Pathophysiology of Congestion & Oedema Flashcards Preview

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Flashcards in Pathophysiology of Congestion & Oedema Deck (61)
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1
Q

What does water flow down?

A

Concentration/pressure gradient

2
Q

What is Darcy’s law?

A

Q is blood flow

P is pressure

R is resistance

3
Q

What is congestion?

A

Relative excess of blood in vessels of tissue or organ

4
Q

What are clinical pathological examples of congestion?

A

Local acute congestion (deep vein thrombosis)

Local chronic congestion (hepatic cirrhosis)

Generalised acute congestion (congestive cardiac failure)

5
Q

What is deep vein thrombosis?

A

Thrombus forms in one or more of the deep veins in your body, usually in your legs

6
Q

What is it called when a thrombus forms in one or more of the deep veins in your body, usually in your legs?

A

Deep vein thrombosis

7
Q

What is the pathophysiological process of deep vein thrombosis?

A

1) Blood backs up in veins, venules and capillaries
2) Decreased outflow of blod
3) Local, acute congestion
4) Decreased pressure gradient
5) Decreased flow across system
6) No oxygen leading to ischaemia and infarction

8
Q

What is hepatic cirrhosis?

A

Liver does not unfction properly due to long term damage

9
Q

What is it called when the liver does not function properly due to long term damage?

A

Hepatic cirrhosis

10
Q

What could hepatic cirrhosis be due to?

A

HBV or alcohol

11
Q

What does hepatic cirrhosis lead to?

A

Loss of normal architecture leading to altered hepatic blood flow

Portal blood flow blocked

Haemorrhage risk

12
Q

What is congestive cardiac failure?

A

Heart muscle does not pump blood as well as it should

13
Q

What is it called when the heart muscle does not pump blood as well as it should?

A

Congestive cardial failure (or heart failure)

14
Q

What is congestive cardiac failure also known as?

A

Heart failure

15
Q

What could congestive cardiac failure be due to?

A

Ischaemia

Valvular disease

16
Q

What is the pathophysiology of congestive cardiac failure?

A

Decreased cardiac output

Decreased renal glomerular filtration rate

Increased amount of fluid in the body

Fluid overload in the veins

17
Q

What does decreased renal glomerular filtration rate during congestive cardiac failure lead to?

A

Activation of renin-angiotensin-aldosteron system

Increased sodium and water retention

18
Q

What are some of the effects of congestive cardiac failure?

A

Heart cannot clear blood from ventricles

Back pressure, blood dammed back in veins

Pulmonary oedema in lefts (leading to left heart failure where blood dams back into lungs)

Central venous congestion in liver (leading to right heart failure where blood backs into systemic circulation)

19
Q

What does central venous congestion in liver during congestive cardiac failure cause?

A

Right heart failure

Increased jugular venous pressure

Hepatomegaly

Peripheral oedema

20
Q

What is hepatic central venous congestion?

A

Liver dysfunction due to venous congestion usually due to congestive heart failure

21
Q

What is liver dysfunction due to venous congestion usually due to congestive heart failure called?

A

Hepatic central venous congestion

22
Q

How are pericentral and periportal hepatocytes different in hepatic central venous congestion?

A

Pericentral hepatocytes are red due to poorly oxygenated blood

Periportal hepatocytes are pale due to better oxygenated blood because of proximity of hepatic arterioles

23
Q

What is the normal microcirculation?

A

Constant movement of fluid through capillary beds

24
Q

What is normal microcirculation driven by?

A

Hydrostatic pressure from the heart

25
Q

What is the hydrostatic pressure from the heart balanced by?

A

Osmotic pressures and endothelial permeability

26
Q

How does the hydrostatic and oncotic pressure compare in arterial side and venous side?

A

In arterial side hydrostatic is greater than oncotic so fluid moves out of vessel into interstitial space

In venous side oncotic is greater than hydrostatic so fluid moves into vessel from interstitial space

27
Q

What are 3 components that affect net flux and filtration?

A

Hydrostatic pressure

Oncotic pressure

Permeability characteristics and area of endothelium

28
Q

What does disturbances to the normal components that affect net flux and filtration cause?

A

Oedema

29
Q

What is oedema?

A

A condition characterised by an excess of watery fluid collecting in the cavities or tissues of the body

30
Q

What is a condition characterised by an excess of watery fluid collecting in the cavities or tissues of the body?

