10. Seizures - epileptic, non-epileptic, syncope Flashcards
Give 5 causes of transient loss of consciousness.
- Syncope.
- Epileptic seizures.
- Non-epileptic seizures.
- Intoxication e.g. alcohol.
- Ketoacidosis/hypoglycaemia.
- Trauma.
Define syncope.
Insufficient blood or oxygen supply to the brain causes paroxysmal changes in behaviour, sensation and cognitive processes.
Give 5 signs that a transient loss of consciousness is due to syncope.
- Situational.
- 5-30s in duration.
- Sweating.
- Nausea.
- Pallor.
- Dehydration.
Define seizure.
A convulsion caused by paroxysmal discharge of cerebral neurones.
Abnormal and excessive excitability of neurones.
Give a definition for a non-epileptic seizure.
Mental processes associated with psychological distress cause paroxysmal changes in behaviour, sensation and cognitive processes.
List 4 non-epileptic causes of seizures.
- Trauma
- Stroke
- Haemorrhage
- Raised ICP
- Alcohol/benzodiazepine withdrawal
- Metabolic disturbance
- Liver disease
- Fever
- Infection - HIV, meningitis, encephalitis, syphilis
- Drugs - tricyclics, cocaine, tramadol, theophylline
Give 5 signs of a non-epileptic seizure.
- Situational.
- 1-20 minutes in duration (longer than epileptic).
- Eyes closed.
- Crying (ictal) or speaking.
- Pelvic thrusting.
- History of psychiatric illness.
- Very fast or very slow post-ictal recovery.
- No cyanosis, tongue biting, incontinence or injury.
What is epilepsy?
The tendency to have seizures.
Give a definition for an epileptic seizure.
Excessive, unsynchronised neuronal discharges in the brain cause paroxysmal changes in behaviour, sensation or cognitive processes.
At what age does epilepsy usually develop?
Before 20 or over 65
Which is likely to last for longer, an epileptic or a non-epileptic seizure?
A non-epileptic seizure can last from 1-20 minutes whereas an epileptic seizure lasts for 30-120 seconds.
Give 5 causes of epilepsy.
- 2/3rds are idiopathic often familial
- Cortical scarring:
* Head injury years before onset
* Cerebrovascular disease e.g. cerebral infraction, haemorrhage or stroke
* CNS infection e.g. meningitis or encephalitis - Space-occupying lesion e.g. tumour
- Tuberous sclerosis
- Alzheimer’s or dementia - epilepsy more common
- Alcohol withdrawal
What are the 3 main elements of a seizure?
- Prodrome
- Precedes the seizures (usually hrs or days before)
- Not part of the seizure, results in change of mood or behaviour
- People with tonic-clonic seizures more likely to have this - Aura
- Part of seizure where the patient is aware and may precede its
other manifestations
- E.G. strange feeling in gut, déjà vu, strange smells, flashing lights
- Often implies a partial focal seizure, but not necessarily from the
temporal lobe - Post-itcal
- The period after the seizure
- Headache, confusion, myalgia and a sore tongue (often bitten)
- Temporary weakness after a focal seizure in motor cortex - Todd’s palsy
- Dysphagia following temporal lobe focal seizure
Give 5 signs/features of an epileptic seizure.
- 30-120s in duration.
- ‘Positive’ symptoms e.g. tingling and movement.
- Tongue biting (lateral)
- Head turning (positive ictal symptoms)
- Muscle pain.
What 2 categories can epileptic seizures be broadly divided into?
- Primary/Generalised epilepsy - the whole brain is affected.
- Partial/Focal epilepsy - only one portion of the brain is involved.
What are primary/generalised epileptic seizures?
- Simultaneous onset of electrical discharge throughout whole cortex (involving both hemispheres), with no localising features referable to only one hemisphere
- Bilateral symmetrical and synchronous motor manifestations
- Always associated with loss of consciousness or awareness
Give 3 examples of generalised epileptic seizures.
