Cell Pathology 1 - Haemodynamic Disorders

Question 1

What is oedema?

Answer 1

An abnormal increase in interstitial fluid

Question 2

What are the aetiologies (causes) of oedema?

Answer 2

• Increased hydrostatic pressure
• Salt and H2O retention
• Reduced plasma oncotic pressure
• Inflammation
• Lymphatic obstruction

Question 3

What are the two types of oedema?

Answer 3

• Generalised oedema (fluids in serious cavities)

- Localised oedema (pulmonary and cerebral oedema)

Question 4

How much larger must the amount of interstitial fluid be for generalised oedema? Where is it found?

Answer 4

• > 5L

- Pleural, pericardial, peritoneal cavities

Question 5

What are the effects of generalised oedema?

Answer 5

• Left heart failure
• Inflammation
• Venous hypertension
• Lymphatic obstruction

Question 6

What can localised oedema cause?

Answer 6

• Congestive heart failure
• Hypoproteinaemia (low protein content)
• Nutritional oedema

Question 7

What is generalised pitting oedema?

Answer 7

• Widespread accumulation of fluid in subcutaneous cavities
• Pitting oedema is observable swelling of body tissues due to fluid accumulation that may be demonstrated by applying pressure to the swollen area (such as by depressing the skin with a finger).

Question 8

What is pulmonary oedema?

Answer 8

• Left heart failure increases the hydrostatic pressure in the pulmonary capillary bed
• Fluid accumulates first in the interstitial space and then spills into alveolar spaces

Question 9

What are the symptoms of pulmonary oedema?

Answer 9

• Breathlessness (dysponea)
• Breathlessness is worse when lying flat (orthopnoea)
• Fluid In alveolar spaces predisposes to bacterial infection in the lung (pneumonia)

Question 10

What is cerebral oedema?

Answer 10

• Localised oedema
• Vasogenic (increased permeability of capillaries and valves)
• Cytotoxic (derangement of sodium/potassium pumps for example in ischaemic strokes)

Question 11

What is thrombosis?

Answer 11

• Abnormal blood clot formation in the circulatory system

Question 12

What is virchows triad in thrombosis?

Answer 12

• Endothelial injury
• Stasis or turbulent blood flow
• Blood hypercoaguability

Question 13

What is venous thrombosis& and it’s possible complications?

Answer 13

• Stasis and hypercoagulability are key factors
• Form in deep leg vains mostly
• Pulmonary embolism is the most important potential complication

Question 14

What is arterial thrombosis? What are the potential complications?

Answer 14

• Related to vessel wall injury caused by atherosclerotic plaques
• Narrowing of the artery (stenosis) causes ischaemia of the tissue supplied by the artery
• Complete blockage (occlusion) causes infarction of the tissue supplied by the artery

Question 15

What are the fates of thrombi?

Answer 15

• Propagation (becomes larger)
• Embolism (small piece of clot breaks off)
• Dissolution (removed to allow normal blood flow)
• Organisation and recanalisation (body’s inflammatory response fixes the thrombi)

Question 16

When do thrombi come to clinical attention?

Answer 16

When they obstruct arteries or veins& or give rise to emboli.

Question 17

What is an emboli?

Answer 17

• Abnormal material within the circulatory system that is carried in the blood to a site distant from its point of origin
• Often dislodged thrombus
• May be fat& amniotic fluid or a tumour
• Can lodge in vessels and block them off

Question 18

What is an infarct?

Answer 18

• An area of ischaemic necrosis caused by occlusion
• Red infarct by venous occlusion
• White infarct by arterial occlusion
• Heal by repair (maintains structural integrity& but loss of functional tissue)

Question 19

What is a venous thromboembolism?

Answer 19

An embolism originating from deep veins

Question 20

What are the symptoms of a pulmonary thromboembolism?

Answer 20

• Emboli lodging in a major pulmonary artery - causing immediate death
• Emboli in medium arteries cause breathlessness
• Emboli in small arteries cause breathlessness& chest pain& and dizziness
• Risk of death increases the longer it takes to diagnose

Question 21

What is a haemorrage?

Answer 21

• Extravasion of blood due to vessel rupture (trauma/intrinsic disease of the blood vessel)
• Rupture of a major vessel causes acute haemmorage with risk of hypovolaemia& shock and death

Question 22

What are the types of shock?

Answer 22

• Hypovolemic
• Cardiogenic
• Anaphylactic
• Sepsis
• Neurogenic

Question 23

What is hypovolaemic shock?

Answer 23

• Due to fluid loss
• Loss of over 1L of blood
• Mostly affects kidney, brain and skin

Question 24

What is cardiogenic shock?

Answer 24

• Heart can’t pump enough blood to meet the body’s demands
• Caused by acute myocardial infarction
• High mortality rate

Question 25

What is septic shock?

Answer 25

Systematic inflammatory response syndrome + infection + organ hyperfusion despite fluid resuscitation, or use of vasopressors.

Question 26

What are the complications of sepsis?

Answer 26

• Organ dysfunction
• Multi-organ failure
• Ischemic tissue
• Acute tubular necrosis

Question 27

What causes septic shock?

Answer 27

Gram positive > gram negative > fungi

Release of endotoxins:

• Activates compliment pathway
• Damages endothelial cells
• Tumour necrosis factor