A

Oedema

31
Q

What is effusion?

A

Accumulation of fluid in body cavities

32
Q

What is accumulation of fluid in body cavities called?

A

Effusion

33
Q

What are examples of different kinds of effusions?

A

Pleural

Pericardial

Joint effusions

Abdominal cavity (ascites)

34
Q

What are the 2 kinds of oedema?

A

Transduate

Exudate

35
Q

What are transduate oedema due to?

A

Alterations in the haemodynamic forces which act across the capillary wall

(cardiac failure)

(fluid overload)

36
Q

What is present and not present in transduate?

A

Not much protein/albumin

Lots of water and electrolytes

37
Q

What is the specific gravity of transudate?

A

Low specific gravity

38
Q

What is exudate due to?

A

Inflammatory process due to increased vascular permeability

(tumour)

(inflammation)

(allergy)

39
Q

What is present and not present in exudate?

A

Higher protein/albumin content

Lots of water and electrolytes

40
Q

What is the specific gravity of exudate?

A

High specific gravity

41
Q

How is transudate different from exudate?

A

Transudate has low protein/albumin content and low specific gravity

Exudate has high protein/albumin content and high specific gravity

42
Q

What are some examples of different kinds of oedema?

A

Peripheral oedema

Pulmonary oedema

Lymphatic blockage

Oedema in abnormal renal function

Low protein oedema

Permeability oedema

43
Q

What is the pathophysiology of peripheral oedema?

A

1) Right heart failure means cannot empty right ventricle in systole
2) Blood retained in systemic veins, leading to increased pressure in capillaries
3) Causes increased filtration and peripheral oedema (also cause of secondary portal venous congestion in the liver)

44
Q

Is pulmonary oedema transudate or exudate?

A

Transudate (due to hydrostatic pressure)

45
Q

What is the pathophysiology of pulmonary oedema?

A

1) Left ventricular failure increases left ventricular pressure leading to passive flow to pulmonary veins, capillaries and arteries
2) Increased pulmonary vascular pressure
3) Increased pulmonary blood volume causing increased capillary hydrostatic pressure which leads to filtration and pulmonary oedema

46
Q

What happens in the lungs during pulmonary oedema?

A

Progressive oedematous widening of alveolar septa

Accumulation of oedema fluid in alveolar spaces

47
Q

What does lymphatic blockage lead to?

A

Upsetting the hydrostatic pressure

48
Q

What is lymphatic drainage required for?

A

Normal flow so it if is blocked it leads to lymphoedema

49
Q

What does lymphatic blockage lead to?

A

Lymphoedema

50
Q

What does abnormal renal function due to oedema result in?

A

Salt (NaCl) and water retention

51
Q

What is abnormal renal function secondary in?

A

Heart failure due to reduced renal blood flow

52
Q

What is abnormal renal function primary in?

A

Acute tubular damage such as in hypotension

53
Q

What is the pathophysiology of decreased renal function?

A

1) Increased salt and water retention
2) Increases intravascular fluid volume
3) Leads to increased capillary hydrostatic pressure causing oedema

54
Q

Is low protein oedema transudate or exudate?

A

Transudate

55
Q

What does capillary oncotic pressure require?

A

Normal protein levels

56
Q

What is a consequence of capillary oncotic pressure requireing normal protein levels?

A

Hypoalbumincaemia leads to decreased capillary oncotic pressure which increases filtration, leading to oedema

57
Q

What are examples of low protein oedema?

A

Nephrotic syndrome where leaky renal glomerular basement membrane causes a loss of protein and generalised oedema

Heaptic cirrhosis where diffuse nodules and fibrosis in the liver means it is unable to synthesise enough protein

Malnutrition due to insufficient protein intake

58
Q

Is permeability oedema transudate or exudate?

A

Endothelial permeability so exudate

59
Q

What is the pathophysiology of permeability oedema?

A

1) Damage to endothelial lining leads to increase in ‘pores’ in the membrane
2) Osmotic reflection coefficient of endothelium moves down towards 0
3) Proteins and larger molcules can leak out as well as water

60
Q

What are examples of permeability oedema?

A

Acute inflammation such as pneumonia

Burns

61
Q

Generally, what leads to oedema?

A

Upsetting starling forces that control filtration

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