2 - Haemodynamic disorders

Question 1

What causes pulmonary oedema?

What causes this?

Answer 1

raised hydrostatic pressure in the pulmonary capillary bed

this is caused by left ventricular failure
(increased pressure in the left atrium—> back pressure-volume in the capillaries—> pushes fluid into the interstitial space

Question 2

What is cardiogenic pulmonary oedema?

Answer 2

fluid accumulated in the interstitial space and spills over into the alveolar walls

Question 3

What is non-cardiogenic pulmonary oedema caused by?

Answer 3

increased permeability

Question 4

What is ARDS?

What are the most common causes?

What is the main symptom?

Answer 4

acute respiratory distress syndrome

causes: sepsis, shock, trauma

main symtom is dyspnea

Question 5

List the 4 types of cerebral oedema

Answer 5

• vasogenic
• cytotoxic
• osmotic
• interstitial

Question 6

What is a vasogenic cerebral oedema?

What are the causes?

Answer 6

physical breakdown of the blood-brain barrier

causes: trauma and tumours

Question 7

What is a cytotoxic cerebral oedema?

Answer 7

derangement of the sodium-potassium pump leads t o a build of intracellular sodium, causing intracellular oedema

common in ischaemic strokes

Question 8

What is an osmotic cerebral oedema?

What is the cause?

Answer 8

reduction in plasma osmolality

cause: SIADH (syndrome of inappropriate ADH secretion), which is commonly caused by small cell carcinoma

Question 9

What is an interstitial cerebral oedema?

What is the cause?

Answer 9

breakdown of the CSF-brain barrier

cause: obstructive hydrocephalus
CSF moves into the interstitial space

Question 10

What is anasarca?

Answer 10

sever generalised oedema

Question 11

Define generalised oedema?

Answer 11

the widespread accumulation of fluid in subcutaneous tissue and serous cavities

Question 12

Define thrombosis

Answer 12

an abnormal blood clot formation in the circulatory system

Question 13

What often causes vessel war injury?

Answer 13

atherosclerotic plaques

Question 14

What is a stenosis?

What does it cause?

Answer 14

narrowing of an artery by the thrombus

causes ischaemia

Question 15

What is an occlusion?

What does it cause?

Answer 15

complete blockage of an artery by a thrombus

causes infarction of the tissue supplied by the artery

Question 16

Define embolism

Answer 16

a detached intravascular solid, liquid or gaseous mass that is carried by the blood to a site distant form its point of origin

most are thromboemboli (fragments of dislodged thrombus)

Question 17

What are the other types of embolic material?

Answer 17

• fat
• air
• amniotic fluid
• tumour

Question 18

Where do venous thromboemboli originate from and what is the major consequence?

Answer 18

most originate from the deep veins (DVT)

major consequence is pulmonary (thrombosis)embolism

Question 19

Why is there a range of consequences of pulmonary thromboemboli?

Answer 19

consequence depends on the size and where it becomes lodged

e.g. emboli lodging in a major pulmonary artery will cause instantaneous death

Question 20

What is a saddle embolus?

Answer 20

one that becomes lodged at the bifurcation of the pulmonary trunk

Question 21

What are the symptoms when a pulmonary embolism lodges in a middle sized artery?

Answer 21

breathlessness

Question 22

Where do arterial thromboemboli originate from and what can it cause?

Answer 22

originate from carotid arteries

most likely to affect cerebral arteries and cause stroke

Question 23

Where do cardia thromboemboli originate from?

Where can it lodge and what are the consequences?

Answer 23

originate from the left side of the heart
can lodge in:
- cerebral artery= stroke
- mesenteric artery= bowel infarction
- lower limb artery= acute lower limb infarction

Question 24

Define haemorrhage

Answer 24

extravasation of blood due to vessel rupture

can be external or enclosed within a tissue

Question 25

What are the causes of haemorrhage?

Answer 25

trauma

intrinsic disease of the vessel

Question 26

How are haemorrhages classified?

Answer 26

based on their size

Question 27

What can be the result or a solid haematoma within the cranial cavity?

Answer 27

can be fatal

causes a rise in ICP and (tonsillar) herniation

Question 28

When does shock occur?

Answer 28

when tissue perfusion is insufficient to meet the metabolic demand

Question 29

Give the equation for mean arterial pressure

Answer 29

MAP = CO x SVR

Mean arterial pressure = cardiac output x systemic vascular resistance (total peripheral resistance)