Potassium and Its Profound Impact on Your Health

Why low potassium could be dangerous, and how to treat it safely

From the time it was first isolated from the ashes of plants (potash) thousands of years ago, our understanding of the chemical element potassium has increased. Today, it would not be an overstatement to say that life, as we know it, would not be possible without potassium. We are referring not just to the functioning of the human body here. Potassium, in fact, is necessary for normal function of virtually all living organisms.

Products rich of potassium and magnesium

Potassium's Central Role in our Physiology

The bulk of our body's potassium is found inside cells, and not outside in the fluid that bathes those cells (called extracellular fluid). This big differential in concentrations is maintained by an enzyme that is fundamental in maintaining the integrity of all animal cells, and it is called the sodium-potassium ATPase pump. This is located on the membrane that envelops a cell.

This enzyme pumps sodium out, and potassium in to the cell, in a 3 to 2 ratio. This ratio between the potassium concentration inside a cell and outside of a cell is the driving force in generating its electricity, called the action potential, without which muscle and nerve cells cannot execute their functions. The next time you drink your favorite electrolyte beverage with potassium, do take a moment to realize the profound ways it controls your physiology.

The Kidney's Role in Regulating Potassium Levels

Like with most electrolytes, the kidney has the major responsibility of maintaining the normal blood level of potassium. Therefore, both low and high potassium levels are possible in disorders of the kidney. There are other mechanisms which impact potassium level in our blood as well (like the oral intake of potassium as part of food, acidity of our blood, etc.), but on a minute-to-minute basis however, the kidney is the main regulator. If potassium concentration is the blood gets too high, the kidneys start to excrete the excess out into the urine. Should the level fall too low for comfort, the kidneys can reduce excretion to a bare minimum. Inability of the kidneys to respond in this normal manner even in the face of low blood levels of potassium is called renal potassium wasting.

Abnormally Low Potassium Levels in the Blood: Hypokalemia

Renal potassium wasting is just one reason for abnormally low levels of potassium in the blood. From a conceptual standpoint, an easy way to understand reasons for low blood potassium is to divide those causes into two categories: situations of either low supply of potassium in to the blood, or situations of increased loss. However, here is a more complete list:

  • Decreased oral intake of potassium containing foods
  • Increase loss of potassium from the gut—these could include entities like diarrhea where potassium is lost in stools, or vomiting, where significant vomiting can lead to increased loss of potassium in the urine (due to mechanisms beyond the scope of this article).
  • Increase loss of potassium in the urine—this phenomenon can be seen due to elevated level of mineralocorticoids (hormones produced by adrenal gland that act on the kidney to regulate potassium secretion), and due to external reasons (like use of diuretics, also known as "water pills", eg. furosemide or hydrochlorothiazide. Other causes include rarer entities like Bartter syndrome, Gitelman syndrome, drugs like amphotericin B, etc.
  • Increased entry of potassium into cells, so that the level will not be measured on routine blood testing (which tests potassium level in the serum, which is the liquid plasma the bathes our cells, minus certain proteins). In these situations, the total amount of potassium in the body is essentially the same and there is no net deficit. However, since it's location changes, it cannot be measured. This can result from elevated levels of insulin, high alkalinity in blood, etc.
  • Increase loss of potassium from excessive sweating. This is especially seen in patients with cystic fibrosis.

How Does Low Potassium Impact Your Health?

Alterations in our muscle and nerve cells' electricity, or the action potential, is the main reason behind the symptoms and signs that you could experience due to low potassium levels. Here is a short list of what problems you might experience:

Safe Treatment of Low Potassium Levels Is Critical 

Cautious supplementation and repletion of potassium can treat hypokalemia and bring the levels up to normal. However, the underlying cause of hypokalemia needs to be identified as well so that the disease, and not just its sign/symptom is being treated. In patients who have significant wasting of potassium from the kidney, certain kind of medications, referred to as potassium sparing diuretics might be of immense help.

Extreme caution should be exercised with intravenous supplementation of potassium since infusions can be painful if done the wrong way, or too fast. The bigger danger however in these situations is too much or too rapid potassium supplementation, which will lead to dangerously high potassium levels in the blood. As you might have gathered by now, our body functions normally within a certain range of blood potassium. Anything higher or lower than that could become life threatening in severe cases. Needless to say, treating severe hypokalemia is not a DIY project and should be done under the supervision of a physician, even if you plan to do it at home. If the cause of low blood potassium is not obvious, or if treatment requires an inordinate amount of potassium repletion, highly consider getting a consultation with a specialist physician who treats these issues, that is, a nephrologist.

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