SYNCOPE

Question 1

What is syncope?

Answer 1

A transient, spontaneous loss of consciousness followed by complete recovery

Question 2

What causes syncope?

Answer 2

Neurally-mediated reflex syncope
Orthostatic syncope
Cardiac syncope
Epileptic seizures

Question 3

What causes syncope?

Answer 3

Global cerebral hypoperfusion due to an abrupt fall in blood pressure

Question 4

What is neurally-mediated reflex syncope?

Answer 4

vasovagal: triggered by emotion, pain or stress. Often referred to as ‘fainting’
situational: faint with an identifiable trigger (cough, micturition, gastrointestinal)
carotid sinus syncope

Question 5

What is vasovagal syncope? What is the pathophysiology?

Answer 5

Triggered by emotion, pain or stress

Triggering event ->
Cardioinhibitory response: increased parasympathetic activity that causes altered electrical activity in the heart manifesting as bradycardia (or higher degree of heart block).
Vasodepressor response: decreased sympathetic activity that leads to systemic vasodilatation and subsequent hypotension.
Cerebral hypoperfusion = temporary loss of conciousness

Question 6

What’s the most common type of syncope?

Answer 6

Vasovagal syncope (over 1/3rd of cases)

Question 7

What are classic triggers for vasovagal syncope?

Answer 7

Emotional events
Painful or noxious stimuli
Prolonged standing
Heat exposure
Physical exertion

Some patients may have no specific trigger, particularly in the elderly.
If there is a very specific trigger e.g. micturition its known as situational syncope

Question 8

What are clinical features of vasovagal syncope?

Answer 8

Typically occurs when standing or sitting
Prodromal phase - lightheadidness, pallor, sweating, temp changes, palpitations, nausea, visual alteration, reduction in hearing
Brief loss of conciousness (8-12 seconds)
Post-syncope fatigue

Question 9

How is vasovagal syncope diagnosed?

Answer 9

thorough history and clinical examination
Witness
During the event hypotension and bradycardia are commonly observed but physical exam is otherwise normal
Capillary BG
ECG monitoring
VBG
Bloods - FBC, U&E
Tilt-table test if recurrent (to see if syncope is accompanied by a severe cardioinhibitory response)

Question 10

What is the tilt-table test?

Answer 10

The test first involves putting the patient on a motorised table with ECG monitoring. Continuous assessments are then made including beat-to-beat blood pressure, heart rate, symptoms, and ECG changes as the patient is moved from a supine position to a head-up position at 60-80º. The idea is to induce syncope and assess the changes on non-invasive monitoring. Provocation drugs may be used if syncope does not occur during passive monitoring.

A positive test for vasovagal syncope is suggested by the development of syncope during the test with evidence of a cardioinhibitory and/or vasodepressor response that leads to hypotension.

Question 11

How do you manage vasovagal syncope?

Answer 11

Only required in recurrent cases

Conservative - trigger avoidance, pt education, increase fluid intake, increase salt intake, compression stockings, DVLA consideration
Medical therapy - fludrocortisone, midodrine
Other - older pt with significant cardioinhibitory response may be considered for permenant pacing

Question 12

why should you increase salt intake for vasovagal syncope?

Answer 12

NaCl - increasing Na+ can increase blood volume
(Bare in mind you shouldn’t do this for pt with hypertension or hart disease)

Question 13

How does fludrocortisone help manage vasovagal syncope?

Answer 13

It’s a potent mineralocorticoid that enhances fluid retention by acting on kidneys to increase Na+ and water retention
Increasing blood volume and blood pressure can reduce the risk of syncope

Question 14

How does midodrine help manage vasovagal syncope?

Answer 14

Midodrine is an alpha-adrenergic receptor agonist that increases vascular tone
Limited evidence and side effects often lead to cessation e.g. supine hypertension and frequent urination

Question 15

What is carotid sinus syndrome?

Answer 15

A type of neurally-mediated reflex syncope
Hypersensitivity of carotid sinus baroreceptor causes bradycardia and/or vasodilation

This can occur when pressure is applied to the neck, such as when wearing a tight collar or shaving, or as a result of a carotid sinus massage or other medical procedure.

Question 16

What is situational syncope?

Answer 16

A type of neurally-mediated reflex syncope?
Fainting with an identifiable trigger

Question 17

What are the 3 types of neurally-mediated reflex syncope?

Answer 17

Vasovagal syncope
Carotid sinus syndrome
Situational syncope

Question 18

What is orthostatic hypotension?