- Generalised tonic-clonic seizures (AKA grand-mal)
- Typical absence seizure (aka petit mal)
- Myoclonic seizure
- Tonic seizure
- Atonic (akinetic) seizure
What occurs in the brain during a primary generalised seizure?
Simultaneous onset of electrical discharge throughout cortex with no localised features.
What do the terms tonic, myoclonic and akinetic mean in terms of seizures?
Tonic = intense stiffening of body with no convulsions.
Myoclonic = isolated muscle jerking (rapid repetitions of this = clonic).
Akinetic = cessation of movement, falling and loss of consciousness.
Describe the features of generalised tonic-clonic seizures
- Often no aura
- Loss of consciousness
- Tonic phase (muscle tensing):
* Rigid, stiff limbs - person will fall to floor if standing - Clonic phase (muscle jerking):
* Generalised, bilateral, rhythmic muscles jerking lasting sec-mins - Eyes remain open and tongue often bitten
- There may be incontinence of urine/faeces
- Post-ictal -> drowsiness, confusion or coma for several hours
Describe the features of absence seizures.
- Usually a disorder of childhood
- Child ceases activity, stares and pales for a few seconds only (brief pauses):
I.e. suddenly stops talking in mid-sentence, then carries on where left-off - Often do not realise that they’ve had an attack
- On EEG characterised by a 3-Hz spike and wave activity
- Children with petit mal tend to develop generalised tonic-clonic
seizures in adult life
Describe the features of myoclonic seizures.
- Sudden isolated jerk of a limb, face or trunk
(Isolated muscle jerking) - Patent may be thrown suddenly to the ground, or have a violently disobedient limb
Describe the features of tonic seizures.
- Sudden sustained increased tone with a characteristic cry/grunt.
- Intense stiffening of body (tonic).
- Stiffening NOT FOLLOWED by jerking.
Describe the features of atonic (akinetic) seizures.
‘Drop attack’
- Sudden loss of muscle tone and cessation of movement, resulting in a fall.
- Muscles go floppy - NO loss of consciousness.
What are partial/focal epileptic seizures?
- Focal onset, with features referable to a part of 1 hemisphere e.g. temporal lobe
- Often seen with underlying structural disease
- Electrical discharge is restricted to a limited part of the cortex of 1 cerebral hemisphere
- These may later become generalised (e.g. secondarily generalised tonic-clonic seizures)
Do partial seizures impair consciousness?
Some do -> partial complex - do not know you are having a seizure
e.g.psychomotor (automatisms)
Some don’t -> partial simple - myoclonic, Jacksonian
Give 3 examples of focal epileptic seizures.
- Simple partial seizures with consciousness.
- Complex partial seizures without consciousness.
- Secondary generalised seizures.
Describe the features of simple partial seizures.
- Not affecting consciousness or memory
- Awareness is unimpaired with focal motor, sensory (olfactory,
visual etc.), autonomic or psychic symptoms - No post-ictal symptoms
Describe the features of complex partial seizures.
- Impaired awareness
-> Affecting awareness or memory before, during or immediately
after the seizure. - Most commonly arise from the temporal lobe
–> Understanding speech, memory & emotion - Post-ictal confusion is common with seizures arising from the
temporal lobe, whereas recovery is rapid after seizures in the
frontal lobe (thought processing & movement).
Describe the features of partial seizures with secondary generalisation.
In 2/3rds of patients with partial seizures:
-> The electrical disturbance, which starts focally (as either a simple or complex partial seizure), SPREADS WIDELY:
-> causing a secondary generalised seizure, which is typically convulsive.
I.E. Begins in 1 part of the brain and spreads to both sides.
List some features of a focal seizure that would localise it to the temporal lobe.
- Temporal lobe (memory, emotion & speech understanding):
- Aura (80%) - Deja-vu, auditory hallucinations, funny smells, fear
- Hippocampal involvement = emotional disturbance
- Uncal involvement = smell/taste hallucinations
- Auditory cortex involvement = auditory hallucinations - Anxiety or out of body experience, automatisms (motor phenomena with impaired awareness + no recollection afterwards)
e.g. lip smacking, chewing, fumbling, fiddling
List some features of a focal seizure that would localise it to the frontal lobe.
