Haemodynamic disorders Flashcards Preview

*MCD Cell Pathology Y1* > Haemodynamic disorders > Flashcards

Flashcards in Haemodynamic disorders Deck (21)
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1
Q

What is oedema?

A

Abnormal increase in interstitial fluid

2
Q

Describe the pressures in tissues:

A

At arterial end, hydrostatic pressure > oncotic pressure.
- Fluid leaves circ
At venous end, oncotic pressure > hydrostatic pressure.
- Fluid re-enters venule

3
Q

What are the aetiologies of oedema?

A

Increased hydrostatic pressure - impaired venous return / heart failure

Salt/H2O retention - protein losing enteropathy/glomerulonephritis etc.

Reduced plasma oncotic pressure

Inflammation - sepsis or localised

Lymphatic obstruction - accumulation of fluid

4
Q

What is generalised oedema?

A

In serous cavities, >5L; caused by left heart failure (that then causes right heart failure), inflammation, venous hypertension or lymphatic obstruction (after radiotherapy/surgery)

5
Q

What is Generalised pitting oedema?

A

Widespread accumulation in subcutaneous tissue e.g. In feet as gravity draws down - causes pits when pressure applied

6
Q

What is localised oedema?

A

Pulmonary and cerebral; caused by congestive heart failure (L&R), low protein content or nutritional oedema

7
Q

What is pulmonary oedema?

A

Normally plasma oncotic pressure > hydrostatic pressure in pulmonary capillaries, but left heart failure increases hydrostatic pressure in pulmonary capillary bed, so fluid accumulates in interstitial and then alveolar space

8
Q

What are the symptoms of pulmonary oedema?

A

Dyspnoea (breathlessness), worse when lying flat

9
Q

What an pulmonary oedema lead to?

A

Fluid in alveolar spaces predisposes to bacterial infections (pneumonia)

10
Q

What is cerebral oedema?

A

Midline shift can occur; two causes: cytotoxic (derangement of Na+/K+-ATPase pumps) and vasogenic (increased permeability of capillaries and venules)

11
Q

What is a thrombosis?

A
Abnormal clot ofrmation caused by:
-endothelial injury
-stasis/turbulent flow
-hyprcoadulability
(Virchow's triad)
12
Q

What are the 4 fates of thromboses?

A

Propagation (get bigger)
Embolise
Dissolve
Organise and recanalisation

13
Q

What is an embolus?

A

Abnormal material within circulatory system carried to site distant from origin; most fragments of a dislodged thrombus (thromboemboli) but can be caused by fait, air, tumours or amniotic fluid; can lodge in larger vessels and block them off

14
Q

What is an infarct?

A

Area of ischaemic necrosis caused by the occulsion of arterial supply or venous drainage

15
Q

What is a Red infarct?

A

Caused by venous occlusion - organs w/dual circulation

16
Q

What is a white infarct?

A

Caused by arterial occlusion - solid organs (spleen, kidneys)

17
Q

Describe the repair of infarcts:

A

Fibrosis instead of original cells; preserves structural integrity, but permanent loss of functional tissue

18
Q

What triad signals a ruptured AAA

A

Back pain
Hypotension
Pulsatile mass

19
Q

What syndrome predisposes you to a AAA?

A

Marfans

20
Q

What is hypovolaemic shock?

A

More than 1L blood loss, most perfused organs will shut down

21
Q

What is cardiogenic shock?

A

Heart cannot pump enough blood to meet demands, caused by acute MI