Neurology: Syncope, Febrile Convulsions & Epilepsy Flashcards
What is syncope?
Temporarily losing consciousness due to a disruption of blood flow to the brain, often leading to a fall.
AKA fainting, vasovagal episodes.
What causes a vagovagal episode?
1) When the vagus nerve receives a strong stimulus (e.g. emotional event, painful sensation or change in temperature) it can stimulate the parasympathetic nervous system
2) This counteracts the sympathetic nervous system (which keeps the smooth muscles in blood vessels constricted)
3) As the blood vessels delivering blood to the brain relax, the blood pressure in the cerebral circulation drops
4) This leads to hypoperfusion of brain tissue –> “faint”.
Patients often remember the event and can recall how they felt prior to fainting –> ‘prodrome’.
What does this involve?
- hot or clammy
- sweaty
- heavy
- dizzy or lightheaded
- vision going dark or blurry
- headache
Is there a postictal period following sybcrope?
No - seizures only
Can there be incontinence in syncopal episodes?
Yes
What are some causes of primary syncope (i.e. simple fainting)?
1) dehydration
2) missed meals
3) extended standing in a warm environment e.g. school assembly
4) a vasovagal response to a stimuli, such as sudden surprise, pain or the sight of blood
What are some 2ary causes of syncope?
- Hypoglycaemia
- Dehydration
- Anaemia
- Infection
- Anaphylaxis
- Arrhythmias
- Valvular heart disease
- Hypertrophic obstructive cardiomyopathy
When taking a LOC history, it can be split into before, during & after.
What questions should you as regarding ‘before’?
1) Triggers
2) What were they doing before?
3) Prodromal symptoms e.g. nausea, tinnitus, sweating, visual disturbance, vertigo, light-headedness, palpitations, chest pain
4) Aura-like symptoms or focal motor/sensory symptoms e.g. unusual smells or tastes, visual hallucinations, deja-vu, twitching or weakness of arms/legs
5) Concurrent illness, fever or infection?
When taking a LOC history, it can be split into before, during & after.
What questions should you as regarding ‘during’?
1) Do they remember falling?
2) Was fall witnessed?
3) Did they hit their head or any other part of body?
4) Any muscle jerking, tongue biting or incontinence
5) How long did LOC last?
6) Length of lie
When taking a LOC history, it can be split into before, during & after.
What questions should you as regarding ‘after’?
1) Who found them? How did they get up/get to doctors?
2) Any confusion or drowsiness after fall?
3) How long did it take to be back to usual self?
4) Injuries, pain, head trauma?
Features common to syncopal episodes:
- Prolonged upright position before the event
- Lightheaded before the event
- Sweating before the event
- Blurring or clouding of vision before the event
- Reduced tone during the episode
- Return of consciousness shortly after falling
- No prolonged post-ictal period
Potential investigations in a fall?
1) Obs
2) Focused exams e.g. cardiac, neuro
3) Lying & standing BP
4) Head CT
5) ECG (24h ECG if paroxysmal arrhythmias are suspected)
6) Echo: if structural heart disease is suspected
7) Bloods: FBC (anaemia), U&Es (arrhythmias and seizures), glucose (diabetes)
General advice for simple vasovagal episodes?
- Avoid dehydration
- Avoid missing meals
- Avoid standing still for long periods
- When experiencing prodromal symptoms such as sweating and dizziness, sit or lie down, have some water or something to eat and wait until feeling better
What is a febrile convulsion?
A type of seizure that occurs in children with a high fever (>37.8 degrees).
They are NOT due to underlying pathology such as epilepsy, infection or tumours.
What age do febrile convulsions occur?
ONLY in children between 6 months to 5 years.
How common are febrile convulsions?
Relatively common, with around 2-5% of children experiencing at least one.
Association between febrile convulsions and epilepsy?
A small proportion of children who experience them do go on to develop epilepsy later in childhood, particularly if they have experienced more than one.
What are some causes of febrile seizures?
Any febrile illness can cause febrile seizures, but around 80% are viral.
Common causes:
- Respiratory tract infections
- Otitis media
- UTIs
- Influenza
What is a simple febrile convulsion?
Generalised tonic clonic seizures.
These last less than 15 minutes and only occur once during a single febrile illness.
What is a complex febrile convulsion?
Febrile convulsions can be described as complex when they:
1) consist of partial or focal seizures, or
2) last more than 15 minutes, or
3) occur multiple times during the same febrile illness.
Do they majority of children with febrile seizure present with a simple or complex febrile convulsion?
Simple (75%)
Clinical features of a simple febrile convulsion?
1) generalised tonic-clonic seizure: muscle stiffness and jerking or shaking of the limbs
may also have:
2) breathing difficulties
3) pallor
4) cyanosis
5) LOC
6) post-ictal period (from minutes to hours)
Clinical features of complex febrile convulsions?
Present similarly to simple febrile convuslions but:
- more focal features e.g. movement limited to only one side of the body
- last >15 mins
- recur within 24 hours or within the same illness
- post-ictal period is often prolonged
Define febrile status epilepticus
A subgroup of complex febrile seizure where the seizure lasts >30 mins (or there are multiple seizures lasting a total of 30 minutes without recovery between each one).
These are unlikely to resolve without intervention.