Physiology of shock and treatment

Question 1

What is shock?

Answer 1

Condition of inadequate perfusion to sustain normal function.

Question 2

Main different types of shock?

Answer 2

Hypovolaemic
Cardiogenic
Distributive
Obstructive

Question 3

What are the different sub-types of distributive shock.

Answer 3

Anaphylactic
Neurogenic
Septic
Cytotoxic

Question 4

Hypovolaemic shock example causes?

Answer 4

Loss of blood or other bodily fluids such as third space losses or bleeding. Another cause includes severe dehydration.

Question 5

How many classes of hypovolaemia are there?

Answer 5

4 classes. Classes 1-4.

Question 6

To compensate for hypovolaemic shock how does baroreceptor reflex contribute?

Answer 6

Stretch sensitive receptors in the carotid sinus (glossopharyngeal nerve aka CN 9) and aortic arch (vagus nerve aka CN 10).

If blood pressure falls due to hypovolaemic shock. The baroreceptor reflexes act to restore blood pressure by increasing heart rate.

Question 7

What is the carotid sinus?

Answer 7

A baroreceptor sensing change in systemic blood pressure. Sensory innervation supplied by a branch of the glossopharyngeal nerve (cranial nerve 9).

Question 8

What is the aortic arch?

Answer 8

Another baroreceptor sensing change in blood pressure. Sensory innervation is supplied by the vagus nerve (cranial nerve 10).

Question 9

What is cardiac output?

Answer 9

Amount of blood pumped by the heart per minute.

Question 10

Treatment of hypovolaemic shock?

Answer 10

Fluid replacement. Electrolytes may also be added depending on patient needs.

Question 11

What is cause of cardiogenic shock? Examples?

Answer 11

Myocardial dysfunction causing reduction in systolic function and cardiac output. Causes include myocardial infarction, myocarditis and acute valve lesion.

Question 12

Cardiogenic shock clinical signs?

Answer 12

Poor forward flow - hypotension/shock, fatigue and syncope.
Backpressure - pulmonary oedema. elevated JVP

Question 13

Cardiogenic shock can be treated with medication. True/false?

Answer 13

True. Treatment can be done with beta and dopaminergic stimulation. Intra-aortic balloon pumps can be used if pharmacological treatment prove ineffective.

Question 14

What is obstructive shock? List some causes.

Answer 14

Physical obstruction to filling of the heart leading to reduced preload and cardiac output.

Causes with treatment:
Pulmonary embolism - anticoagulation +/- thrombolysis.
Cardiac tamponade - pericardial drainage
Tension pneumothorax - decompression and chest drainage.

Question 15

What is risen during septic shock (and can indicate presence of septic shock)?

Answer 15

Lactate levels

Question 16

Management of septic shock?

Answer 16

Early antibiotic treatment

Question 17

Underlying science of anaphylactic shock? What chemical is released?

Answer 17

Uncontrolled activation and degranulation of mast cells. Release of histamine with resulting uncontrolled vasodilation.

Question 18

Management of anaphylactic shock?

Answer 18

Adrenaline acts as both a vasoconstrictor and a mast cell stabiliser.

Question 19

How does neurogenic shock most occur?

Answer 19

Follows spinal cord of central trauma.

Question 20

Management of neurogenic shock?

Answer 20

Dopamine alongside vasopressors is the main treatment option.