Sodium/Potassium Relationship

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Fluids and electrolytes have never been my strong point. Especially electrolytes! Like many so many other students posting here I get confused between hyper/hypo and all the S/Sx. I purchased 'Fluids & Electrolytes Made Incredibly Easy' which is helping some but I'm still lost on some things. I think I'm guilty of not looking at the "big picture".

Today what I can't figure out is why sodium and potassium have an inverse relationship. Last semester in clinical I had a patient who had low sodium and high potassium. I'm still stumped as to why. I probably wouldn't have connected the 2 at all if my professor hadn't called it "interesting" on my care plan. BUN, Creat, and GFR were all normal; the patient was in for something completely unrelated to fluids (kyphoplasty).

Sorry I'm kind of long-winded. Anyway I know there's something I'm missing. The only thing I can think of is something to do with the Sodium Potassium pump? Could someone tell me if I'm even close to being correct or point me toward another electrolytes for dummies resource? :)

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Hello,

I believe your right, it has to do with the K+/Na+ pump.

For every 2 K+ being put into to the cell, 3 Na+ are pumped out - somewhat of an inverse relationship.

I'd look at the Khan Academy vids on the subject for clarification - post what you find

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Hmm, well the Khan Academy vid on the Sodium Potassium pump does explain how it works but doesn't give any leads on abnormals.

In this video -

- at approx. 18:15 it talks about glucose lowering sodium. The patient's glucose was a little high, 109. Would that be enough to do it? And if so then what caused the high Potassium; not enough sodium for the pump to work?
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A down and dirty simple explanation::: during periods of hemostasis there are more K+ ions than Na+ ion in the ICF and more Na+ ions than K+ ions in ECF, however the osmolarity of both compartments are equal...

With the loss of Na+ ions the osmolarity changes and H20 will cross to again equalize. Thus now you have more H2O in the ICF {the cells swell}.

Blood tests measure the concentration of electrolytes as well as only measuring plasma amounts not amounts contained within each cell...

With more H2O being in the ICF you have effectively concentrated the amount of electrolytes being tested and their numbers will appear higher without there actually being an overload... When the Na+ is stabilized and the H2O shifts back the values will return to normal.

This is assuming that everything else for this patient has been evaluated and treated.. as there are also many medications and other conditions that could explain the lab values.

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Specializes in Informatics / Trauma / Hospice / Immunology.

Kidney failure is a significant cause of uremia, which is the buildup of metabolic waste products including potassium. However, your creatinine and BUN are fine.

Next consider possible organ, tissue, and even vascular damage. When cells rupture, such as the collapse of a tumor, or the injection of too much sterile water (bad flushing practice used somewhere), potassium is released from within the cell (where it mostly resides) and builds up in the blood.

Diet is another consideration in terms of temporary spikes in potassium. Likewise medications.

In addition to the sodium-potassium pump, review the role of sodium and potassium in the action potential of muscle, the pancreas, and nerves. It is the uncontrolled rise in potassium that leads to cardiac arrest through failure of cardiac muscle to generate effective action potentials.

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Specializes in Critical Care, ED, Cath lab, CTPAC,Trauma.

Check out this thread in our FAQ section of students....let me know what you think!

Really need help with electrolytes and fluids

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Specializes in Critical Care, ED, Cath lab, CTPAC,Trauma.
Fluids and electrolytes have never been my strong point. Especially electrolytes! Like many so many other students posting here I get confused between hyper/hypo and all the S/Sx. I purchased 'Fluids & Electrolytes Made Incredibly Easy' which is helping some but I'm still lost on some things. I think I'm guilty of not looking at the "big picture".

Today what I can't figure out is why sodium and potassium have an inverse relationship. Last semester in clinical I had a patient who had low sodium and high potassium. I'm still stumped as to why. I probably wouldn't have connected the 2 at all if my professor hadn't called it "interesting" on my care plan. BUN, Creat, and GFR were all normal; the patient was in for something completely unrelated to fluids (kyphoplasty).

Sorry I'm kind of long-winded. Anyway I know there's something I'm missing. The only thing I can think of is something to do with the Sodium Potassium pump? Could someone tell me if I'm even close to being correct or point me toward another electrolytes for dummies resource? :)

Without a complete picture of the patient it is impossible for me to help you know why the lytes were off. what other co morbidities were present. How did the compression fracture occer and how old was it? What oither meds were they on? How low is lw NA? How high is the elevated K?
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Specializes in Adult Internal Medicine.

Tell us what meds the patient was on ;)

Sent from my iPhone.

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The patient had dementia but according to his wife the compression fractures - 1 at T12, 1 at L4 - were old work (construction) related injuries. I don't know how old unfortunately; if she told me I didn't write it down, but the patient was 92 so I'd guess at least 20 years if not older.

Potassium was 5.2, sodium was 131.

Meds were: Amicar (aminocaproic acid), Aricept (donepezil), Atrovent (Ipratropium), Colace (ducusate), Ipratr-Albuterol, Lopressor (metoprolol), Megace (megestol), Namenda (memantine), Zestril (lisinopril), Zocor (simvastatin). He had Ducolax (bisacodyl), milk of magnesia, and Norco 10/325 PRN but didn't take any of those while I was there.

His last bowel movement was a week prior so no diarrhea despite all those laxatives.

Esme, I had actually viewed that thread in my search and really liked it! The replies you and GrnTea made helped me understand more about electrolytes and fluid balance than my whole AP class! But I don't think any of the symptoms applied to this patient, unless the answer is staring me in the face and I'm missing it :down:

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Specializes in Adult Internal Medicine.

Why was he on amicar? Was he pre or post op? How long?

He was having kypho for an old compression fx?

Several of those meds are common culprits in hyperkalemia ;)

Sent from my iPhone.

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Specializes in Critical Care, ED, Cath lab, CTPAC,Trauma.

The meds explain plenty....I agree with Boston...why was he on Amicar?

Changes in electrolytes is not always "fluid" (excess/dehydration) related. Sometimes, cells release too much potassium. Releasing too much potassium can result from:

  • Breakdown of red blood cells, called hemolysis
  • Breakdown of muscle tissue, called rhabdomyolysis
  • Burns, trauma, or other tissue injury

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Ok so I'm an idiot who probably should've looked at the care plan more carefully before posting. It turns out he somehow got a huge skin tear being moved in the OR! The hospital (understandably) didn't want a student to get anywhere near it which I think is why I forgot about it. That's why he was on the Aricept.

So just to make it absolutely clear to my ditzy brain; the potassium went up from the meds/tissue trauma, and the sodium fall was from something else, like laxatives?

Sorry everybody, I feel like a real space case here, but I'm just trying to clarify any connection between the two! Thanks for being so patient!

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