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Old 03-20-2012
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Question Pathophysiologic status of this hyponatremic edema!

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A 60-year old woman has increasing fatigability, SOB, and ankle swelling. She also has experienced a gradual weight gain despite no change in eating habits. A physical exam shows bilateral pitting edema. Lab studies show decreased serum concentration of Na+. Which of the following is most likely?

A. Cardiac ejection is normal
B. Extracellular and intracellular fluid volumes are above normal
C. SIADH
D. Total body water is decreased
E. Venous hydrostatic pressure is decreased

(please explain your choice).
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Old 03-20-2012
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i think its B...........
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C. SIADH, volume overload, dilution hyponatremia
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C.............
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its c
small cell ca of lung ...secreting ectopic ADH....causing increased retention of fluid...

this s a typical usmle question
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Old 03-20-2012
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looks like C....
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Default Answer = b

the answer is B

i also had selected C.
Can anybody figure out why B? @bunny.
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Old 03-20-2012
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no idea....can only think of dilutional hyponatremia in SIADH.....
Quote:
Originally Posted by Dr.NickRiviera View Post
the answer is B

i also had selected C.
Can anybody figure out why B? @bunny.
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The question says gradual weight gain it can't be cancer

question states PITTING EDEMA. This is a concept question asking about how piiting edema occurss???

Like the thingee u rememer from kaplan a very absurd equation of intracellular and extracellullar oncotic and hydrostatic pressure.

I just thought that way thru this question.
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Quote:
Originally Posted by bunny View Post
The question says gradual weight gain it can't be cancer

question states PITTING EDEMA. This is a concept question asking about how piiting edema occurss???

Like the thingee u rememer from kaplan a very absurd equation of intracellular and extracellullar oncotic and hydrostatic pressure.

I just thought that way thru this question.
SIADH cant cause pitting edema?
(i forgot the diff between pitting and nonpitting edemas, something about LDH and protein content?)
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SIADH causes gaining in poor water.. there is no change in total body Na ---> no PITTING edema !
Pitting edema occurs only with poor protein or when there is gain in total body sodium
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Old 03-20-2012
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Here how I reached to the answer B
The patient seems to have symptoms of CHF: dyspnea, fatigue, bil leg edema and weight loss (cardiac cachexia).

In CHF, the is retaining of hypotonic fluid due to increase of both ADH and Aldosterone, retaining more water than sodium.

So, both total body water and sodium increases but serum sodium conc. decrease.

And as goljan says when TB Na increase it leads to edema and this the case here.
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Hypotonic fluid retention = increase extracellular volume

Increase TB Na = edema = increase intracellular volume
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Correct Answer

I say its B

coz

the patient symptoms indicate CHF.
therefore, since low renal blood flow, and low GFR, this activates renin-angiotensin-system, which inturn activates Angiotensin-II and ALDOSTERONE.

Aldosterone, cause Na. and water retention and loss of potassium and H+ ions.

Excesses amount of ALDOSTERONE, will INCREASE the reasbosrption of Na+ and water and cause HYPERVOLEMIA.

This Hypervolemia will activate Antrial Natriuretic Peptide and cause NATRIURESIS and diuresis.

therefore hyper aldosteronism can result in a state of HYPERLOVEMIA (causing bilateral pitting edema) and Hypokalemia and metabolic alkalosis BUT with NORMAL LEVEL OF Na+.

This phenonmenon is called ALDOSTERONE ESCAPE!

Concept that i learnt from uw ...
if any 1 with a differant answer please let me know!
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Old 03-21-2012
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There is no strong hint of lung cancer: cough, hemoptysis, chest pain or other stuff (e.g. SVC obstruction blah blah) so you can exclude that.

It's B, probably due to CHF.

I do know that you can have edema with hyponatremia (but TOTAL body Na is still increased) not so sure about mechanisms.
Quote:
Originally Posted by aj23
therefore hyper aldosteronism can result in a state of HYPERLOVEMIA (causing bilateral pitting edema) and Hypokalemia and metabolic alkalosis BUT with NORMAL LEVEL OF Na+.
You mean normal or low sodium? Because the question says hyponatremia.

