Week 6, Lec 2 Flashcards
what is edema
excess fluid in interstitial spaces
causes of edema
▪ blood hydrostatic pressure increase (arterial or venous)
▪ drop in blood oncotic pressure
▪ increased vascular permeability
▪ blockage of lymphatic flow
transudate vs exudate for edema fluid
transudate= low in protein
exudate= high in protein
transudate
transudate - edema fluid that is low protein, low cellular content, caused by pressure imbalances.
exudate
edema fluid (typical of inflammation) - High protein, high cellular content, caused by inflammation and vessel damage.
what is cause of transudate vs exudate
transudate from pressure imbalances
exudate from inflammation and vessel damage
what are starling forces
- Describe the movement of fluid across capillary walls
- Explains how fluid moves between blood vessels and surrounding tissues.
what do starling forces balance
between two pushing forces (hydrostatic pressures) and two pulling forces (oncotic pressures).
starling forces variables in equation
leakiness of capillary wall, hydrostatic pressure, osmotic pressure, fluid in capillary, fluid in interstitial space, how much protein leaks through capillary wall
what is oncotic pressure
the pull force that draws water into the blood vessels. Mainly created by large proteins.
what is hydrostatic presure
the push force that moves water out of the blood vessels into the surrounding tissues. It is generated by the pressure of the blood against the walls of the vessels, especially in the arteries.
hydrostatic pressure vs oncoticc pressure; which is push force and which is pull force
hydrostatic- push
oncotic- pull
4 things that can cause ederma
- increased hydrostatic pressure (arteriolar dilation, increased venous pressure, hypervolemia)
- decreases oncotic pressure (hypoproteinemia)
- increased capillary permeability
- lymphatic obstruction
disorders that are associated with edema
venous thrombosis, congestive heart failure, ascites, inflammation, post surgical lymphedema, malnutrition, nephrotic syndrome etc.
which is higher in arteries; oncotic pressure or hydrostatic pressure
hydrostatic pressure > oncotic pressure
which is higher in veins; oncotic pressure or hydrostatic pressure
oncotic pressure > hydrostatic pressure
which is higher for veins and for arteries; oncotic pressure or hydrostatic pressure
veins: oncotic pressure > hydrostatic pressure
arteries: hydrostatic pressure > oncotic pressure
in arteries since hydrostatic pressure > oncotic pressure then where is fluid driven into
interstitituim (surrounding tissue)
in veins since oncotic pressure > hydrostatic pressure then where is fluid go
filtered fluid is recaptured by osmosis, any excess is recovered by the lymphatic system
describe the starling forces in the arteries
- Pc (Capillary hydrostatic pressure) is higher than πc (Capillary oncotic pressure).
- This means that the force pushing fluid out of the capillary (Pc) is stronger than the force pulling fluid back into the capillary (πc).
- As a result, fluid is driven into the interstitium (surrounding tissue). This fluid helps nourish tissues.
describe the starling forces in the veins
- The capillary oncotic pressure (πc), driven by proteins like
albumin, pulls fluid back into the capillary from the
interstitial space - Not all fluid reenters the capillary; some excess fluid is
absorbed by the lymphatic system to prevent tissue swelling (edema).
4 causes of edema
- increased hydrostatic pressure
- increased sodium and water retention
- reduced lympahtic drainage
- decreased oncotic pressure
- damage to the endothelium or just excessive leakiness can obviously lead to edema
example of increased hydrostatic pressure
malignant hypertension
where extreme increases in blood pressure overwhelm the normal balance of fluid movement across the capillaries.
what is increased hydrostatic pressure causes by
can be caused by a generalized global increase in arteriolar blood pressure
what endocrine cause can increase hydrostatic pressure
excess levels of aldosterone, ADH, angiotensin II, and catecholamines
a decrease in what can increase hydrostatic pressure
Decreased venous drainage which can be regional (i.e. a single obstructed vein) or global (i.e. congestive heart failure) can increase hydrostatic pressure
endocrine causes of increased sodium and water retention
- syndrome of inappropriate ADH secretion
- adrenal cortical pathologies – too much aldosterone
what pathologies can impair sodium elimination
kidneys (i.e. decreased perfusion)
2 main things that can cause reduced lymphatic draingage
- malignancies
- surgeries
▪ malignancies that infiltrate
the lymph nodes
▪ surgeries that resect the lymph nodes
rare cause of reduced lymphatic drainage
▪ Rarely infections that cause intense fibrosis of lymph nodes and their channels
* infestation by a parasitic organism – filiariasis
What plasma protein is most responsible for blood oncotic pressure?
