Syncope Flashcards
What is syncope
Syncope is the term used to describe the event of temporarily losing consciousness due to a disruption of blood flow to the brain, often leading to a fall
What are syncopal episodes also known as?
Syncopal episodes are also known as vasovagal episodes, or simply fainting.
What is a vasovagal episode caused by?
caused by a problem with the autonomic nervous system regulating blood flow to the brain.
Pathophysiology of vasovagal episode?
- When the vagus nerve receives a strong stimulus, such as an emotional event, painful sensation or change in temperature it can stimulate the parasympathetic nervous system.
- Parasympathetic activation counteracts the sympathetic nervous system, which keeps the smooth muscles in blood vessels constricted.
- As the blood vessels delivering blood to the brain relax, the blood pressure in the cerebral circulation drops, leading to hypoperfusion of brain tissue. This causes the patient to lose consciousness and “faint”.
S + S of syncope
Patients often remember the event and can recall how they felt prior to fainting. This is called the prodrome, and involves feeling:
- Hot or clammy
- Sweaty
- Heavy
- Dizzy or lightheaded
- Vision going blurry or dark
- Headache
What is essential to get an accurate impression of what happened?
Collateral history from someone that witnessed the event
What might a witness describe when they saw the person have a vasovagal episode?
- Suddenly losing consciousness and falling to the ground
- Unconscious on the ground for a few seconds to a minute as blood returns to their brain
- There may be some twitching, shaking or convulsion activity, which can be confused with a seizure
What happens if a patient maybe a bit groggy following a faint?
The patient may be a bit groggy following a faint, however this is different from the postictal period that follows a seizure. Postictal patients have a prolonged period of confusion, drowsiness, irritability and disorientation.
There may be incontinence with both seizures and syncopal episodes.
Primary syncope causes
- Dehydration
- Missed meals
- Extended standing in a warm environment, such as a school assembly
- A vasovagal response to a stimuli, such as sudden surprise, pain or the sight of blood
Secondary causes of syncope
- Hypoglycaemia
- Dehydration
- Anaemia
- Infection
- Anaphylaxis
- Arrhythmias
- Valvular heart disease
- Hypertrophic obstructive cardiomyopathy
- Panic/ anxiety
- Orthostatic syncope
- Drug-induced
- Neurological
- Cardiac and vascular syncope
History of syncope
Features that distinguish a syncopal episode from a seizure
After exercise? Syncope after exercise is more likely to be secondary to an underlying condition.
Triggers?
Concurrent illness? Do they have a fever or signs of infection?
Injury secondary to the faint? Do they have a head injury?
Associated cardiac symptoms, such as palpitations or chest pain?
Associated neurological symptoms?
Seizure activity?
Family history, particularly cardiac problems or sudden death?
Features of syncope
- 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
Features of seizure
- Epilepsy aura (smells, tastes or deja vu) before the event
- Head turning or abnormal limb positions
- Tonic clonic activity
- Tongue biting
- Cyanosis
- Lasts more than 5 minutes
- Prolonged post-ictal period
Examination of Syncope
- Are there any physical injuries as a result of the faint, for example a head injury?
- Is there a concurrent illness, for example an infection or gastroenteritis?
- Neurological examination
- Cardiac examination, specifically assessing pulses, heart rate, rhythm and murmurs
- Lying and standing blood pressure
Further examination of syncope
examination is often normal
pulse rate and rhythm
blood pressure - lying and standing
cardiac murmurs:
aortic stenosis
pulmonary stenosis
mitral stenosis
neurological examination - fundi, reflexes, any evidence of focal neurological signs
examination of tongue for bites, skin for bruising; both suggest seizures
Investigations of syncope
ECG, particularly assessing for arrhythmia and the QT interval for long QT syndrome
24 hour ECG if paroxysmal arrhythmias are suspected
Echocardiogram if structural heart disease is suspected
Bloods, including a full blood count (anaemia), electrolytes (arrhythmias and seizures) and blood glucose (diabetes)
Management of syncope
Fainting is common in children, particularly in teenage girls. They usually resolve by the time they reach adulthood. The most important aspect of management is making a confident diagnosis and excluding other pathology.
