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Old 03-29-2013
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Question Fluid and Electrolyte Retention in Heart Failure!

Hi,
why in right heart failure, kidney reabsorbs a slightly hypotonic, sodium containing fluid? ( in goljan lecture said that gaining both water and salt, but more water than salt....but why?)
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hmm. i don't know the context of this. but my guess would be that RH failure would cause plenty of edema. so you will have increased reabsporption as compensation, and perhaps the fluid in the extravascular space wouldn't have the Na, so...ah, nvm, i don't know what i'm talking about, lol, just trying to make it up as i go along.
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Old 03-29-2013
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Quote:
Originally Posted by ethan_kien View Post
Hi,why in right heart failure,kidney reabsorbs a slightly hypotonic,sodium containing fluid? ( in goljan lecture said that gaining both water and salt,but more water than salt....but why?)
ADH secretion increases in CHF
And thats contributing to more fluid reabsorption
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Old 03-29-2013
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Here I directly quote what dr.goljan said:
" right HF and dependent pitting edema : fouid that kidney reabsorbs is hypotonic salt solution with decreased Cardiac output,means little more water than salt,therefore serum sodium will be low.
Numerator is increased for total body sodium,it the denominator has larger increase with water"

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Old 03-29-2013
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http://www.uptodate.com/contents/hyp...-heart-failure

Perfect!

Quote:
PATHOGENESIS

Like most other causes of hyponatremia, heart failure impairs the ability to excrete ingested water by increasing antidiuretic hormone levels. When cardiac output and systemic blood pressure are reduced, "hypovolemic" hormones, such as renin (with a subsequent increase in angiotensin II formation), antidiuretic hormone (ADH), and norepinephrine, respond [1-3]. Although edematous patients with heart failure have increased plasma and extracellular fluid volumes, the body perceives volume depletion (reduced effective arterial blood volume) since the low cardiac output decreases the pressure perfusing the baroreceptors in the carotid sinus and the renal afferent arteriole.

The degree of neurohumoral activation is generally related to the severity of cardiac dysfunction, as assessed by left ventricular ejection fraction or functional class [2]. The neurohumoral changes limit both sodium and water excretion in an attempt to return perfusion pressure to normal. ADH release directly enhances water reabsorption in the collecting tubules, whereas angiotensin II and norepinephrine limit distal water delivery (and thereby water excretion) by lowering the glomerular filtration rate (due to a marked reduction in renal perfusion) and by increasing proximal sodium and water reabsorption. In addition, both the low cardiac output and high angiotensin II levels are potent stimuli to thirst, leading to enhanced water intake.
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Quote:
Originally Posted by MedicalExaminer View Post
ADH secretion increases in CHF
And thats contributing to more fluid reabsorption
this makes sense! i seriously need to review my Na content vs concentration vs hypernatrEMIA, vs hypo, vs vssfd fix!

i need a break from studying. gonna finish up my pharm section, and then take a day off tomorrow.

i'm feeling very giddy, and my mind is not thinking straight.
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Old 03-29-2013
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Quote:
Originally Posted by ReggieMiller View Post
Wow...thanks...it's clear now!
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Cardiovascular-, Electrolytes-, Pathology-, Physiology-

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