasovagal episode: Vagus nerve receives a strong stimulus (emotion, pain, temperature change), stimulating the parasympathetic nervous system, keeping smooth muscles in blood vessels constricted. As blood vessels relax, brain is hypoperfused, causing loss of consciousness.
2 other causes of syncope
Carotid sinus hypersensitivity - Mild external pressure induces fainting as reflex response
Orthostatic hypotension (drop in 20+ mmHg when person goes from lying to standing quickly)
Signs/symptoms of syncope
- Fainting secondary to exercise or going quickly from sitting/lying to standing.
- Lasts 5-30 seconds and recovery within another 30
- Presyncopal clamminess/dizziness etc but no post ictal symptoms
- Can have twitching but duration is much less
Lifestyle advice to a syncope patient
Avoid dehydration
Avoid missing meals
Avoid standing still for long periods
Sit or lie down if prodromal dizziness/clamminess/blurry vision occurs
Investigations in syncope patient
History taking
- Check features that distinguish syncope from seizure
- Triggers? /After exercise?
- Any concurrent illness/family history
- Any associated neurological or cardiac symptoms
Examination
- Head for injury
- Lying+standing blood pressure
Explain non-epileptic seizure
- Usually caused by psychosocial distress
- 1-20 mins
- Dramatic motor phenomena
- Eyes closed with ictal crying and speaking
- Usually history of psychiatric illness
Differentiating features of non epileptic seizures vs epileptic
- Seizures dont occur during sleep
- Pelvic thrusting but no incontinence, tongue biting or ictal injury
- Long duration, eyes/mouth closed
- Ictal crying and speaking
- Unusually rapid or slow recovery
Different causes of Epilepsy, NES, and syncope
Epilepsy - Hypersynchronous neuronal discharge
NES - Psychosocial stress
Syncope - Insufficient brain perfusion
Duration of seizure in epilepsy, NES, syncope
Epilepsy - <3 mins
NES - 1-20 mins
Syncope - seconds
How does a focal seizure affecting temporal lobe present
How does parietal lobe seizure present
Parietal - Paraesthesia
