P9- Shock and atheroma (atherosclerosis) Flashcards Preview

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Flashcards in P9- Shock and atheroma (atherosclerosis) Deck (59)
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1

what do all causes of shock result in?

acute circulatory failure with hypotension and inadequate tissue perfusion

2

what is a large component of the syndrome, regardless of aetiology?

failure of microcirculation

3

what happens if shock is not reversed quickly?

leads to multiorgan failure and death

4

Name the 5 major types of shock.

-Hypovolaemic
-septic
-cardiogenic
-anaphylactic
-neurogenic

5

What are other causes of shock?

Include ‘Chemical’ shock eg
acute pancreatitis, acute peritonitis from perforated gastric ulcer

6

What is hypovolaemic shock due to?

- Due to reduced blood volume
eg haemorrhage,vomiting, diarrhoea,
burns
- Inadequate circulating volume

7

what is susceptibility to hypovolaemic influenced by?

age and prior health if patients

8

Who tolerate blood loss less well?

elderly and hypertensive patients

9

How much blood can be lost that is still asymptomatic?

10% in healthy adult

10

what does rapid loss of half blood volume lead to?

coma and death

11

What causes septic shock?

- Severe infection, often Gram-negative bacilli that produce endotoxins
- LPS, liopolysaccahride, from the outer cell wall of the bacilli binds to and activates macrophages and endothelial cells
- TNF-α---IL-1- cytokine cascade

12

What does septic shock lead to?

Peripheral vasodilation, tissues underperfused, endothelial injury, fluid leakage, oedema, activated coagulation, DIC (disseminated intravascular coagulation)

13

Describe cariogenic shock.

- Severe acute reduction in cardiac output due to pump failure
- Massive myocardial infarct, arrhythmia, cardiac tamponade, pulmonary embolism, valve dysfunction
- Failure to maintain perfusion pressure and flow

14

what type of reaction is anaphylactic shock?

Systemic Type I Hypersensitivity

15

What happens in anaphylactic shock?

Massive mast cell degranulation causes release of vasodilators and permeability factors

16

Name 2 types of neurogenic shock.

• Acute brain injury
• Spinal cord injury

17

What role do compensatory mechanisms play?

In the early stages, compensatory mechanisms maintain blood flow to vital organs- CNS, heart, Kidneys- reduced perfusion to other tissues

18

Give examples of compensatory mechanisms.

- Increased sympathetic activity
-Renin-Angiotensin-Aldosterone system
- CNS, heart and kidney autoregulate their own perfusion

19

What happens if tissue perfusion is not restored urgently after shock?

ischaemia causes multiorgan failure and death

20

what is the shock consequence to the lungs?

Diffuse alveolar injury (ARDS Adult Respiratory Distress Syndrome)

21

what is the shock consequence to the heart?

ischaemia and failure

22

what is the shock consequence to the gut?

ischaemia and endotoxaemia

23

what is the shock consequence to the adrenal?

initially stimulated then failing

24

what is the shock consequence to the brain and kidneys?

-initially auto regulated blood supply
-later loss of consciousness and acute renal failure

25

How do shocked patients present?

-Restless
-Confused
-Pale
-Cold
-Sweaty skin
-Rapid weak pulse
-Low BP
-Increased rate and depth of respiration
-Eventually drowsy then comatose

26

Give the layers of a normal artery from the inside out.

-endothelium
-intima
-elastic lamina
-media
-adventitia

27

what are artery structural adapted to?

pressure and flow of blood within them

28

What does the aorta do?

multiple layers of elastic tissue to absorb impulse of cardiac systole and maintain blood flow in diastole

29

what do the medium-sized arteries do?

Medium-sized arteries regulate distribution of blood to various organs by constriction and dilatation, so possess thick medial wall with less elastic tissue

30

what is the most important disease of arteries?

Atheroma (Atherosclerosis)