DrVirgo
Forum Hero
Topics: 1096
Posts: 3,515
|
For Euvolemic Hyponatremia in Kap, the two examples which are listed are:
-SIADH and
-Psychogenic Polydipsia
IN BOTH these examples insn't the volume (ECF) INCREASED????
As I remember from Step 1 (Goljan)
Serum Na = TBNa/TBW
In both SIADH and Psychogenic Polydipsia:
-NO change in TBNa
-Increase in TBW
-Therefore Serum Na Decreases (HYPONatremia)
-BUT ECF should INCREASE, because there is a GAIN of FLUID.
(Remember those rectangle looking diagrams from Kap Physio with the ECF, ICF, and Osm)???
___________________
Our greatest glory is not in never falling, but in rising every time we fall.
|
| dr.wad
Forum Senior
Topics: 3
Posts: 350
|
as i remember the explanations is >> the added volume of water will lead to increase in the GFR which will increase the excretion of the added water accompanied by Na>>
so the ECF will remain normal or slightly increased but the Na loss will continue.
|
| cirus
Forum Guru
Topics: 108
Posts: 740
|
In SIADH, if pt is symptomatic d t hyponatremia, then u have to supply him with Na, to rembuce the defecit (usually start with hypertonic Saline or accord to present), if not, just a lab finding, i.e. the pt is asymptomatic then the first choice would be Fluid restriction (800-1000ml/d), if not responding & still low Na, then demeclocycline is a good alternative
in psychogenic polydipsia, the pt will complain of poluria & polydipsia, + both Urine & serum will have low osmolarity d t dilution. / while in SIADH the urine osmolarity will be high (>110) as a reult of inappropriate naturises while the serum will be low (<280mOsm/L)
|
| DrVirgo
Forum Hero
Topics: 1096
Posts: 3,515
|
dr.wad wrote:
as i remember the explanations is >> the added volume of water will lead to increase in the GFR which will increase the excretion of the added water accompanied by Na>>
so the ECF will remain normal or slightly increased but the Na loss will continue.
Same explanation for SIADH AND Polydipsia? Is this a correction or compensation, and how long does it take to normalize ECF?
Thanks.
___________________
Our greatest glory is not in never falling, but in rising every time we fall.
|
| DrVirgo
Forum Hero
Topics: 1096
Posts: 3,515
|
cirus wrote:
In SIADH, if pt is symptomatic d t hyponatremia, then u have to supply him with Na, to rembuce the defecit (usually start with hypertonic Saline or accord to present), if not, just a lab finding, i.e. the pt is asymptomatic then the first choice would be Fluid restriction (800-1000ml/d), if not responding & still low Na, then demeclocycline is a good alternative
in psychogenic polydipsia, the pt will complain of poluria & polydipsia, + both Urine & serum will have low osmolarity d t dilution. / while in SIADH the urine osmolarity will be high (>110) as a reult of inappropriate naturises while the serum will be low (<280mOsm/L)
Thanks for the explanation... I know about osmolarity, what what about VOLUME or ECF? What happens to it and why?
___________________
Our greatest glory is not in never falling, but in rising every time we fall.
|
| DrVirgo
Forum Hero
Topics: 1096
Posts: 3,515
|
I'm still wondering about this... Since Kaplan says SIADH and Psychogenic Polydipsia have a normal ECF (I always thought it should be increased).
Ok, so am i right with the following explanation:
In both SIADH and psychogenic polydipsia
1. HYPOnatremia and Increased ECF at first because of fluid gain
2. Body increases GFR --> Loss of H2O and Na --> ECF normalization
Is this the mechanism by which we get a NORMAL ECF???
Please confirm.. anyone!
Thanks.
___________________
Our greatest glory is not in never falling, but in rising every time we fall.
|
| RitaM
Forum Newbie
Topics: 1
Posts: 61
|
In Siadh Body does not excrete water.We have to water restrict to one litre a day to bring back the serum na to N.Also Demeclocycline is a good alternative .The rise in Na should not be more than 5 a day.
|
| genbot
Forum Guru
Topics: 14
Posts: 627
|
You see when you say euvolumic hyponatremia u dont need to calcute the patients volume status to reach that conclusion.
The EUVOLUMIC statement is based on the fact that these patients have no CLINICAL EVIDENCE of volume overload, i.e they have no EDEMA, jugular venous distension or pulmonary congestion
___________________
Step1 267/99. Step2 269/99. CS pass. ECFMG certified. Match 2009. MAY THE FORCE BE WITH ME (The one they call the strong nuclear force!)
|
| DrVirgo
Forum Hero
Topics: 1096
Posts: 3,515
|
genbot wrote:
You see when you say euvolumic hyponatremia u dont need to calcute the patients volume status to reach that conclusion.
The EUVOLUMIC statement is based on the fact that these patients have no CLINICAL EVIDENCE of volume overload, i.e they have no EDEMA, jugular venous distension or pulmonary congestion
thanks, that makes sense, but what is the mechanism of EUvolemia in SIADH and psychogenic polydipsia, because logically thinking Increased ADH increases water in the interstitial space. And increase intake of crazy amounts of water in psychogenic polydipsia does the same. So HOW is the patient still EUvolemic? -Is my explanation about GFR correct -from my previous post?
Thanks again.
___________________
Our greatest glory is not in never falling, but in rising every time we fall.
|
|
| |
| | | | | | | | | |
