CVS 12 (Shock) Flashcards Preview

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Flashcards in CVS 12 (Shock) Deck (42)
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1
Q

List some symptoms of Peripheral Artery Disease:

A
  • Intermittent claudication
  • Cold extremities
  • Weak pulse in legs/feet
2
Q

Which arteries are usually affected in Peripheral Artery Disease?

A
  • Femoral

- Iliac

3
Q

Define varicose veins:

A

Dilated torturous superficial veins

4
Q

Where is the most common location of venous ulcers, due to varicose veins?

A

Over the medial malleolus (great saphenous vein)

5
Q

Define shock:

A

Acute circulatory failure with either inadequate or inappropriately distributed tissue perfusion, resulting in generalised lack of oxygen supply to cells.
= Decreased MaBP due to decreased CO or TPR

6
Q

Name the 4 types of shock:

A

1) Distributive/Normovolaemic shock
2) Hypovolaemic shock
3) Cardiogenic shock
4) Mechanical shock

7
Q

Which types of shock are caused by a decreased cardiac output?

A
  • Hypovolaemic
  • Cardiogenic
  • Mechanocal
8
Q

Which type of shock are caused by a decreased total peripheral resistance?

A

Distributive

9
Q

Define cardiogenic shock:

A

Inability of heart to eject enough blood = decreased cardiac output

10
Q

Name some possible causes of cardiogenic shock:

A
  • Myocardial infarction
  • Arrhythmias
  • Acute heart failure
11
Q

What are the 2 types of mechanical shock, and name a common cause of each:

A

1) Due to restricted filling of heart
- Cardiac tamponade (infection/trauma/cancer/MI)

2) Due to obstruction to blood flow through lungs
- Pulmonary embolism (from DVT or surgery)

12
Q

Define hypovolaemic shock:

A

Decreased MaBP due to loss of circulating volume

13
Q

Name some possible causes of hypovolaemic shock:

A
  • Haemorrhage due to trauma
  • Severe burns
  • Severe diarrhoea/vomiting (massive loss of Na+)
14
Q

What percentage of blood must be lost for body to go into severe shock?

A

~ 30-40% of normal blood volume lost

15
Q

What type of receptors detect shock?

A

High pressure baroreceptors (in arteries)

Low pressure baroreceptors (in veins and heart)

16
Q

How do the high pressure baroreceptors respond when shock is detected?

A

Cause increase in SNS activity =

  • Tachycardia
  • Increased force of contraction (heart)
  • Peripheral vasoconstriction
  • Venoconstriction
17
Q

How do the low pressure baroreceptors respond when shock is detected?

A

Renal reflex (RAAS) activated:

  • Increased Angiotensin II = vasoconstriction
  • Increased aldosterone = increased H2O reabsorption
  • Increased ADH = increased H2O reabsorption
18
Q

Define ‘transcapillary refill’:

A

Movement of interstitial fluid into the vasculature (autoinfusion)

19
Q

What factor limits transcapillary refill during shock?

A

Haemodilution:

Movement of fluid from interstitium into the capillaries reduces the capillary oncotic pressure

20
Q

Decreased cerebral perfusion occurs at what MaBP?

A

< 60 mmHg

21
Q

What is the compensatory response during shock, when decreased cerebral perfusion is detected?

A

Massive increase in SNS innervation

22
Q

What are the classic symptoms of shock due to decreased CO?

A
  • Tachycardia
  • Weak pulse
  • Pale skin
  • Cold and clammy extremities
23
Q

Name the 2 types of distributive/normovolaemic shock:

A

1) Toxic/Septic

2) Anaphylactic

24
Q

List some risk factors for toxic/septic shock:

A
  • Diabetes
  • Immunocompromised
  • Catheter
  • Leukaemia/lymphoma
  • Long-term antibiotic use
  • Recent infection
  • Recent surgery
  • Recent steroid use
  • Transplant
25
Q

How does toxic/septic shock cause decrease in MaBP?

A

Endotoxins cause:

1) Vasodilation = decreased TPR
2) Increased vascular permeability = blood volume

26
Q

What are the classic symptoms of toxic/septic shock?

A
  • Tachycardia

- Warm and red extremities

27
Q

What are the symptoms of a pulmonary embolism?

A
  • Shortness of breath
  • Sharp, stabbing chest pain
  • Peripheral oedema
  • Cough
  • Cyanosis
28
Q

List some common causes of anaphylactic shock:

A
  • Medication ie Penicillin
  • Food ie Nuts/peanuts/wheat/shellfish
  • Insect stings
  • Latex
29
Q

What immune cell is responsible for an allergic reaction? What is the main mediator it releases?

A

Mast cell

Histamine

30
Q

Which mediators released in anaphylactic shock cause bronchoconstriction and laryngeal oedema?

A
  • PGD2

- Leukotrienes

31
Q

What are the classic symptoms of anaphylactic shock?

A
  • Tachycardia
  • Difficulty breathing
  • Red, warm extremities
  • Lightheaded/collapse/unconscious
  • Itchy skin/rash
32
Q

What is the treatment for anaphylactic shock?

A

Adrenaline shock ie EpiPen

33
Q

Define hypertension:

A

Sustained arterial BP > 140/90 mmHg

34
Q

What are some non-pharmacological treatments for hypertension?

A
  • Increase exercise levels
  • Weight loss
  • Decreased salt intake
35
Q

Name some commonly used drugs used to treat hypertension:

A
  • Diuretics (Usually Thiazide, if due to Conn’s syndrome use Aldosterone antagonists)
  • ACE inhibitors
  • DHP Ca2+ channel blockers
  • Alpha-1 antagonists
  • ARBs (Angiotensin II Receptor Blockers)
36
Q

What is the most common type of hypertension, and what is the cause?

A

Primary/essential hypertension

Unknown cause, associated with increased TPR

37
Q

How can renovascular disease cause secondary hypertension?

A

Can causes renal artery stenosis:

  • Decreased perfusion pressure activates RAAS
  • Vasoconstriction and Na+ retention at other kidney
38
Q

How can renal parenchymal disease cause secondary hypertension?

A

Damage to renal parechyma may reduce amount of vasodilators released:
- Decrease GFR = Na+ and H2O retention

39
Q

What is Conn’s syndrome?

A

Hypertension and hypokalaemia due to an Aldosterone-secreting adenoma

40
Q

How can Cushing’s syndrome cause secondary hypertension?

A

Excess cortisol acts on aldosterone receptors in late DCT and CD = H2O retention

41
Q

How can a Phaeochromocytoma cause secondary hypertension?

A

Tumour secretes catecholamines, which bind to alpha-1 adrenoceptors on vasculature = vasoconstriction

42
Q

What is the body’s major compensatory mechanism to shock?

A

Reabsorption of tissue fluids into plasma (transcapillary refill)