---
With regard to pitting/non-pitting edema: all edema is pitting EXCEPT lymphedema and myxedema in thyroid disease.

Last edited by Xaquake; 03-21-2012 at 06:00 AM.
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Quote:
Originally Posted by aj23 View Post
I say its B

coz

the patient symptoms indicate CHF.
therefore, since low renal blood flow, and low GFR, this activates renin-angiotensin-system, which inturn activates Angiotensin-II and ALDOSTERONE.

Aldosterone, cause Na. and water retention and loss of potassium and H+ ions.

Excesses amount of ALDOSTERONE, will INCREASE the reasbosrption of Na+ and water and cause HYPERVOLEMIA.

This Hypervolemia will activate Antrial Natriuretic Peptide and cause NATRIURESIS and diuresis.

therefore hyper aldosteronism can result in a state of HYPERLOVEMIA (causing bilateral pitting edema) and Hypokalemia and metabolic alkalosis BUT with NORMAL LEVEL OF Na+.

This phenonmenon is called ALDOSTERONE ESCAPE!

Concept that i learnt from uw ...
if any 1 with a differant answer please let me know!
agreed 100% true
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Old 03-21-2012
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Quote:
Originally Posted by Dr.NickRiviera View Post
NOTE: this is a USMLE Consult-"inspired" question, so look away if you plan on using USMLE Consult as a measure of your progress.


----------------------------------------------

A 60-year old woman has increasing fatigability, SOB, and ankle swelling. She also has experienced a gradual weight gain despite no change in eating habits. A physical exam shows bilateral pitting edema. Lab studies show decreased serum concentration of Na+. Which of the following is most likely?

A. Cardiac ejection is normal
B. Extracellular and intracellular fluid volumes are above normal
C. SIADH
D. Total body water is decreased
E. Venous hydrostatic pressure is decreased

(please explain your choice).
I think its B
A- the patient has symptoms of heart failure(left and right) so ejection cant be normal
C-In SIADH, the patient wud not have any signs of volume overload or dehydration(clinically euvolemic)
D.Totally body water can not be decreased as the patient as edema, must be in fluid overload. moreover, CHF(fatigue) would also cause fluid overload. PLus the patient is gaining wt despite the usual eating habits .. so it must be due to water retention
E.venous pressure wud be increased in CHF and fluid overload

i may be wrong and i hope i made sense because im not a very good explainor!
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Old 03-21-2012
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Default ya

Quote:
Originally Posted by aj23 View Post
I say its B

coz

the patient symptoms indicate CHF.
therefore, since low renal blood flow, and low GFR, this activates renin-angiotensin-system, which inturn activates Angiotensin-II and ALDOSTERONE.

Aldosterone, cause Na. and water retention and loss of potassium and H+ ions.

Excesses amount of ALDOSTERONE, will INCREASE the reasbosrption of Na+ and water and cause HYPERVOLEMIA.

This Hypervolemia will activate Antrial Natriuretic Peptide and cause NATRIURESIS and diuresis.

therefore hyper aldosteronism can result in a state of HYPERLOVEMIA (causing bilateral pitting edema) and Hypokalemia and metabolic alkalosis BUT with NORMAL LEVEL OF Na+.

This phenonmenon is called ALDOSTERONE ESCAPE!

Concept that i learnt from uw ...
if any 1 with a differant answer please let me know!
yeah that is absolutely true but i think ALDOSTERONE ESCAPE is what prevents edema in PRIMARY ALDOSTERONISM(Conn's) .. nit in secondary(due to CCF as in this case) ... due to aldosterone escape, there is NO EDEMA in primary aldosteronism.
however, secondary aldosteronism, like in the question, DOES cause pitting edema ... is what i think .. m not sure
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Old 03-21-2012
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obviously Hyponatremia

Quote:
Originally Posted by Xaquake View Post
There is no strong hint of lung cancer: cough, hemoptysis, chest pain or other stuff (e.g. SVC obstruction blah blah) so you can exclude that.