- Frontal lobe (motor and thought processing):
1. Motor features - e.g posturing, peddling movements of the leg, versive movements of head and eyes
- Jacksonian march
-> Seizure “marches” up or down the motor homunculus -> starting in face or thumb - Post-ictal Todd’s palsy
-> Paralysis of limbs involved in seizure for several hours
List some features of a focal seizure that would localise it to the parietal lobe.
- Parietal lobe (interprets sensations):
- Sensory disturbances - tingling/numbness - parasthesia
- Motor symptoms - spread to pre-central gyrus.
List some features of a focal seizure that would localise it to the occipital lobe.
- Occipital lobe (vision):
- Visual phenomena e.g. spots, lines or flashes
How to differentiate between epilepsy and syncope?
- Epilepsy rather than syncope:
- Tongue biting, head turning, muscle pain, loss of consciousness,
cyanosis, post-ictal symptoms - Syncope rather than epilepsy:
- Syncope is the loss of consciousness due to hypo-perfusion to brain
- Prolonged upright position e.g. long time standing, sweat prior to loss of consciousness, nausea, pre-syncopal symptoms
Investigations to diagnose epilepsy.
A diagnosis of epilepsy is made by a specialist based on the characteristics of the seizure episodes.
- EEG
- Not diagnostic
- Performed to support diagnosis of epilepsy when history suggests it
- May help determine seizure type and what epilepsy syndrome
- Frequently it is normal between attacks and false-positive may be detected in non-epileptics
- Typically a 3Hz spike and wave is seen in a Absence seizure of the temporal lobe - MRI:
* With imaging of the hippocampus is used to study epilepsy - CT head:
* Used in emergency to look for space occupying lesion e.g. tumour
* Also used to identify or exclude structural abnormalities that could be causing symptoms - Blood tests:
* FBC, electrolytes, Ca2+, renal function, liver function, urine
biochemistry and blood glucose levels
* Done to rule out metabolic causes and discover comorbidities - Genetic testing e.g. in juvenile myoclonic epilepsy
What is the diagnostic criteria for epilepsy?
1 of the following:
- At least 2 unprovoked seizures more than 24 hours apart
- One unprovoked seizure and a probability of future seizures (considered >60% risk in 10yrs)
- Diagnosis of an epilepsy syndrome
Compare non-epileptic seizures to epileptic seizures.
Comparing non-epileptic seizure to epileptic seizure:
- Non-epileptic seizures are situational.
- Non-epileptic is longer, closed mouth/eyes during tonic-clonic movements, pelvic thrusting, do not result from sleep, no incontinence or tongue biting.
- There are pre-ictal anxiety symptoms in non-epileptic seizure.
What is status epilepticus?
Status epilepticus is an important condition you need to be aware of and how to treat. It is a medical emergency. It is defined as seizures lasting more than 5 minutes or more than 3 seizures in one hour.
Treatment of epilepsy in an emergency - status epilepticus.
- Emergency measures:
1. Ensure patient harm themselves as little as possible - ABCDE approach
- Secure the airway
- Give high-concentration oxygen
- Assess cardiac and respiratory function
- Check blood glucose levels
- Gain intravenous access (insert a cannula)
- IV lorazepam 4mg, repeated after 10 minutes if the seizure continues
- If seizures persist: IV phenobarbital or IV phenytoin loading
- If still fitting -> then anaesthetist involvement for anaesthetic and ventilation
Once epilepsy is confirmed (and sure its not syncope or non-epileptic seizure), decide whether is partial or generalised seizures.
Treatment of epileptic seizures.
