Diseases - Syncope + Shock |

Question 1

Syncope definition

Answer 1

Transient loss of consciousness due to cerebral hypoperfusion,
characterized by
rapid onset,
short duration,
and spontaneous complete recovery

Question 2

What is transient loss of consciousness

Answer 2

A state of real or apparent loss of consciousness with loss of awareness characterised by amnesia, loss of motor control, loss of responsiveness, and a short duration

Can result from
Trauma
Syncope
Epileptic seizure

Question 3

3 types of syncope

Answer 3

Reflex
Orthostatic
Cardiac

Question 4

Neural reflexes involved in reflex syncope

Answer 4

Cardioinhibition - Vagal stimulation decreases HR which decreases CO

Vasodepression - depression of sympathetic activity to blood vessels + vasodilation which decreases SVR, venous return and CO

Question 5

3 types of Reflex syncope

Answer 5

Vasovagal syncope
Situational syncope
Carotid sinus syncope

Question 6

Vasovagal syncope

Answer 6

Faint triggered by emotional distress or Orthostatic stress (standing for a long time)

Associated with
Pallor
Sweating
Nausea

Main risk is fall injury

Manage using - education, reassurance, avoidance of triggers and hydration

Question 7

Situational reflex syncope

Answer 7

Faint during or immediately after a specific trigger e.g. cough or swallowing

Management:
Treat cause if possible
Avoid dehydration and excessive alcohol
Cardiac permanent pacing may be required

Question 8

Carotid sinus reflex syncope

Answer 8

Triggered by mechanical manipulation of the neck
Common in elderly males
Associated with carotid artery atherosclerosis

Management:
Cardiac permanent pacing is generally recommended

Question 9

Orthostatic hypotension - definition + risk factors

Answer 9

Results from failure of baroreceptor responses to gravitational shifts in blood, when moving from horizontal to vertical position

Risk factors:
Elderly
Certain Medications
Certain diseases
Reduced intravascular volume
Prolonged bed rest

Question 10

Orthostatic hypotension - symptoms + test

Answer 10

Symptoms:
Light headedness, dizziness, blurred vision, faintness and falls

Positive result indicated by a drop within 3 minutes of standing from lying position
- In systolic BP of at least 20 mmHg with or without symptoms
- In diastolic BP of at least 10 mmHg with symptoms

Question 11

Cardiac syncope

Answer 11

Cardiac event causing sudden drop in Cardiac output
- arrhythmias
- acute MI
- structural cardiac disease - aortic stenosis, hypertrophic cardiomyopathy
- other cardiovascular disease - pulmonary embolism, aortic dissection

Question 12

Cardiac syncope suspected if

Answer 12

Syncope during excretion or when supine
Family history
Sudden onset palpitations followed by syncope

Question 13

What is shock

Answer 13

An abnormality of the circulatory system resulting in inadequate tissue perfusion and oxygenation - can lead to anaerobic metabolism, which will cause metabolic waste products to accumulate, resulting in cellular failure

Question 14

3 types of shock

Answer 14

Hypovalemic
Cardiogenic
Obstructive

Question 15

Hypovalemic shock

Answer 15

Shock due to decrease in blood volume leading to inadequate tissue perfusion
Either due to:
- Haemorrhage - direct blood loss
- Non-haemorrhage - decrease in ECFV

Question 16

Compensatory mechanisms in Hypovalemic shock

Answer 16

• body can maintain BP until >30% of blood is lost
• In haemorrhagic shock baroreceptor reflex causes patient to become tachycardic
• SVR increases through vasoconstriction - cool peripheries
  Myogenic response - intrinsic ability of smooth muscle to alter SVR

Question 17

Cardiogenic shock

Answer 17

Decreased cardiac contractility (e.g. due to acute MI)
→ decreased stroke volume → decreased CO and BP
→ inadequate tissue perfusion

Question 18

Obstructive shock

Answer 18

Shock associated with physical obstruction of the great vessels or heart itself
- cardiac tamponade - fluid sac around heart fills with blood putting pressure on the heart
- pulmonary embolism
- tension pneumothorax - increased intrathoracic pressure -> decreased venous return

Question 19

Distributive shock - 2 types

Answer 19

Neurogenic - spinal cord injury
Vasoactive shock - septic shock, anaphylactic shock

Question 20

Neurogenic distributive shock

Answer 20

Loss of sympathetic tone to blood vessels and heart causing massive venous and arterial dilation and heart rate slows

Question 21

Vasoactive distributive shock

Answer 21

Release of massive vasoactive mediators causing massive venous and arterial vasodilation
Increased capillary permeability causing decreased venous return

Question 22

General Management of shock

Answer 22

ABCDE approach
High flow oxygen

Question 23

Management for Hypovalemic shock

Answer 23

Volume replacement

Question 24

Management for cardiogenic shock

Answer 24

Inotropes

Question 25

Management for tension pneumothorax

Answer 25

Immediate chest drain

Question 26

Management for anaphylactic shock

Answer 26

Adrenaline

Question 27

Management for septic shock

Answer 27

Vasosupressors