Syncopy

Question 1

Define a transient loss of consciousness

Answer 1

A state of real or apparent loss of consciousness with loss of awareness

Characterised by:

• amnesia (for duration of unconsciousness)
• loss of motor control
• loss of responsiveness
• short duration

Question 2

List some of the characterising features of a transient loss of consciousness

Answer 2

• amnesia (for duration of unconsciousness)
• loss of motor control
• loss of responsiveness
• short duration

Question 3

Is syncope the only cause of a transient loss of consciousness?

Answer 3

No

other things like head trauma, epilepsy etc. can cause it

Question 4

Define syncope

Answer 4

Transient loss of consciousness due to cerebral hypoperfusion

Question 5

List the characteristics of syncopy

Answer 5

• rapid onset
• short duration
• spontaneous full recovery

Question 6

Define cerebral hypoperfusion

Answer 6

Reduced blood perfusion of the brain

Question 7

List the types of syncope

Answer 7

• Reflex syncope (vasovagal, situational, carotid sinus)
• Orthostatic hypotension
• Cardiac syncope

Question 8

Define reflex syncope

Answer 8

Syncope where neural reflexes modify heart rate and/or vascular tone

Question 9

Describe the basic process that causes reflex syncope

Answer 9

Neural reflexes decrease heart rate and/or vascular tone
-->
Predisposing to a fall in MAP
-->
MAP fall causes cerebral hypotension
-->
Transient cerebral perfusion decreased 
-->
Syncope (or near syncope)

Question 10

What is the most common type of syncope?

Answer 10

Vasovagal syncope

Question 11

Describe how neural reflexes decrease heart rate and/or vascular tone in reflex syncope

And the effect this has on MAP

Answer 11

Heart rate decrease:

• Vagal stimulation
• Decreased heart rate
• Cardiac output decreased
• MAP decreased

Vascular tone decrease:

• Decrease in vasomotor tone
• SVR decrease, venous return decrease, SV decrease
• Cardiac output and thus MAP decreases

Question 12

Define vascular tone

Answer 12

The degree of constriction of a blood vessel

Decreased tone = vasodilation
Increased tone = vasoconstriction

Question 13

List the types of reflex syncope

Answer 13

• Vasovagal
• Situational
• Carotid sinus

Question 14

Describe vasovagal reflex syncope

Describe its prodrome

Aversion?

Answer 14

• Due to emotional distress (or orthostatic stress)
• Typical prodrome (sweating, pallor, nausea)
• Can be averted during prodrome (lie down - increase venous return)
• Most common type of syncope

Question 15

What is the main risk of vasovagal reflex syncope?

Answer 15

Injury due to falling over

Question 16

What is the treatment for vasovagal reflex syncope?

Answer 16

• Education on triggers
• Avoidance of triggers
• Adequate hydration

Question 17

Is vasovagal reflex syncope linked to increased mortality?

Answer 17

No

Question 18

Describe situational reflex syncope

Answer 18

• Syncope during/immediately after a specific stimulus
  e. g. cough, swallowing, micturition
• Less common

Question 19

Describe the treatment for situational reflex syncope

Answer 19

• Treat the stimulus (e.g. cough)
• Advise patient lies down during stimulus (e.g. coughing)
• Avoid dehydration and excessive alcohol
• Cardiac pacemaker (if bad)

Question 20

Describe carotid sinus reflex syncope

Answer 20

Syncope triggered by mechanical manipulation of the neck

• more common in elderly, and males
• associated with atherosclerosis

Question 21

Describe the treatment for carotid sinus reflex syncope

Answer 21

• Cardiac pacemaker

Question 22

What events can predispose to carotid sinus reflex syncope

Answer 22

• head and neck surgery

- radiation of the head and neck

Question 23

Define postural (orthostatic) hypotension

Answer 23

Hypotension due to the failure of the baroreceptor reflex to respond to gravitational shifts in blood (usually when standing up)

Question 24

List the risk factors of postural (orthostatic) hypotension

Answer 24

• Age related
• Medications
• Certain diseases
• Reduced intravascular volume
• Prolonged bed rest

Question 25

What are the signs and symptoms of postural (orthostatic) hypotension?

Answer 25

- syncope - lightheadedness - dizziness - blurred vision - faintness - falls

Question 26

What is the clinical test for postural (orthostatic) hypotension?

Answer 26

Within 3 mins of standing from lying down, either: - Systolic Bp drop of 20 mmHg or - Diastolic Bp drop of 10 mmHg (with symptoms)

Question 27

Describe cardiac syncope

Answer 27

Syncope due to a cardiac event that causes a sudden drop in cardiac output

Question 28

List possible causes of cardiac syncope

Answer 28

- Arrhythmias: resulting in bradycardia or tachycardia - Acute Myocardial infarction - Structural Cardiac Disease: e.g. aortic stenosis, hypertrophic cardiomyopathy - Other Cardiovascular Disease: e.g. pulmonary embolism, aortic dissection

Question 29

How does an arrhythmia that causes tachycardia result in the decreased cardiac output seen in cardiac syncope?

Answer 29

``` The increased HR doesn't allow for complete filling of the ventricles --> Stroke volume decreased --> Cardiac output decreases ```

Question 30

Describe findings that suggest cardiac syncope

Answer 30

- Syncope during excretion or when supine - Presence of a structural cardiac abnormality or coronary heart disease - A family history of sudden death at young age - Sudden onset palpitations immediately followed by syncope - Findings on ECG suggestive of arrhythmic syncope

Question 31

Describe how to initially evaluate a patient presenting with transient loss of consciousness

Answer 31

- Careful history - Any witnesses - Fully physical examination - Orthostatic blood pressure measurement - 12-lead ECG