Answer 18

a fall in systolic blood pressure of at least 20 mmHg (at least 30 mmHg in people with hypertension) and/or a fall in diastolic blood pressure of at least 10 mmHg within 3 minutes of standing.

Question 19

What causes orthostatic hypotension?

Answer 19

Primary autonomic failure - parkinsons, Lewy body dementia
Secondary autonomic failure - diabetic neuropathy, amyloidosos, uraemia
Drug-induced
Volume depletion e.g. haemorrhage, diarrhoea, dehydration
Prolonged bed rest causing physical deconditioning

Question 20

What drugs can cause orthostatic hypotension?

Answer 20

diuretics - can lead to dehydration
alcohol
vasodilators
Anti-hypertensives
Alpha-adrenoreceptor blockers

Question 21

What can cause cardiac syncope?

Answer 21

Arrhythmias
Structural heart disease - Valvular heart disease, cardiomyopathy, congenital heart defects
Obstruction of blood flow - aortic stenosis, PE, hypertrophic cardiomyopathy, MI
Brugada syndrome
Long QT syndrome

Question 22

Whats the most common cause of syncope in all age groups?

Answer 22

Reflex syncope
(Orthostatic and cardiac causes become progressively more common in older patients)

Question 23

Outline the epidemiology of syncope?

Answer 23

1 in 2 people will experience syncope at some point in their life
1% of A&E visits are due to syncope

Question 24

What are complications of syncope?

Answer 24

Injuries associated with sudden loss of conciousness

Question 25

Whats the prognosis of syncope?

Answer 25

Vasovagal syncope and situational syncope are generally associated with a good overall prognosis.
Orthostatic hypotension is generally associated with a good prognosis although the person’s long-term prognosis may be affected by some of the possible underlying causes for the condition (such as diabetes and Parkinson’s disease).
An underlying cardiac cause for blackout is associated with a poorer prognosis

Question 26

When should you suspect an underlying cardiac cause for syncope?

Answer 26

ECG abnormalities
Suspected/confirmed HF
Blackout occurring during exertion
Palpitations before loss of conciousness
FHx of sudden cardiac death in people younger than 40
New or unexplained breathlessness
Heart murmur
Blackout without prodromal symptoms in people >65 years.

Question 27

When should you suspect epilepsy as an underlying cause for syncope?

Answer 27

Prodromal déjà vu, or jamais vu
A bitten tongue
Head-turning to one side during the blackout
Loss of bowel and bladder control
Unusual posturing
Prolonged limb-jerking
Confusion following the event

Question 28

When should you suspect an uncomplicated vasovagal syncope?

Answer 28

An absence of features to suggest an alternative diagnosis (note: brief seizure activity can occur during uncomplicated faints and is not necessarily diagnostic of epilepsy) and
The presence of features suggestive of uncomplicated faint (the 3 ‘P’s):
Posture — blackout occurred after prolonged standing. Similar episodes may 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 the blackout occurred.

Question 29

When should you suspect situational syncope?

Answer 29

There are no features to suggest an alternative diagnosis and
Syncope is clearly and consistently provoked by straining during micturition (usually while standing), defecation, or by coughing or swallowing.

Question 30

When should you suspect carotid sinus syndrome?

Answer 30

if the blackouts occurred while turning the head to one side, particularly in men aged 50 years or older.

Question 31

When should you suspect orthostatic hypotension?

Answer 31

An absence of features suggesting an alternative diagnosis and
A typical history — light-headedness, dizziness, weakness, tunnel vision. Symptoms should not occur while supine, should get worse on standing, and should be relieved by sitting or lying down. Some people may present with recurrent or unexplained falls. Symptoms are often worse early in the morning, in hot environments, after meals, after standing motionless, and after exercise.
May also have underlying causes e.g. meds, prolonged bed rest, parkinsons etc

Question 32

How should you investigate suncrope?

Answer 32

Capillary blood glucose, VBG, FBC, U&Es
cardiovascular examination
postural blood pressure readings
carotid sinus massage
tilt table test
24 hour ECG

Question 33

How should you manage a pt with syncope?

Answer 33

Advise pt not to drive until specialist assessment
Refer to cardiac if suspecting cardiovascular cause or orthostatic hypotension and neurology if suspecting epilepsy

Question 34

How should you manage orthostatic hypotension?

Answer 34

Consider likely causes, review drug therapy
Explain mechanisms causing blackouts

Lifestyle -
when going from supine to standing advise to sit first
Increase salt intake unless contraindicated
Drink strong tea or coffee
Drink >2L water a day
Avoid alcohol
Tilt head up during sleeping

Treat constipation aggressively as vasalva manouvre can worsen syncope