Fluid and Hemodynamic Disorders

Question 1

Edema

Answer 1

Excess fluid in tissues

Can be localized or systemic

Question 2

Capillary hydrostatic pressure

Answer 2

Pressure in the capillary due to heart pumping and weight of blood

Question 3

Capillary oncotic pressure

Answer 3

Pressure in the capillary due to proteins present in fluids (proteins in blood cannot cross a normal capillary wall)

Question 4

Lymphatic system

Answer 4

A network of vessels separate from blood circulation that carries lymphatic fluid

Question 5

Albumin

Answer 5

Maintains oncotic pressure
Made by the liver
Transports steriods, thyroid hormone, bilirubin, bile salts, fatty acids

Question 6

Two main drivers of fluid movement across capillary wall:

Answer 6

Capillary hydrostatic pressure

Capillary oncotic pressure

Question 7

Pericyte

Answer 7

Vascular supportive cell

Question 8

How does the lymph fluid enter circulation?

Answer 8

Through the thoracic duct and right lymphatic duct

Question 9

3 causes of localized edema

Answer 9

1. Ischemia (irreversible cell injury): lysed cells release chemical mediators that cause leaky capillaries
2. Infection: white blood cells release chemical mediators that cause leaky capillaries
3. Lymphatic obstruction: obstruction or damage of small or large lymphatic vessels, usually by treatment for carcinoma

Question 10

2 ways capillaries become leaky

Answer 10

1. Endothelial cell retraction: ECs retract from each other in response to chemical mediators (can be reversible)
2. Endothelial cell injury: more severe damage results in endothelial cell necrosis and detachment (not reversible)

Question 11

3 causes of systemic edema

Answer 11

1. Heart failure: left = lungs, right = legs
2. Kidney disease: loss of albumin in urine, so retention of sodium and water
3. Liver failure: not enough albumin produced

Question 12

Ascites

Answer 12

Accumulation of fluid in the abdomen

Question 13

How does heart failure cause systemic edema?

Answer 13

Increased hydrostatic pressure from impaired venous return

Question 14

Heart failure

Answer 14

Heart is unable to pump enough blood to adequately perfuse tissues
Fluids will back up according to which ventricle is more affected

Question 15

Left heart failure

Answer 15

Left ventricle is not working properly
Blood backs up into pulmonary veins
Right heart is still working
Blood has trouble moving through the capillary bed, so increased pressure on the venous end = less fluid leaves vessels
Can hear crackles with stethoscope at base of lungs

Question 16

Right heart failure

Answer 16

Right ventricle is not functioning properly
Blood backs up into the vena cava
Problems arise in the capillary beds of the body
Increased hydrostatic pressure on the venous ends = no fluid moves
Patients can get ulcers from poor circulation
Treat with medications

Question 17

Pitting edema

Answer 17

Pressing on skin will leave an indentation

See in RV failure

Question 18

How does kidney disease cause edema?

Answer 18

In diseases kidneys, the glomerular basement membrane is damaged and albumin can cross it and be released into urine
Low blood concentration of albumin
Causes fluid to enter tissues and results in systemic edema
Oncotic pressure decreased, but hydrostatic pressure the same

Question 19

2 things in liver failure

Answer 19

Not producing enough albumin

Not producing enough clotting factors

Question 20

Why does liver failure cause edema?

Answer 20

Doesn’t produce enough albumin, so concentration is too low
Results in low oncotic pressure
Fluid will not return to capillary and will accumulate in tissues

Question 21

2 main proteins in the coagulation cascade

Answer 21

Thrombin

Fibrin

Question 22

Thrombo-embolus

Answer 22

A piece of thrombus that has broken off from where it formed and has travelled elsewhere in the body

Question 23

3 major components that control thrombus formation

Answer 23

Endothelial cells: damaged endothelial cells cause platelets to adhere and form a plug
Platelets: aggregate and form a plug
Coagulation cascade: thrombin cleaves fibrinogen into fibrin which stabilizes the platelet plug

Question 24

3 things pathologic thrombi can be caused by

Answer 24

1. Endothelial cell injury
2. Poor blood flow
3. Hypercoagulable state

Question 25

How does atrial fibrillation cause arterial thrombi?

Answer 25

Uncoordinated chaotic contraction of atrium results in areas of irregular blood flow
Thrombus can form on sites of poor blood flow in atrium
Often form on the surface of the left atrial appendage

Question 26

2 major causes of arterial thrombi

Answer 26

Atherosclerosis

Atrial fibrillation

Question 27

4 causes of venous thrombi

Answer 27

Venous stasis
Cancer
Pregnancy
Inherited Thrombophilia

Question 28

How can pregnancy cause venous thrombus?

Answer 28

Pro-coagulant changes of pregnancy likely part of physiologic preparation for delivery (to prevent excessive hemorrhage during delivery)

Question 29

How does inherited thromhophilia cause venous thrombus?

Answer 29

Some patients have genetic abnormalities in coagulation proteins that make them much more susceptible to venous thrombosis

Question 30

Shock

Answer 30

Circulatory failure that results in poor tissue perfusion resulting in cellular hypoxia

Question 31

3 ways to get shock

Answer 31

Cardiogenic shock: MI, other heart pathology
Hypovolemic shock: trauma (blood loss)
Septic shock: associated with systemic inflammatory response, usually infection (causes dilation of vessels)

Question 32

Acute Respiratory Distress Syndrome

Answer 32

Damage to pulmonary capillary endothelium and alveolar epithelium causes edema to enter pulmonary alveoli
Damage secondary to many things
Common in patients with shock
Other causes: aspiration, pancreatitis, smoke of toxic gas inhalation
Acute phase: alveolar edema
Later phases: progression to hyaline membranes and thickened alveolar walls

Question 33

Disseminated Intra-Vascular Coagulation

Answer 33

Complication of shock caused by excessive activation of coagulation and formation of thrombi in microvasculature of body
Causes consumption of coagulation factors and platelets and can then result in bleeding in other parts of the body
Ex: DIC in brain and kidneys and bleeding in GI tract