Metabolic Alkalosis: Causes, Symptoms, and Treatment

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  • 0:01 When an Ion Goes Missing
  • 1:13 Why Does Metabolic…
  • 5:28 Compensation, Tests, &…
  • 8:03 Lesson Summary
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Lesson Transcript
Instructor: Artem Cheprasov

Artem has a doctor of veterinary medicine degree.

We'll learn what metabolic alkalosis is all about in this lesson and how the respiratory system tries to save you from this potentially life-threatening condition.

When an Ion Goes Missing

Fans of documentary crime shows are well aware that sometimes people go missing because they are taken away, get lost, or because they just want to go missing on their own and leave their old lives behind. In a quirky way, this has to do with acidic ions in your body that also go missing as a result of disease states. And just like people and families suffer as a result of a missing loved one, your body suffers as a consequence of this missing ion.

Metabolic alkalosis is a condition that occurs as a result of decreased hydrogen ion concentration or increased bicarbonate ion concentration not as a result of primary respiratory issues. The hydrogen ion is acidic and the bicarbonate ion is basic. If too much acid is lost or too much of a base is gained, then our body becomes alkaline due to an absolute or relative base excess. As a result, alkalemia ensues. Alkalemia is an abnormally high pH of the blood, > 7.45.

Why Does Metabolic Alkalosis Occur?

Let's examine the reasons as to why this pathological state can occur. Our first possibility in a criminal investigation of a missing person's case is that someone went missing or got lost as a result of a criminal act or by accident, such as when people leave their home and get lost in the woods. It doesn't really matter which one occurs because the person is unfortunately gone.

Well, anything that causes the loss of hydrogen out of the body can cause metabolic alkalosis. One possibility is the loss of hydrogen through kidney excretion. A condition called hyperaldosteronism causes the excess secretion of hydrogen (and potassium) out of the body by way of the kidneys.

Another way by which hydrogen can be lost from the body is through vomiting. Your stomach is full of acid. By vomiting a lot or for a long period of time, we deplete our body's stores of acid, and this leads to a rise in the pH of our body (alkalosis), which subsequently causes the pH of our blood to increase (alkalemia). In either case, the acid is lost in excess, and relative to this loss, the amount of bicarbonate has increased in the body. Bicarbonate is basic and hence we're stuck with alkalosis.

While people may get lost or kidnapped, sometimes they just disappear and hide on their own. Maybe they're hiding from the IRS somewhere abroad or from a criminal gang while in the witness protection program. The end result is that they're still there. They're alive; they're just hidden from view.

Our acidic hydrogen ions also employ this strategy in certain instances, with the end result of alkalosis. Here's one reason how. Sometimes our body loses too much potassium. This can occur as a result of the hyperaldosteronism I just discussed or by the administration of specific diuretics (also known as water pills), among other causes. If potassium is lost in excess from the body and blood, which we term hypokalemia, then the body must do something about this. Just as Newton's third law of motion implies an action must have a reaction, the same deal goes for our biological systems that always react to a certain event.

From your basic cellular biology classes you should've learned that potassium is the main intracellular (within cells) ion. It, like hydrogen, carries a positive charge. If potassium is lost from the body, it is also lost from within our cells. Since the cells lose positively charged potassium ions, they become more negative.

Cells don't like this; they want to maintain an electrochemical balance. Therefore, cells react by telling the positively charged hydrogen ions to leave the blood and enter inside to restore the appropriate electrical charge. This means the hydrogen ions essentially hide away inside of our cells. This, as before, causes alkalemia (a high blood pH).

Okay, lastly I want to discuss the final overarching cause of alkalosis. This is when too much bicarbonate (our base) is added to our system. This happens when bicarbonate is administered, paradoxically, to treat acidosis. The exact details of why this occurs are beyond the scope of this lesson, but you can think of it as a couple (the hydrogen ions) walking down the street, only to be surrounded by a mob (bicarbonate that's injected into a person) out of nowhere. There's not much the two people can do; they're overwhelmed and alkalosis results.

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