Lecture 10- Edema, congestion, hyperemia

what percent of the lean body weight is water

60%

what is the distribution of body water

66% intracellular

25% extracellular

8% of total body water in blood plasma

tissue well being also requires a normal

fluid balance

abnormalities in vascular permeability or hemostasis can result in

injury even with an intact blood supply

normal fluid homeostasis encompasses maintenance of

vessel wall integrity as well as intravascular pressure and osmolarity within certain physiologic ranges

what all affects the net movement of water across the vascular wall

changes in vascular volume, pressure, or protein content

Alterations in any of the factors which regulate

normal fluid distribution resulting in fluid

accumulation in the interstitium results in

edema

edema

increased fluid extravasation into interstitial/ extracellular spaces

what is edema easily recognized by

clear to yellow gelatinous material

where is edema and effusion found

subcutiss

brain

lungs

any tissue

how does edema manifest microscopically

as clearing and seperation of the intracellular matrix elements

what does effusion appear as

clear to yellow fluid

starling’s forces describes

movement of fluid between blood and tissues with hydrostatic and oncotic pressures being the major forces involved

push pressure

hydrostatic

pull pressure

oncotic

swollen

distended, tends to gravitate ventrally (sagging tissues)

tissue pits

indetations remain after pressure is removed

what temperature is edema usually to touch

cool

edema

effusion

edema

with edema what will be seen with lymphatic vessels of histology

will be dilated as they are the natural channel for removal of excess fluid

what prefix is added to indicated effusion

hydro

hydrothorax

fluid in pleural cavity

hydropericardium

fluid in pericardial sac

hydrosalpinx

fluid in uterine tube

hydrocephalus

accumulation of fluid in the brain

hydrocoele

fluid filled cyst anywhere in body

hydroperitoneum (ascites)

fluid in the peritoneal cavity

anasarca

severe and generalized edema, with profound SQ tissue swelling

non inflammatory effusion

transudate

protein levels of transudate

low

transudate

fluid accumulation due to hydrostatic imbalances between intravascular and extravascular compartments DESPITE normal vascular permeability

clear, colorless, or slightly yellow

modified transudate

• In-between where protein content is high but not as

high as with exudate

• Most common in FIP

inflammatory effusion is also known as

exudate

eudate

related to increased endothelial permeability

high protein levels

caused by leakage of plasma proteins (albumin) and leukocytes

usually opaque

transudate

exudate

intracellular edema

extra cellular edema

mechanisms of edema ***

increased microvascular permeability

increased intravascular hydrostatic pressure

decreased oncotic pressure

decreased lymphatic drainage

in increased microvascular permeability what does inflammation or endothelial damage result in

increased capillary permeability to fluids, salts, and colloids

during increased microvascular permeability inflammation results in release of

mediators to cause vasodilation

vasodilation results in

widening of the interendothelial gaps

water moves from ______ into _________

intravascular space into the interstitium

increased microvascular permeability manifest grossly as

edema/ effusion

venous obstruction or impaired venous outflow

• Results in increased hydrostatic pressure as blood

backs up in the venous system

• Causes leakage of sodium and fluid into the

interstitial tissue

• No significant leakage of colloids

main thing that occurs with increased intravascular hydrostatic pressure

venous obstruction or impaired venous outflow

mechanisms of increased intravascular hydrostatic pressure

• Increased blood flow = hyperemia

• Passive accumulation of blood = congestion

• Increased blood volume

increased intravascular hydrostatic pressure causes

congestive heart failure

cirrhosis of the liver

obstruction or narrowing of the veins

capillary blood contains a decreaed quantity of colloids due to

• Decreased hepatic synthesis of proteins

• Increased protein loss through the kidney or GI tract

what happens as a result of hypoproteinemia

fluid and sodium are not reabsorbed at the venous end of the capillary

• fluid accumulates in the interstitium as edema

decreased oncotic pressure causes

• Kidney disease

• Cirrhosis of the liver/liver failure

(hypoalbuminemia)

• Malnutrition/starvation

• Protein-losing gastroenteropathies or nephropathies

• Gastrointestinal parasitism

• Blood loss

decreased lymphatic drainage causes

Normally, small quantities of fluids, salts, and

colloids escape from capillaries and are drained

from the interstitium by lymphatics

why do lymphatic obstructions occur with decreased lymphatic drainage

these materials

accumulate because of the reduced ability of the

lymphatic system to remove excess fluid

decreased lymphatic drainage causes

• Inflammation

• Lymphatic vessel compression

(neoplasia or inflammation)

• Lymph vessel constriction (fibrosis)

• Lymph vessel blockage (thrombus or embolus)

• Post-surgical

• Post-irradiation

hyperemia

an active process resulting in increased tissue blood flow due to arteriolar dilation

excess blood of arterial origin

examples of hyperemia

skeletal muscles during exercise

at sites of inflammation

what color is hyperemia

red because of engorgement with oxygenated blood

hyperemia

congestion

a passive process resulting from impaired outflow from a tissue

interference with venous drainage

what might congestion interference with venous drainage be

systemic as in heart failure

local due to isolated venous obstruction

what color is congestion

red-blue (cyanosis) due to the accumulation of deoxygenated blood

congestion causes

• Heart failure (generalized slowing of blood everywhere)

• Left heart – lung most affected (chronic pulmonary congestion)

• Right heart – liver (chronic passive congestion)

• Venous occlusion (localized) – thrombus, pressure, twisting

• Hypostasis – hypostatic congestion

blood flow

active hyperemia

passive congestion

active hyperemia

passive congestion

hypostatic congestion

Blood pooling in organs and tissues on the lower side of a recumbent animal (contrast to livor mortis)

chronic passive congestion

Caused by disease that

results in right heart failure

chronic pulmonary congestion

Caused by any disease that

results in left heart failure

hyperemia

what occurs in the histology of hyperemia

• Arterioles and capillaries are dilated and filled with

blood (may appear more numerous)

• If the cause is inflammatory (usually is), other morphologic features of inflammation may also be present

• Inflammatory cells

• Necrotic cells

SQ tissue edema

transudate

locally extensive

severe

acute

notice that it is gelatin like

lungs: pleural edema, multifocal to locally extensive, severe, acute

thoracic cavity: thoracic effusion (or hydrotorax), diffuse, moderate, acute

exudative effusion

corneal edema

small intestine: mesenteric edema, locally extensive, mild, acute

lung: pulmonary edema, diffuse, severe, acute