disorders of sodium balance

Question 1

volume status is dictated by the _____ in the body

Answer 1

content of sodium

Question 2

volume contraction is a disorder of

Answer 2

sodium depletion

Question 3

volume expansion is a disorder of

Answer 3

sodium overload

Question 4

kidneys modify sodium handing according to the

Answer 4

perceived volume status- effective circulating volume

Question 5

sodium retention occurs under circumstancces of

Answer 5

volume depletion

Question 6

sodium excretion occurs under circumstances of

Answer 6

volume overload

Question 7

sodium balance affects

Answer 7

volume status

Question 8

water balance affects

Answer 8

plasma osmolality and sodium concentration

Question 9

sensors that assess volume status

Answer 9

1. afferent arteriole
2. macula densa
3. carotid/ aortic bodies
4. cardiac chambers

Question 10

blood pressure fall leads to the activation of

Answer 10

RAAS system

Question 11

factors that stimulate renin secretion from JG

Answer 11

1. decreased chl- delivery to macula densa
2. decreased perfusion of JGA
3. B1 sympathetic stimulationof JGA

Question 12

actions of angiotensin II

Answer 12

1. vasoconstriction of the systemic arterioles and efferent arterioles
2. aldosterone release
3. renal sodium retention through direct stimulation of sodium reabsorption in the PCT and enhancing sodium reabs. in CT mediated by aldosterone

Question 13

factos stimulating aldosterone synthesis

Answer 13

1. Angiotensin II

2. hyperkalemia

Question 14

actions of aldosterone at the renal cortical collecting tubule

Answer 14

1. increased sodium reabs
2. enhanced potassium secretion
3. increased hydrogen secretion

Question 15

factors that stimulate SNS

Answer 15

decreased pressure at nerve plexi bodies in carotid arteries and aortic arch

Question 16

actions of SNS

Answer 16

1. sympathetic vasoconstriction
2. renal sodium retention- direct stimulation pf PCT Na reabs
3. efferent arteriolar vasoconstriction
4. stimulation of renin release

Question 17

factos that stimulate ANP from atria

Answer 17

increased atrial stretch

Question 18

actions of ANP

Answer 18

1. increased renal Na excretion- direct on CT

2. at higher doses is a vasodilator and can increase RPF and GFR

Question 19

blood pressure is associated with which pressure

Answer 19

Pgc

Question 20

in volume overload, where there is a higher GFR and thus a faster tubular flow rate what happens?

Answer 20

there is a shorter tubular transit time thus reabs of Na decreases and there is more loss of it in the urine

the whole purpose it to correct volume overload

Question 21

volume depletion is diagnosed by

Answer 21

clinical symptoms!!!!!!!!

• decreased BP
• tachy
• decreased skin turgor
• orthostasis
• decresed JVP

Question 22

characteristic lab and urine tests in volume depletion

Answer 22

• reduced GFR
• low urine Na
• increased BUN/Cr ration
• low Fractional Excretion of Na (FENa)

Question 23

what is FENa?

Answer 23

excreted load of Na / filtered load of sodium

Question 24

when do we expect to see a low FENa?

Answer 24

at times of volume depletion and there is an activation

Question 25

true or false: host response to ineffective perfusion is the same as the response to volume depletion

Answer 25

yep

Question 26

true or false: we can measure the effective circulating volume

Answer 26

nope

Question 27

volume overload diagnosis made by

Answer 27

clinical symptoms!!!!! - pulmonary edema - peripheral edema

Question 28

characteristics we see with volume overload

Answer 28

- elevated BNP - high urine Na+ - high FENa

Question 29

which diseases are associated with volume overload but there is still stimulus for sodium retention

Answer 29

1. heart failure 2. cirrhosis 3. Nephrotic syndrome

Question 30

underfill hypothesis 1

Answer 30

movement of fluid into intersittium triggers retention (via RAAS and SNS) in attempt to expand extracellular volume and restore tissue perfusion

Question 31

overflow hypothesis 2

Answer 31

sodium retention by the kidney leads to expanded extracellular volume and results in fluid movement out of capillaries and into interstitium

Question 32

edema formation is from 4 mechanisms

Answer 32

1. increased capillary pressure due to increased venous pressure either by venous obstruction or expanded venous blood volume 2. decreased plasma oncotic pressure such as in hypoalbuminemia 3. increased capillary permeability 4. lymphatic obstruction

Question 33

how do we treat cirrhosis

Answer 33

treating the hemodynamic dysregulation and splanchnic vasodilation adn reducing extracellular volume

Question 34

nephrotic syndrome

Answer 34

poorly characterized impairment of sodium excretion precedes the underfilled state due to heavy albumin loss in the urine

Question 35

treatment of nephrotic syndrome

Answer 35

decreased Pgc with ACEi and AII blockers

Question 36

ineffective circulating volume leads to inadequate renal perfusion which causes sodium rentetion by the kidney leading to an overall volume overload this is the common pathway where these four diseases/states converge

Answer 36

1. Heart failure- low cardiac output 2. marathon- true volume depletion 3. cirrhosis- Drop in SVR 4. Nephrotic syndrome- hypoalbunemia resulting in extra-vascular pooling

Question 37

treatment of volume disorders require

Answer 37

managing sodium balance and renal perfusion

Question 38

FeNa is often a good indicator of the ______ as the kidney retains Na when it is underperfused and released Na when it is well perfused

Answer 38

effective circulating volume

Question 39

HF results in volume overload by

Answer 39

reducing cardiac output, lowering renal perfusion, and stimulating Na retention.

Question 40

Cirrhosis results in volume overload by

Answer 40

dropping plasma oncotic pressure (through impaired albumin synthesis).

Question 41

Arteriovenous malformations in cirrhosis also drop SVR and BP, leading to

Answer 41

renal underperfusion and Na retention.

Question 42

In nephrotic syndrome, protein loss in the urine lowers plasma oncotic pressure and intravascular volume, stimulating .

Answer 42

renal Na retention

Question 43

Volume overload is sensed by the cardiac chambers which release atrial __________ to block sodium reabsorption in the CT.

Answer 43

natriuretic peptide (ANP)