Seizures or underlying pathology need to be managed by an appropriate specialist.
Once a simple vasovagal episode is diagnosed, reassurance and simple advice can be given to:
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
DDs of syncope
Dizziness, vertigo and presyncope may be confused with syncope but these conditions do not cause loss of consciousness.
Biggest is epileptic seizure
Syncope Initial assessment of episode of transient loss of consciousness (NICE guidance)
Diagnose uncomplicated faint (uncomplicated vasovagal syncope) on the basis of the initial assessment when:
here are no features that suggest an alternative diagnosis (note that brief seizure activity can occur during uncomplicated faints and is not necessarily diagnostic of epilepsy) and
there are features suggestive of uncomplicated faint (the 3 ‘P’s) such as:
Posture - prolonged standing, or similar episodes that have been prevented by lying down
Provoking factors (such as pain or a medical procedure)
Prodromal symptoms (such as sweating or feeling warm/hot before TLoC)
if an uncomplicated faint is diagnosed then no further specialist assessment is indicated
If TLoC that is not uncomplicated faint, epilepsy, orthostatic hypotension or immediate (within 24 hours) referral for cardiovascular assessment then refer for cardiovascular assessment
Syncope as a result of orthostatic HT occurs only when …
patient is sitting or standing at the time of onset
In Syncope how long is the patient unconscious for?
patient is only unconscious for a short period of time unless the patient is sat up, resulting in more prolonged cerebral hypoxia
Syncope and convulsions
convulsions are uncommon in syncope unless the patient is sat up, in which case the seizure is a reflex response to cerebral hypoxia
Patient orientation and syncope
the patient rapidly becomes orientated once consciousness is regained, this is in contrast with the confusion following an epileptic seizure
After a careful history and examination and an ECG, how can we know something is vasovagal syncope?
occurs after pain or unpleasant site or smell
after prolonged standing
Orthostatic syncope
occurs when the patient stands up
Heart block syncope
past history of ischaemic or congenital heart disease
Situational syncope
events occur after micturition, defecation, coughing or swallowing
Drug-induced syncope
the patient is taking drugs which prolong the QT interval
Neurally mediated syncope
events associated with throat or facial pain
Syncope and cardiovascular disease
syncope with a family history of sudden cardiac death:
Long QT syndrome
Brugada syndrome
subclavian steal:
syncope is associated with work with the arms
frequent unexplained syncope with somatic symptoms:
psychiatric disease
Which patients should be investigated differently?
patients with no heart disease and normal ECG
patients with syncope and structural heart disease or with ECG abnormalities
Typical vasovagal syncope and driving
While standing
May drive and need not notify the DVLA
While sitting
May drive and need not notify the DVLA if there is an avoidable trigger which will not occur whilst driving.
Otherwise must not drive until annual risk of recurrence is assessed as below 20%
Syncope with avoidable trigger or otherwise reversible cause
Group 1
While standing
May drive and need not notify the DVLA
While sitting
Must not drive for 4 weeks. Driving may resume after 4 weeks only if the cause has been identified and treated. Must notify the DVLA if the cause has not been identified and treated.
Unexplained syncope, including syncope without reliable prodrome
and driving
This diagnosis may apply only after appropriate neurological and/or cardiological opinion and investigations have detected no abnormality.
Group 1
While standing or sitting
Must not drive and must notify the DVLA. If no cause has been identified, the licence will be refused or revoked for 6 months
Cardiovascular, excluding typical syncope driving
Group 1
While standing or sitting
Must not drive and must notify the DVLA.
Driving may be allowed to resume after 4 weeks if the cause has been identified and treated.
If no cause has been identified, the licence will be refused or revoked for 6 months
