Syncope

Question 1

Define syncope

Answer 1

A transient, self limited LOC
Onset rapid
Recovery is spontaneous, complete and usually prompt
Transient global cerebral hypoperfusion

Question 2

How does cerebral autoregulation relate to syncope?

Answer 2

Cerebral blood flow can be maintained over a wide range of systolic blood pressures.
Arterioles are pressure sensitive so can dilate/constrict with changes in blood pressure in order to maintain constant flow
However deviates rapid once outside of this range

Question 3

What are the two main classifications of disorders that cause a real or apparent loss of consciousness?

Answer 3

Syncope
Non-syncopal

Question 4

What are the different types of syncope?

Answer 4

Neurally mediated reflex syncopal syndromes
Orthostatic
Cardiac arrhythmias
Structural cardiac/cardiopulmonary disease
Cerebrovascular - steal syndromes

Question 5

What are some examples of non-syncopal conditions? of real or apparent loss of consciousness

Answer 5

Disorders resembling syncope with impairment or loss of consciousness e.g seizures

Disorders resembling syncope without impairment of loss of consciousness (e.g psychogenic syncope)

Question 6

What is the relevant epidemiology of syncope?

Answer 6

Prevalence of 10% of adults
Lifetime risk up to 70yrs of 42%

Makes up 3-5% of ED atttendances
1-3% of hospital admissions

Question 7

How does age relate to syncope risk?

Answer 7

Vasovagal syncope starts to appear in adolescence and is then common
Syncope is most common in the elderly -> rising greatly from 70yrs due to inc co-morbidities and changes in cerebrovascular system.
Peak age in 70yrs+

Question 8

In what cases of syncope can have increased mortality rates?

Answer 8

Patients that have:
Left ventricular failure
Hypertrophic cardiomyopathy
Aortic stenosis
Previous ventricular arrhythmia

Question 9

In what cases does syncope have no effect on mortality?

Answer 9

Young patients without heart disease and normal ECGs
Neurally mediated syndromes

Question 10

What is a reflex-mediated syncope?
What are some examples?

Answer 10

Also called a neurologically mediated syncope
When a brain reflex causes a transient decrease in blood pressure and loss of consciousness.
Vasovagal syncope
Carotid sinus syndrome
Situational syncope

Question 11

What are some example situations that can cause situation syncope?

Answer 11

Cough
Micturition
Deaecation
Brass instrument players
Adolescent stretch

Question 12

What is meant by orthostatic hypotension?
What are the two most common causes?

Answer 12

Fall of SBP>20mmHg or DBP>10mmHg within three minutes of standing compared to lying down - due to lack of vasoconstriction.
Drugs - for example alpha-1 receptor blockers
Autonomic failure

Question 13

What are cardiac causes of syncope?

Answer 13

Arrhythmia - Complete heart block, ventricular tachycardia
Structural cardiac disease - aortic stenosis, cardiomyopathy.

Question 14

What clinical questions are important to answer when assessing a patient with a potential syncope?

Answer 14

If loss of consciousness if attributable to syncope or not
Is heart disease present or absent?
Are there important clinical features in the history that suggest the diagnosis?

Question 15

What pre-disposing factors are important to ask about in a syncope history?

Answer 15

Position - supine, sitting, standing
Activity - rest, change in posture, during (cardiac) or after exercise, urination, defaecation, cough, swallowing.
Pre-disposing - crowded or warm, prolonged standing, post-prandial.
Precipitating - fear, intense pain, neck movements.

Question 16

What prodromal symptoms are common in vasovagal syncope?

Answer 16

Lightheadedness
Dizziness
Nausea
Diaphoresis (excessive sweating)
Visual disturbances (tunnel vision or blurred)
Tinnitus or muffled hearing
Pallor

Question 17

What questions might you want to ask an eye-witness of a ?syncope episode?

Answer 17

Skin colour - pallor, cyanosis
Duration of loss of consciousness
Movements and their duration
Tongue biting (side or tongue or back is more likely in epilepsy)

Question 18

What symptoms is it important to ask about at the end of ?syncopal episode?

Answer 18

Sweating, feeling of cold, nausea
Confusion, focal neurology
Skin colour
Injury
Chest pain, palpitations

Question 19

What background health questions are important in a patient with a ?syncope?

Answer 19

Family history of sudden death, congential arrhythmogenic heart disease or fainting
Previous cardiac disease
Neurological history
Metabolic disorders
Medication (Hypotensive, antiarrhythmic, QT prolongating agents)

Question 20

What examss/investigations should be done on a patient with ?syncope episode?

Answer 20

Signs of cardiac failure/murmurs - echo and heart sounds
Neurological evaluation
12 Leag ECG
Tilt table testing - (can confirm vasovagal)
Carotid sinus massage - in absence of bruits/disease

Question 21

What are the three main classifications of syncopal disorders?

Answer 21

Reflex (neurally mediated) - situational, vasovagal etc
Cardiac syncope - structural or arrhythmia cause low CO
Orthostatic hypotension - can be primary or secondary

Question 22

How can you differentiate between syncope and seizures?

Answer 22

Present similarly
Seizure tend to have more post-ictal confusion for 10-15 minutes or other neurological symptoms such as tongue bitting or incontinence

Question 23

How to differentiate between syncope and stroke?

Answer 23

Syncope makes stroke a less likely diagnosis
TIA’s can cause transient loss of consciousness but are typically associated with other focal neurological signs.

Question 24

What is the initial management of syncope?

Answer 24

Stabilisation
Assess and treat any potentially life-threatening conditions. (patient safety, airway, breathing and circulation)
Patient should sit or stand - may elevated legs to improve cerebral blood flow and monitor vital signs
Identify and fix any reversible causes such as hypoglycaemia.

Question 25

What vagal manoeuvres can be used to prevent vasovagal syncope?

Answer 25

Sitting and crossing legs
Coughing
Valsalva (holding deep breath and strain as if constipated)

Question 26

How common is a vasovagal syncope?

Answer 26

Is a reflex syncope
Accounts for up to 50% of syncope

Question 27

What causes a vasovagal syncope?

Answer 27

Most commonly triggered by emotions such as fear, pain or the sight of blood.
Results in decreased ventricular filling pressures triggering the cycle.

Question 28

What is the loss of consciousness like in vasovagal syncope?

Answer 28

Sudden and brief - accompanied by a loss of postural tone
Lasting several seconds to one minute

Question 29

What are the features of recovery after a vasovagal syncope?

Answer 29

Confusion or disorientation lasting for several seconds to minutes
Fatigue or weakness
Recollection of prodromal symptoms but amnesia for the actual syncopal event

Question 30

What simple measures can be used to manage a reflex syncope?

Answer 30

Patient education (prodromal and counter pressure manoeuvres) and reassurance (benign)
Lifestyle - avoid dehydration, prolonged standing, exposure to hot environments, rise slowly, adequate salt intake

Question 31

What is the mechanism underpinning vasovagal syncope?

Answer 31

Over activation of the sympathetic nervous system by fear or excitement
Activates the parasympathetic as a biological safety mechanism, this hijacks the brain
Leads to rapid drop in blood pressure and HR
Leads to reduced blood flow to the brain and reduced intracranial pressure
Temporary ischemic conditions cause loss of postural tone
Baroreceptors are temporaly inhibited by the parsympathetic nervous system.