Fluid Pathology

Question 1

fluid distribution

Answer 1

2/3 water intracellular
1/3 extracellular

Question 2

oedema

Answer 2

change in distribution of fluid between plasma and interstitial
accumulation of excess interstitial fluid

occurs by:
- increased microvascular permeability
- increased intravascular hydrostatic pressure
- decreased intravascular osmotic pressire
- decreased lymphatic drainage

Question 3

microvascular permeability

Answer 3

3 types of endothelium - continuous, fenestrated, discontinuous
permeability increase by inflammation
inflammatory mediators –> release of cytokines –> endothelial cells retract and widen interendothelial gaps

Question 4

intravascular hydrostatic pressure

Answer 4

increased flow or volume of blood
hyperemia - active - eg blushing
congestion - passive - blood doesn’t flow properly, backflow into venous system, leakage of fluid into interstitium

Question 5

decreased intravascular osmotic pressure

Answer 5

colloidal pressure (osmotic) maintained by plasma proteins (albumin)
reduced albumin in plasma –> increased water filtration & decreased resorption because of gradient –> fluid into interstitium

Question 6

decreased lymphatic drainage

Answer 6

lymphatic obstruction or compression
congenital lymphatic aplasia
intestinal lympghangiectasia or lymphangitis (johne’s disease)

Question 7

effusions

Answer 7

same mechanism as oedema but into larger cavity rather than interstitium
abdomen - ascites
thorax - pleural effusion

Question 8

transudate

Answer 8

<2.5g/dL total protein
<1.5g/dL nucleated cells

usually due to decreased plasma osmotic pressire
hypoalbuminemia

Question 9

modified transudate

Answer 9

> 2.5g/dL total protein
<5g/dL nucleated cells

in response to increase hydrostatic pressure or permeability
cardiac disease, neoplasma, hepatic disease, and FIP

Question 10

exudate

Answer 10

> 4g/dL total protein
5g/dL nucleated cells

increased vascular permeability
inflammation, irritants, tissue necrosis, microorganisms