virgola82
Forum Guru
Topics: 85
Posts: 348
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Hi everyone,
I don't know why but I can't really figure out the exact mechanism of hypotonic gain of fluid in the kidney of right heart failure or cirrhosis patients leading to hyponatremia. Can someone be so kind to explain that to me? I mean why there is hypotonic gain of fluid in right heart faliure?
Thanks in advance
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| virgola82
Forum Guru
Topics: 85
Posts: 348
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I think this is the mech:
In CHF, as in cirrhosis, there is lower GFR and thus lower cortico-medullary osmolar gradient (less Na filtered available ?). If the coritico medullary gradient is lower it is more difficult to pump Na through the Na/K/2Cl transporter in the thic ascending limb and thus less free water is formed in the tubule. If less free water is generated it means that the urine is not going to be diluted.
In summary less interstial osmolarity -> less free water -> no dilution (ie urine osmolality never below 300) -> hypotonic gain of fluid (that fluid that should have been intratubular free water) -> hyponatremia (if he drinks enough)
please if this is wrong let me know
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