Fluid Distribution and Edema

Question 1

What are some causes for the loss of isotonic fluid from the body?

Answer 1

hemorrhage
diarrhea
vomiting

Question 2

What are some reasons for loss of hypotonic fluid from the body?

Answer 2

dehydration
DI
alcoholism

Question 3

What are some reasons for the gain of isotonic fluid in the body?

Answer 3

isotonic saline

Question 4

What are some causes for the gain of hypotonic fluid in the body?

Answer 4

hypotonic saline
water intoxication
SIADH

Question 5

What are some reasons for gain of hypertonic fluid in the body?

Answer 5

hypertonic saline
hypertonic mannitol

Question 6

What are some reasons for loss of hypertonic fluid?

Answer 6

adrenal insufficiency

Question 7

Can urea cross cell membranes?

Answer 7

yes

Question 8

2 primary factors for stimulating aldosterone release?

Answer 8

1. plasma Ang II
2. Plasma K+

Question 9

What are the primary regulators of ADH secretion?

Answer 9

1. plasma osmolality (directly) related
2. Blood pressure/ volume (inversely related)

Question 10

What are the primary regulators of renin release?

Answer 10

1. perfusion pressure to the kidney (inversely related)
2. sympathetic stimulation to the kidney (direct effect via B-1 receptors)
3. Na+ delivery to the macula dense (inversely related)

Question 11

Besides plasma osmolality and bp what are other factors that can regulate secretion of ADH?

Answer 11

CRH (stressors)
Ang II

Question 12

Filtration.

Answer 12

movement of fluid from plasma into interstitium

Question 13

Absorption

Answer 13

movement of fluid from interstitial into plasma

Question 14

What is the starling equation.

Answer 14

Qf = k[(Pc + πif) - (Pif + πc)]

filtration(+) - absorption(-)

Question 15

What is non-pitting edema?

Answer 15

when there is edema but visual indentation is absent when pressing on the affected

Question 16

What are some causes of increasing capillary hydrostatic pressure( Pc)

Answer 16

1. Marked increase in BF (eg. vasodilation in a given vascular bed)
2. increase in venous pressure (e.g venous obstruction or heart failure)
3. elevated blood volume which is typically caused by sodium retention

Question 17

What is increased πif usually caused by?

Answer 17

thyroid dysfunction (elevated mucopolysaccharides in the interstitium ) but can also be the result of lymphedema

Question 18

Increase πif can lead to what?

Answer 18

fluid accumulation and edema

Question 19

Decreased vascular oncotic pressure can be caused by what? (πc)

Answer 19

liver failure and nephrotic syndrome

Question 20

Increased capillary permeability can be caused by what? (k)

Answer 20

circulating agents like TNF-alpha, bradykinin, histamine, cytokines

Question 21

What can cause lymphatic obstruction?

Answer 21

filarial W Bancrofti, bacterial lymphangitis (strep), trauma, surgery, tumor

Question 22

Which is the most common cause of pulmonary edema, cardiogenic or non -cardiogenic?

Answer 22

cardiogenic

Question 23

What is an example of non-cardiogenic cause of pulmonary edema?

Answer 23

ARDS adult respiratory distress syndrome

increased permeability

Question 24

Characteristic of cardiogenic related pulmonary edema? Patient signs and symptoms. Best way to confirm?

Answer 24

elevated Pc

Increased left atrial pressure increases venous pressure which in turn inc. capillary pressure

First signs are orthopnea (dyspnea when supine) which can be relieved when sitting upright

Can be measured using pulmonary wedge pressure

Question 25

Treatment for cardiogenic cause of pulmonary edema?

Answer 25

reduce left atrial pressure (e.g. diuretic therapy)

Question 26

What are characteristics of non-cardiogenic pulmonary edema? What is it caused by? Clinical signs, etiology?

Answer 26

due to direct injury of the alveolar epithelium or after primary injury to capillary endothelium.

presence of protein containing fluid in the alveoli inactivates surfactant causing reduced lung compliance

Clinical signs: severe dyspnea of rapid onset, hypoxemia, diffuse pulmonary infiltrates leading to respiratory failure

Etiology: sepsis, bacterial pneumonia, trauma, gastric aspirations

Question 27

Describe pulmonary wedge pressure in non cardiogenic edema.

Answer 27

is normal or low

Question 28

How can you measure volume of a compartment (formula)?

Answer 28

VOC= amount of tracer/concentration of tracer in the compartment to be measured

Question 29

What are the best tracers used to measure plasma?

Answer 29

tracer not permeable to capillary membranes (e.g albumin) dextran in saline, whole blood

Question 30

What are the best tracers used to measure ECF?

Answer 30

tracer permeable to capillary membrane but not cell membrane (e.g inulin, mannitol, sodium, sucrose)

Question 31

What are the best tracers used to measure total body water?

Answer 31

tracer permeable to capillary and cell membranes (e.g tritiated water, urea) D5W 5% dextrose in water

Question 32

What is the formula for blood volume?

Answer 32

plasma volume/1-hematocrit

Question 33

Be able to draw out the basics metabolic panel.

Answer 33

4 boxes to the left measured in mEQ/L, mmol/L, mM and 3 to the right are mg/dl = mg%

Question 34

What is osmolar gap? What is normal osmolar gap?

Answer 34

difference between the measured osmolality and the estimated osmolality.

(normal ≤ 15)

Question 35

What is the formula for ECF estimated osmolality?

Answer 35

2(Na+) mEq/L + glucose mg%/18 + urea mg%/2.8