Hypokalemia occurs when the body excretes too much potassium. People with the condition do not have enough of this crucial mineral in the blood. Severe hypokalemia can lead to signs and symptoms such as muscle weakness and other health problems.

Hypokalemia is a type of electrolyte imbalance that results from very low potassium levels in the blood.

Potassium is an essential mineral that helps regulate different organs and processes in the human body. Potassium deficiency can impair the function of the kidneys, muscles, heart, and nervous system.

Hypokalemia usually occurs as a symptom of another condition or as a side effect of medications that increase the flow of urine.

The opposite of hypokalemia is hyperkalemia, which is when potassium levels are too high. According to a 2017 study, about 1 in 11 people typically arrive in the emergency room due to symptoms of too high or too low potassium levels.

In this article, we look at the symptoms, causes, diagnosis, and treatment of hypokalemia. We also discuss the outlook for people with low potassium levels.

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Symptoms of hypokalemia can range from mild to severe. People with mild symptoms may not recognize they have the condition.

Some people may also not have any symptoms at all. However, when they do, they may experience:

Since the condition can also impair the function of the kidneys, people with hypokalemia can urinate too much while feeling extremely thirsty. Cognitive impairment may also occur.

Moreover, during physical activity, when the engaged muscles are releasing potassium, hypokalemia can lead to insufficient blood flow to the muscle, causing pain and ultimately resulting in the destruction of the skeletal muscle. The condition can also paralyze the bowel.

Hypokalemia can become life threatening if it affects the heart muscle, causes paralysis, or impairs the functioning of the lungs.

However, a 2014 study suggests that severe hypokalemia is rare. Of 4,826 people who presented to the emergency department with hypokalemia, only 1% had a severe condition. Additionally, only half of the people in this subgroup had any symptoms.

Potassium plays an important role in many bodily functions, including the contraction of muscles, the functioning of enzymes, and the flow of fluids between cells.

The kidneys regulate potassium concentration in the body by regulating the passing of urine. Hypokalemia occurs when this process stops working, and the body loses too much potassium through urine or sweat.

In rare cases, hypokalemia can occur, because a person is not getting enough potassium from food. However, it is unusual for this to be the cause, as many foods contain potassium, such as bananas, avocados, chard, and other plant-based foods.

The kidneys are usually able to reduce the excretion of potassium if the body is not getting enough of the mineral.

However, a person can lose potassium too quickly for several reasons, including:

  • persistent diarrhea
  • prolonged vomiting
  • kidney issues
  • a side effect of drugs that promote urination

Hypokalemia can also develop when potassium does not transmit correctly between cells. This can be a side effect of taking various medications.

To determine whether a loss of potassium indicates hypokalemia, a doctor will need to identify the cause of the loss. In most cases, this is relatively straightforward.

A doctor will check for:

  • recent vomiting
  • recent diarrhea
  • associated heart problems
  • specific medications, such as insulin, medications that help open the airway, or those that increase urine production

If a doctor suspects that a person has hypokalemia, they may run tests to measure the amount of potassium in their body. They will usually do this by checking the potassium level in a person’s urine over 24 hours. They can also order a blood test.

A chemical imbalance in the body showing too much or too little acid can also be an indicator of the condition.

Normal potassium concentration in the body ranges between 3.6 and 5.0 millimoles (mmol) per liter. The kidneys excrete at least 5 mmol, or 195 milligrams (mg), of potassium daily, which means that a person needs to consume 400–800 mg of this mineral per day.

Hypokalemia can also cause an abnormal or irregular heartbeat, especially in older adults, people with heart disease, or those taking heart-regulating medications.

People with the condition may need an electrocardiogram to monitor their heart.

Once a doctor has determined the underlying cause of a person’s hypokalemia, they can recommend the right course of treatment and the correct way to replace the potassium.

Doctors may instruct people to eat foods rich in potassium. However, authors of a 2015 article note that while changing the diet can be beneficial, it is usually far less effective than taking potassium supplements.

In severe cases, a doctor will administer potassium intravenously.

The outlook for a person with hypokalemia will depend on what causes it. In some cases, this may be simple to resolve. In others, the cause may be more complex.

Hypokalemia can be a symptom of several conditions, including:

Additionally, hypokalemia can be a side effect of certain antibiotics, corticosteroids or laxatives, or drugs that promote urination.

Hypokalemia is when there is not enough potassium in the body. It usually occurs together with a condition that causes a person to excrete too much potassium.

More rarely, however, hypokalemia develops when a person does not consume enough of the mineral.

The general treatment is to replenish the potassium in the body and to treat the underlying cause.