albumin
what is nephrotic syndrome
excess leakage of protein from the glomerulus (renal capillary complex)
- Protein filters from blood, through glomerular capillary –> protein enters the renal tubules and is excreted in the urine –> decreased oncotic pressure
causes of decreased oncotic pressure
nephrotic syndrome
hepatic failure
protein losing enteropathies or malnutrition
where is edema most noticable
areas inferior to the heart
renal diseases can cause
generalized edema that is apparent in areas that contain “looser” connective tissue
anasarca is
generalized edema
most severe forms of edema
pulmonary and brain edema
Unique features of the interaction of the microvasculature and air spaces (lungs) and the inflexible cranial cavity (brain) result in more severe consequences
anasarca
refers to severe, generalized edema, which is the widespread swelling of the body due to the accumulation of excess fluid in the interstitial spaces. It can affect various parts of the body, including the limbs, abdomen, and face.
angioedema
s a condition characterized by the rapid swelling of the deeper layers of the skin and mucous membranes, often affecting areas such as the face, lips, tongue, throat, and sometimes the abdomen. It is similar to hives (urticaria) but occurs in deeper tissues.
hyperaemia and congestion are both from
locally increased blood volume
what is hyperemia
arteriolar dilation (e.g., at sites of inflammation or in skeletal muscle during exercise) leads to increased blood flow
what happens to tissue in hyperaemia
affected tissues turn red (erythema) because of the engorgement of vessels with oxygenated blood
example of hyperemia
Example is the return of blood flow to tissue that is warming after being out in the cold
congestion
a passive process resulting from reduced outflow of blood from a tissue (sometimes called passive hyperemia)
hyperemia vs congestion
hyperemia= arteries dilate
congestion= passive hyperemia
types of congestion
can be systemic (heart failure) or local (venous obstruction)
what do tissues look like in congestion
▪ Congested tissues take on a dusky reddish-blue color (cyanosis) due to red cell stasis and the accumulation of deoxygenated
▪ Eventually red blood cells can extravasate, causing hemosiderin deposition in tissues
what is hemosiderin
degradation product of hemoglobin found mostly within macrophages
hyperaemia vs congestion
Hyperemia: Increased blood flow due to arteriolar dilation, typically resulting in a healthy, oxygen-rich appearance; often temporary.
Congestion: Blood pooling due to impaired venous outflow, often leading to a darker appearance and potential tissue damage; usually more chronic.
chronic passive congestion (long-standing congestion) is from
Stasis of poorly oxygenated blood causes chronic hypoxia
effects of chronic passive congestion
▪ Result in degeneration or death of cells and tissue fibrosis
▪ Capillary rupture at sites of chronic congestion → small foci of hemorrhage
▪ phagocytosis and catabolism of erythrocyte debris → Accumulations of hemosiderin-laden macrophage
acute vs chronic pulmonary congestion
▪ Acute: Alveolar capillaries engorged with blood
▪ Chronic: Septa become thickened and fibrotic
chronic pulmonary congestion
Septa become thickened and fibrotic
- Alveolar spaces contain hemosiderin-laden macrophages (“heart failure cells”)
acute hepatic congestion
Hepatocytes degenerate, sinusoids and
venules are distended with blood
* Those near the hepatic artery circulation undergo less severe hypoxia and develop fatty change
in congestive failure what appearance does the liver have
nutmeg appearance
causes of pulmonary venous congestion
left heart failure, mitral stenosis or regurgitaation
appearance of pulmonary venous congestion
Engorgement of pulmonary capillaries and venules, alveolar edema, heart failure cells, brown induration
clinical features of pulmonary venous congestion
Shortness of breath (dyspnea), wheezing, difficulty breathing with lying flat (orthopnea)
causes of hepatic venous congestion
Right heart failure, constrictive pericarditis
appearance in hepatic venous congestion
Enlarged liver, centrilobular necrosis, nutmeg liver
clinical features in hepatic venous congestion
Right upper abdominal pain, elevated liver enzymes, ascites, peripheral edema, jugular venous distension
causes of deep vein venous congestion
Blood clot formation (DVT), incompetent valves