It's B, probably due to CHF.

I do know that you can have edema with hyponatremia (but TOTAL body Na is still increased) not so sure about mechanisms.You mean normal or low sodium? Because the question says hyponatremia.

---
With regard to pitting/non-pitting edema: all edema is pitting EXCEPT lymphedema and myxedema in thyroid disease.
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Old 03-21-2012
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Ans should be B.wHY?i Think this is a case of Hypo-osmotic vol expansion.it's possible she's ingesting large volume of water(possibly gthe gradual wt.gain).So therefore in Hypoosmotic volume expansion
1.ECF osmolarity decrease because of the excess volume expansion
2.ECF vol increase because of excess water intake(retension)
3.Water shift from ECF to ICF increasing the volume of ICF
4.ICF osmolarity decreases until it equals ECF osmolarity
5.Plasma protein concentration decreases becuase of the increase in ECF vol(leading to edema)
6.Hematocrit ,might expected to d3ecrrease.actually remains unchanged becuase water shift into the RBCS,increasing their vol and offsetting the diluting effect of the gains of ECF vol.
7.Because of the increase ECf vol/incr. water intake their is decrease serum {Na+}.
IT CAN'T BE SECONDARY HYPERALDOSTERONISM ?CHF/nEPROTIC Syndrome becuase in CHF/NEphrotic syndrome tehre is hyperosmotic vol expansion leading to incre ECF vol.Decrease ICF vol and incre ECF OSMOLARITYBECAUSE THEIR IS HYPONATREMIA.ALSO NOT SIADH AS NO SIGN OF CANCER.tHUS IT MAY POSSIBLY SHE IS HAVING PSYGGOGENIC POLYDIPSIA
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Quote:
Originally Posted by Joanna View Post
SIADH causes gaining in poor water.. there is no change in total body Na ---> no PITTING edema !
Pitting edema occurs only with poor protein or when there is gain in total body sodium
but it says in the stem there is decreased sodium, im still confused :/
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Old 03-21-2012
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Quote:
Originally Posted by Dr.NickRiviera View Post
but it says in the stem there is decreased sodium, im still confused :/
decreased soduim is not the same as hyponatremia ..
hyponatremia means that Na concentration in serum is low .. there may be gain in water and salt .. but in water more ... then it will cause hyponatremia right ?? but at the same time u r gaining salt so there is an increase in the Total body salt !!

Im not that good in explaining I hope you got the idea !!
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Quote:
Originally Posted by Joanna View Post
decreased soduim is not the same as hyponatremia ..
hyponatremia means that Na concentration in serum is low .. there may be gain in water and salt .. but in water more ... then it will cause hyponatremia right ?? but at the same time u r gaining salt so there is an increase in the Total body salt !!

Im not that good in explaining I hope you got the idea !!
while sodium is what me measure that goes down with SIADH, the free water that is retained is distributed across all compartments, thus excess water is in the interstitial, the vasculature, and intracellular spaces thus reducing solute concentrations in all these spaces. However overall plasma volume is regulated by sodium excretion and thus the patient remains for the most part euvolemic. Imagine for example a patient develops SIADH, his overall volume status is slightly increased by let's say 1 liter, roughly 2/3s of this is intercellular and would have no effect on edema, 1/3 is extracellular and the split the quantity and split of this 1/3 between intra and extra vascular determines the presence of edema. So therefore you would think the SIADH and the resultant free water retention might be able to cause some edema by just increasing extra vascular volume as a whole, but remember that you haven't changed the balance between intra and extra vascular volume, just the total in the intercellular compartment. Therefore the transient intravascular expansion will trigger renal salt excretion and thus volume reduction back to euvolemia albeit with reduced body wide solution concentrations.

This is not my explanation. Someone wrote it down in some other forum so I copied it in my notes. Hope it helps.
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