Disorders of Potassium Homeostasis

[MudPhud20XX]

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One of the Kaplan physio questions:

Which of the following conditions will cause increased plasma potassium with decreased urinary potassium excretion?
A. acute acidosis
B. acute alkalosis
C. chronic acidosis
D. chronic alkalosis

I chose A and the answer is A too.

But why not C, chronic acidosis? The solutions just says that the effect of chronic acidosis on urinary potassium is different and doesn't go into detail. Can anyone help me out?
Many thanks in advance.

 

[Handinhand]

Going off of the last question you just asked about potassium shift in an acidosis we can build off of this. We know why we have an "increase" in potassium, although this isn't actual an increase as we haven't actually taken on more potassium, it's just a shift into the plasma which we measure.

Now, whether we have a respiratory or metabolic acidosis, we would expect that if there was a chronic mechanism for this that we would have some kind of compensatory mechanism to bring the blood pH close to normal again. The acute hyperkalemia is a by product of cellular buffering, but that's not effective long term and once the acidosis can be better dealt with by the kidneys and lungs, your potassium should return to normal(ish).

 

[Nephronlearner]

Diggidy wrote a good explanation.
Kidneys have the additional ability to compensate for the chronic change by increasing/decreasing excrection of bicarbonate (which takes time).