Hemodynamic disorders

Question 1

what is oedema?

Answer 1

An abnormal increase in interstitial fluid

Question 2

What does Oedema mean?

Answer 2

• Increased hydrostatic pressure
• Salt and water retention
• Reduced plasma oncotic pressure
• inflammation
• lymphatic obstruction

(HSWOIL)

Question 3

What are the two types of oedema?

Answer 3

1. Localised oedema
2. Generalised oedema

Question 4

Describe generalised oedema

Answer 4

Fluid in serous cavities (pleural, pericardial, peritoneal)

more than 5L

Causes:

• heart failure
• inflammation
• venous hyoertension
• lymphatic obstruction

Question 5

Describe localised oedema

Answer 5

Pulmonary and cerebral oedema

Causes:

• Heart failure (congestive)
• Hypoproteinaemia (low protein content)
• Nutritional oedema (low albumin)

Question 6

What is generalised pitting oedema?

(difference between pitting and non-pitting)

Answer 6

When oedema occurs in subcutaneous tissues AND serous cavities.

Pitting oedema- when you apply pressure to swollen area (each a finger press), the impression will stay there, it will leave a pit.

Non-pitting oedema will return back to the swollen shape.

Question 7

What is pulmonary oedema?

Answer 7

In pulmonary capillaries, the oncotic pressure is greater than the hydrostatic pressure.

left heart failure increases the hydrostatic pressure in the pulmonary capillary bed

Fluid will accumulate first in the the interstitial space and then eventually spills into the alveolar spaces.

Question 8

What is this xray showing?

Answer 8

Pulmonary oedema.

You should be able to see clear black spaces for the lungs.

In the xray, the pt has an enlarged heart whcih suggests heart failure.

Fluid accumulates in the alveoli leading to almost no oxygen diffusion (which causes shortness of breath)

Question 9

Breathlessness and pulmonary oedema?

Answer 9

Breathlessness (dyspnoea) is the main symptom.

It is typically worse when lying flat (orthopnoea)

Fluid in the alveolar spaces predisposes to bacterial infection in the lungs (pneumonia).

The microscopic picture is an image of proteinaceous material within the alveoli

Question 10

What is cerebral oedema?

Answer 10

it is localised oedema. Caused by the following:

Vasogenic- increased permeability of capillaries and venules

Cytotoxic- derangement of sodium-potassium mebrane pumps e.g. ischaemic strokes

Question 11

What is thrombosis?

Answer 11

It is an abnormal blood clot formation in the circulatory system

Question 12

What are the three causes of thrombosis?

(Virchow’s triad)

Answer 12

1. endothelial injury (to the vessel wall)
2. Stasis or turbulent blood flow
3. Blood hypercoagulability- coagulation pathways are activated and thrombosis occurs

Question 13

what is venous blood flow?

Answer 13

Stasis and hypercoagulability are key factors. Most of the time they form in deep leg veins (venous thrombosis-DVT) Sometimes can occur higher up.

It can be caused genetically or acquired disruption in the lamina blood flow (e.g. long term bed rest)

Pulmonary embolism is the most important potential complication.

Question 14

What is arterial thrombosis?

Answer 14

Almost always related to vessel wall injury caused by atherosclerotic plaques.

Narrowing of the artery (stenosis) causes ischarmia of the tissue supplied bu the artery.

A complee blockage of the artery by thrombus causes infarction of the tissue supplied by the artery.

Question 15

Arterial thrombosis can cause real problems with the heart…

Answer 15

You can get red thrombus in a coronary artery leading to myocardial infarction.

Question 16

There are 4 different fates of thrombi

Answer 16

• Propagation
• Embolisation
• Dissolution (break down)
• Organisation and recanalisation (coronary artery)

(PEDRO!!)

Question 17

When do thrombi become noticable?

Answer 17

• When they obstruct arteries or veins
• When they embolise (obstruction of artery or vein with a clot)

Question 18

What is an emboli?

Answer 18

It is abnormal material within the circulatory system that is carried in the blood to a site distant from its point of origin. Most emboli are fragments of dislodged thrombus.

Rare types of emboli include: fat, air, amniotic fluid, tumour.

Emboli can lodge vessels and block them off

Question 19

What does ischaemia mean?

Answer 19

It describes something that has a lack of oxygen

Question 20

What does infarct mean?

Answer 20

It is an area of ischaemic necrosis caused by occlusion (blockage) to arterial or venous supply.

Question 21

What is the difference between a red infarct and white infarct?

Answer 21

Red infarct- venous occlusion happens in tissue with geocirculation like the lungs

White infarct- arterial occlusion- solid organ wedge shape- spleen or kidney.

Infarcts can heal by repair. Although structural integrity is maintained, there is a permenant loss of tissue

Question 22

What is bowel infarction?

Answer 22

Infarcted segment of small bowel is dark

Question 23

What is myocardial infarction?

Answer 23

Normal myocardium should not be so thick. the white areas are the areas of ischaemia- these areas have scarred.

Question 24

DVT and pulmonary embolism

Answer 24

Most venous thromoembolism originate from DVT.

Emboli that block the pulmonary artery is the most significant consequence.

Question 25

Seriousness of emboli in arteries?

Answer 25

• emboli lodging in major pulmoary artery can cause instantaneous death
• emboli lodging in medium sized arteries present with breathlessness.
• emboli lodging in small arteries cause subtle symptoms, breathlessness, chest pain and dizziness- these are the hardest to diagnose.

30% of pt with pulmonary embolism will die from it. The reisk of death increases the longer it takes to make the diagnosis.

Question 26

What is a haemorrhage?

Answer 26

Extravasation of blood due to vessel rupture.

May be due to trauma or an intrinsic disease of a vessel:

• amyloid (protein diposited in liver, kidneys and spleen)
• collagen vascular diseases

Rupture of major vessel causes acute haemorrhage with risk of hypovolaemia (decreased volume of blood travelling around the blood), shock and death

Question 27

Examples of haemorrhages

Answer 27

• Abdominal aortic aneurysm
• Brain stem haemorrhage
• Extravasation (leakage) of blood due to vessel rupture

Question 28

What are the characteristic symptoms of abdominal aortic aneurysm (triple A)?

Answer 28

back pain

hypotension

pulsatile mass

Question 29

What are the different types of shock?

Answer 29

Hypovolaemic shock (not enough volume in the blood)

Cardiogenic shock

Anaphylactic shock

Septic shock

Neurogenic shock

(CHANS)

Question 30

What is hypovolaemic shock?

Answer 30

Fluid loss

more than 1L of blood lost (more than 20%)

Most perfused organs are the kidney, brain and skin

Question 31

What is cardiogenic shock?

Answer 31

Heart cannot pump enough blood to meet the body’s demands- caused by acute myocardial infarction.

There is a high mortality rate

Question 32

What is septic shock?

Answer 32

Systematic inflammatory response syndrome

temperature above 38 or below 36

tachycardia- more than 90bpm

respiratory rate more than 20 breaths a min

WBC more than 12 x 10^9

Sepsis

SIRS + infection (systematic inflammatory response syndrome)

Severe sepsis

Sepsis + organ hypoperfusion

Question 33

severity of septic shock depends on the bacteria:

gram positive> gram negative> fungi

severe sepsis and hypoperfusion despite adequate fluid resuscitation, or the use of vasopressors/inotropes to maintain blood pressure.

Endotoxins released by pathogems- activate complement pathway, damage endothelial cells, tumour necrosis factor

Question 34

What are the general complications of septic shock?

Answer 34

organ dysfunction and multi-organ failure

ischaemic tissue- lactic acidosis

acute tubular necrosis