3 Tricks to Help You Remember Electrolyte Imbalances

You really need to memorize the normal lab values for each of the six common electrolyte imbalances (sodium, potassium, calcium, chloride, magnesium, and phosphate).  By the way, did you think I never like memorization?  I actually do, but only for very particular types of information, like lab values.  However, once you’ve memorized the lab values, you really need to focus on understanding the underlying workings of the Big Three:  sodium, potassium, and calcium.

This can be trickier than you think, however, as there are many general, nonspecific sounding symptoms (dry mouth?  dizziness?  irritability?) that can make it difficult to tell them apart.  On top of that, there’s quite a bit of symptom overlap between the different imbalances.  In other words, some imbalances actually have similar or the same symptoms!  Put those challenges together, and you end up with a very confusing topic to study.  Fortunately, it’s not really too confusing once you understand how to organize the nursing information so that you can remember it more easily.


There are lots of different ways to organize the information you need to know about electrolyte imbalances, but one easy way that I like to use is simple opposites.  For example, if you learn that muscle tetany (aka clenched muscles) occur in hypocalcemia, then you should see muscle weakness or flaccidity in hypercalcemia.  And, in fact, those are two major symptoms that are tested on for calcium imbalance.


Another way to help organize the information so that it is easier to understand and remember is to look for similarities between the symptoms of an imbalance and a completely different illness or disorder.  For example, hyponatremia (low sodium) has a lot of overlapping symptoms with dehydration.  Since water follows sodium (remember that from studying fluid imbalances?), then it makes sense that if there are low levels of sodium in the body then there will probably also be lower levels of water.  Most people can easily remember the symptoms of dehydration, so now you can more easily remember the symptoms of hyponatremia, too!


A third way to help you organize your new nursing knowledge is to look for patterns that occur when certain electrolyte imbalances have a tendency to be comorbid (aka occur at the same time).  For example, we already established that a symptom of hypocalcemia is tetany.  Well, a symptom of hypomagnesemia causes CNS hyper irritability, which is usually assessed by abnormally strong reflexes (anything higher than a 2+).  Another way of looking at it is to consider strong reflexes as a type of muscle rigidity, or tetany.  And in fact, calcium and magnesium imbalances tend to occur together.  That is, if you have hypocalcemia then you’re more likely to also have hypomagnesemia.  And so many of their symptoms overlap and can be memorized together.

What tips or tricks have you found to help you remember the symptoms of electrolyte imbalances?  

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  1. Valentina

    I was just reading the subtypes of hypo/hyper-natremia and it was confusing to me. I found the discussion part very helpful. Thank you. Please add me to your mailing list.

  2. justin

    Good article, but one constructive comment:

    Hypernatremia, not hyponatremia, has s/s that mirror deydration such as thirst, dry membranes, high body temp.

    Hyponatremia, low sodium, is typical of excess fluid volume. Your sodium is low because your extracellular fluid volume is high, causing the sodium to be diluted.

    So what you wrote under “similarities” is the opposite in reality.

    • Hi Justin,
      Thanks for your comment! That’s a good point, and it brings up a good discussion.

      There’s actually two causes of hyponatremia: 1) fluid volume excess (aka too much water in blood vessels, but sodium does NOT proportionately decrease), and 2) both water AND sodium in the blood vessels decreases. The second type of hyponatremia is actually more common, as it can be caused by GI issues (excessive vomiting/diarrhea) among other things. The type of hyponatremia caused by fluid volume excess is less common because the situations that cause it are also less common (i.e. too much IV hypotonic fluid, SIADH, etc).

      That being said there are slightly different symptoms depending on which sub-type of hyponatremia it is. When there’s a decrease in BOTH water and sodium, then you can definitely see symptoms similar to dehydration, such as dry mucus membranes and thirst.

      You see a similar story with HYPERnatremia: it can be caused by 1) increased sodium, or 2) decreased water. And in fact, the “decreased water” cause what we consider TRUE dehydration. So hypernatremia would also have some overlapping symptoms.

      In any case, I think we’re BOTH correct! And I think it perfectly illustrates why I think it’s so important for nursing students to focus so much study time on fluids and electrolytes, so they can understand the concepts and be able to have a discussion like this one. It definitely helps to better understand the symptoms and keep them straight for the long-term!

    • Althea

      But having excess fluid volume doesn’t say you are hydrated. As in third spacing or fluid shift. So technically, you’re still dehydrated.

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