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.
When do febrile seizures typically occur in a febrile illness?
Typically within the first 24h of a febrile illness, though may also present later.
Note - Seizures are more commonly associated with a sudden rise in temperature, rather than the absolute height of a fever.
Important features to ask about a febrile convulsion?
1) Presence of fever:
- Onset
- Peak temperature
- Duration
2) Details of seizure:
- Characteristics
- Duration
3) Developmental history
4) Immunisation history, including any recent immunisations.
It is also important to clarify whether this is the first presentation of a seizure.
What are some differentials for a febrile convulsion?
- Epilepsy
- Meningitis, encephalitis or another neurological infection such as cerebral malaria
- Intracranial space occupying lesions, for example brain tumours or intracranial haemorrhage
- Syncopal episode
- Electrolyte abnormalities
- Trauma (always think about non accidental injury)
Typical patient presenting with a febrile seizure?
A child around 18 months of age presenting with a 2 – 5 minute tonic clonic seizure during a high fever.
The fever is usually caused by an underlying viral illness or bacterial infection such as tonsillitis.
Once a diagnosis of a febrile convulsion has been made, look for the underlying source of infection.
Important questions to remember for febrile convulsion history:
1) Has the child been vaccinated?
2) Are they currently at school?
3) Previous treatment with antimicrobials?
4) Any history of trauma or toxin ingestion?
5) Any family history?
6) Developmental history?
What is the focus of the examination after a febrile seizure?
1) ensure that the child is safe after their seizure
2) find the source of the infection.
What should your exam involve when looking for the source of infection after a febrile seizure?
1) External ear examination with auroscope: otitis externa or otitis media
2) Throat examination: signs of URTI (inflamed tonsils etc.)
3) Respiratory exam: LRTI
4) Check fontanelles
5) Brudzinski’s or Kernig’s sign: signs of meningitis, though less reliable in infants
6) Nuchal rigidity (neck stiffness)
7) Mental status of the child (irritable, playful)
8) Full neurological examination
9) CVS & abdo exam
10) Urinalysis & microscopy
11) Any superficial infective skin lesions
12) Temperature
Why is it important to check the fontanelles after a febrile convulsion?
Raised anterior fontanelles with no pulsation felt in infants can be a sign of meningitis or raised ICP
What are some red flags suggestive of CNS infection in infants?
1) Complex febrile seizures
2) Prolonged post-ictal altered consciousness or neurological deficit (lasting >1 hour)
3) Any physical signs of meningitis/encephalitis e.g. bulging fontanelle, neck stiffness, photophobia, focal neurological signs –> in children younger than 18 months, symptoms and signs of meningeal irritation, such as meningism and photophobia, may be absent
4) Previous/current treatment with antibiotics which may have masked full clinical presentation of meningitis
5) Incomplete immunisation in children 6-18 months against Haemophilus influenzae B and Streptococcus pneumoniae
Incomplete immunisation against which 2 pathogens are a risk factor for CNS infection?
1) Haemophilus influenzae B
2) Streptococcus pneumoniae
When is a urine culture indicated in febrile seizure?
if <18 months of age or complex seizure
Acute management of a febrile seizure?
1) ABCDE
2) General measures: preventing injuries by cushioning the head and removing nearby potential hazardous objects, monitor length of seizure
3) Keep the child well hydrated
4) Paracetamol or ibuprofen – helpful in reducing the temperature and distress but does not decrease recurrence
What advice can be given to parents on managing a febrile seizure if a further episode occurs?
1) Stay with child
2) Put the child in a safe place, for example on a carpeted floor with a pillow under their head
3) Place them in the recovery position and away from potential sources of injury
4) Don’t put anything in their mouth
5) Monitor length & call an ambulance if the seizure lasts more than 5 minutes
The first seizure should always result in a trip to hospital for assessment, however if parents are confident and can safely manage the child at home then they can visit their GP at the next available opportunity.
Do simple febrile convulsions require further investigations/treatment?
No - parents can be reassured and educated about the conditions
When should parents call an ambulance for a febrile seizure?
If lasts >5 mins
Management of a febrile seizure that lasts >5 mins?
Emergency benzodiazepine, then continue to follow the APLS guideline for status epilepticus.
Can give buccal midazolam or rectal diazepam
What are the risk factors for recurrent febrile seizures?
- Age at onset under 18 months.
- Shorter duration of fever before seizure (<1 hour).
- Relatively lower grade of fever associated with seizure (<40C).
- Multiple seizures during the same febrile illness.
- Day nursery attendance.
- Family history of febrile seizure in a first degree relative.
What % of children will have another febrile convulsion?
1/3
When should urgent referral for assessment by a paediatrician be made for a febrile seizure?
1) First presentation of febrile convulsion
2) Diagnostic uncertainty
3) Aged <18 months; signs of CNS infection may be more subtle in these children
4) Antibiotics have recently been taken, due to potential masking of symptoms of meningitis
What is Todd’s paresis?
Transient hemiparesis following a seizure.
This is a potential short-term complication of complex or focal seizures in particular, and usually subsides completely within 48 hours.