Generalised tonic-clonic seizures:
1st line -> sodium valproate
2nd line -> lamotrigine or carbamazepine
Focal seizures:
1st line -> carbamazepine or lamotrigine
2nd line -> sodium valproate or levetiracetam
Absence seizures:
1st line -> sodium valproate or ethosuximide
Atonic seizures:
1st line -> Sodium valproate
2nd line -> lamotrigine
Myoclonic seizures:
1st line -> sodium valproate
Other options: lamotrigine, levetiracetam or topiramate
General pathway for treatment:
1. Anticonvulsant monotherapy (1st line)
2. Alternate anti-convulsant monotherapy (2nd line)
3. Dual anti-convulsant therapy (3rd line)
4. Surgery - 4th line
How does sodium valproate work?
It works by increasing the activity of GABA, which has a relaxing effect on the brain.
Give 2 side effects of oral sodium valproate.
S/E:
1. Weight gain
2. Hair loss
3. Liver failure + hepatitis
What is the main contraindication of sodium valproate?
Teratogenic:
So patients need careful advice about contraception
It must be avoided in girls or women unless there are no suitable alternatives and strict criteria are met to ensure they do not get pregnant.
Give 2 side effects of carbamazapine.
S/E:
1. Diplopia (double vision)
2. Rashes
3. Leucopenia (reduction in white cells)
4. Impaired balance
5. Drowsiness
6. Agranulocytosis
7. Aplastic anaemia
-> Induces the P450 system so there are many drug interactions
Give 2 side effects of Lamotrigine.
S/E:
1. Maculopapular rash
- Stevens-Johnson syndrome or DRESS syndrome
(These are life threatening skin rashes.)
2. Blurred vision
3. Vomiting
4. Leukopenia
Give 2 side effects of ethosuximide.
- Night terrors
- Rashes
Give 2 side effects of phenytoin.
- Folate and vitamin D deficiency
- Megaloblastic anaemia (folate deficiency)
- Osteomalacia (vitamin D deficiency)
If pharmacological treatment does not work at all, what is the next step in treatment?
Neurosurgical treatment - if drugs not working:
- If a single defined cause is identified such as hippocampal sclerosis or low grade tumour:
-> then SURGICAL RESECTION can offer 70% chance of seizure freedom. - Alternative is VAGAL NERVE STIMULATION, which can reduce seizure frequency and severity in 33%.
Differential diagnosis of epilepsy.
- Postural syncope
- Cardiac arrhythmia
- TIA
- Migraine
- Hyperventilation
- Hypoglycaemia
- Panic attacks
- Non-epileptic seizure
What are febrile seizures?
Seizures that occur in children whilst they have a fever:
-> only occur in children ages 6 months - 5 years.
Causes:
- They are not caused by epilepsy or other underlying neurological pathology (meningitis or tumours).
- Febrile convulsions do not usually cause any lasting damage.
- Having febrile convulsions slightly increases the risk of developing epilepsy in the future.
What are infantile spasms?
AKA West Syndrome.
- A rare disorder
- 1 in 4000
- Starting in infancy at around 6 months
- Characterised by clusters of full body spasms
- Poor prognosis:
- 1/3 die by age 25
- 1/3 are seizure free
- Difficult to treat but first line treatment is:
- Prenisolone
- Vigabatrin
A patient complains of having a seizure. An eye-witness account tells you that the patient had their eyes closed, was speaking and there was waxing/waning/pelvic thrusting. They say the seizure lasted for about 5 minutes. Is this likely to be an epileptic or a non-epileptic seizure?
This is likely to be a non-epileptic seizure.
A patient complains of having a seizure. An eye-witness account tells you that the patient was moving their head and biting their tongue. They say the seizure lasted for just under a minute. Is this likely to be an epileptic or a non-epileptic seizure?
This is likely to be an epileptic seizure.
A patient complains of having a ‘black out’. They tell you that before the ‘black out’ they felt nauseous and were sweating. They tell you that their friends all said they looked very pale. Is this likely to be due to a problem with blood circulation or a disturbance of brain function?
This is likely to be due to a blood circulation problem e.g. syncope.
