drake19

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Jul 26, 2010
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I just wanted to clarify acid-base status w/ diarrhea

I had a question on my medicine shelf that asked which electrolyte would increase in the serum w/ diarrhea.

Would you get a normal anion-gap metabolic acidosis (low HCO3, hypokalemia, increase Cl). Are those the 3 main electrolytes affected?
 

Wolverines83

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Sep 29, 2010
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pooping out the bicarb makes you reabsorb cl to stay electrically neutral. So your anion gap is normal because the increase in chloride is "compensating" for the decrease in bicarb (in the formula).

usually physically losing bicarb (diarrhea) leads to normal anion gap
using up bicarb (lactic acid) leads to increased gap
 
Aug 9, 2014
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Also potassium is present in such minute amounts in ECF that it doesn't typically push the gap one way or the other. Hence the typical equation Na - (Cl + bicarb).