What Is Hypokalemia?

Are you feeling weak, experiencing an irregular heartbeat, feeling nauseated, or vomiting? If so, there is a chance that your blood potassium is low. Medically , this is known as hypokalemia. 

Hypokalemia is a condition where potassium levels in blood serum fall below what is considered normal and healthy. It can have many causes, such as, malnutrition, disease and side-effects of medication and can be severely damaging to your health if left untreated. Fortunately, hypokalemia is diagnosed easily and can be quickly corrected depending on the underlying cause. 

On this page, you will find useful information on what causes hypokalemia, the signs and symptoms of the condition, and how it is managed and treated. 

Overview

Hypokalemia is a clinical term used when the amount of potassium in the blood is lower than normal. Potassium is an important mineral that helps our nerves and muscles work together, allows nutrients to get inside our cells and waste to leave them, and keeps our hearts healthy. The opposite of hypokalemia is hyperkalemia or an excess of potassium in the blood. 

You may develop hypokalemia for several reasons, such as, 

• Your diet doesn’t include enough potassium 
• Yourbody is getting rid of too much potassium or your cells are taking in more potassium than usual.

 Hypokalemia is often caused by medications and conditions.¹

If left untreated, hypokalemia can be fatal. Fortunately, hypokalemia is easily detected through a blood test and can be corrected by replacing the missing potassium, after which the underlying cause can be identified and addressed.  

Hypokalemia is a common mineral deficiency. About one in every five hospitalised patients experiences hypokalemia.² 

Causes of Hypokalemia

There are three main reasons for why you may experience hypokalemia:^1,3

• Your diet does not include enough potassium
• Your cells take in too much potassium
• Your body eliminates too much potassium

Your diet does not include enough potassium

If the foods you eat are not sufficiently rich in potassium, you may experience hypokalemia. 

It is important to note that diet alone rarely causes hypokalemia due to the kidney’s ability to control how much potassium is eliminated through urine. However, it can lead to hypokalemia in combination with other factors such as treatments or conditions. 

Hypokalemia that is not associated with disease or treatment can easily be corrected by consuming more potassium-rich foods or taking potassium supplements. 

Your cells take in too much potassium

The cells in your body keep a fine balance of their contents in relation to their surroundings. Levels of potassium are usually higher inside cells than outside of them. Even then, if cells take in an excessive amount of potassium, it can result in hypokalemia. 

This can either be a side-effect of medication or be caused by underlying conditions. Some of these medications include insulin, decongestants, and a type of treatment for respiratory conditions such as asthma and chronic obstructive pulmonary disease (COPD) known as beta 2 agonists. Conditions that are known to lead to hypokalemia include alkalosis and hypothermia. Hypokalemia can also be a consequence of intoxication, such as with barium or chloroquine. 

Your body eliminates too much potassium

Like cells, your body tries to maintain an adequate amount of potassium by adjusting how much of it is removed by your kidneys and digestive system. Hypokalemia is often a result of too much potassium leaving the body.

Medications like diuretics, laxatives and corticosteroids and treatments like dialysis can cause the kidneys to release too much potassium, as well as underlying conditions such as hyperreninism and aldosteronism. Conditions that affect the digestive system, such as diarrhoea, are also common causes of hypokalemia. 

Signs and symptoms of hypokalemia

You may be classified as being hypokalemic if your potassium levels in blood serum fall below a certain concentration. Depending on the severity, hypokalemia is categorised as mild, moderate or severe. In the case of mild hypokalemia, where potassium deficiency is not as severe, symptoms may not appear.¹

More severe hypokalemia can lead to muscle weakness starting in the lower limbs  and eventually reaching the  upper body. If it progresses further, hypokalemia may result in paralysis and lung failure , which can be fatal.

Other symptoms of hypokalemia may include nausea, vomiting and feelings of bloatedness.while severe hypokalemia may cause muscle cramps, rhabdomyolysis and arrhythmias. 

If you are experiencing any of these symptoms, please get in touch with your doctor. 

Management and treatment for hypokalemia

The course of action for managing and treating hypokalemia will depend on the urgency of the condition.¹ This is based on:

• The severity of the hypokalemia.
• Whether you are living with other conditions.
• How quickly your potassium levels are falling.

Here is how hypokalemia is managed depending on each situation: 

• Mild to moderate hypokalemia: replacing the missing potassium is not urgent. Hypokalemia is addressed through potassium supplements taken orally (by mouth), usually in the form of potassium chloride. If hypokalemia has already developed, diet is not sufficient to reach adequate potassium levels

• Severe hypokalemia or if symptoms are present: potassium must be replaced quickly either orally or intravenously (IV). If severe symptoms are present such as arrhythmias or cardiac ischaemia, potassium will preferably be administered through IV

• Hypokalemia resulting from losses through kidneys and digestive system: potassium must be replaced quickly to avoid complications and address the remaining deficiency in the following weeks. If your kidneys are eliminating too much potassium, a diuretic that prevents potassium from passing to urine may be administered as potassium replacement may not be sufficient in these cases

Regardless of severity, it is important to continuously keep track of serum potassium levels while you are given supplementary potassium as it may result in hyperkalemia (the opposite problem of hypokalemia, i.e. an excessive amount of potassium in the blood).  

FAQs

How is hypokalemia diagnosed

Potassium in blood serum is measured with a potassium test. You are diagnosed with hypokalemia if the concentration of potassium in your blood falls below 3.5 mmol per litre. Hypokalemia is classified as mild if your potassium in blood serum is between 3 and 3.4 mmol per litre, moderate if it is between 2.5 and 3 mmol per litre, and severe if it is under 2.5 mmol per litre. 

Following a diagnosis of hypokalemia, your doctor may then review your medications, look into your medical history for potential underlying conditions, and conduct physical exams to identify the root cause. These usually include:²

• Measuring the amount of potassium in your urine to check if the kidneys are removing too much potassium.Enquiring if you are currently experiencing digestive issues such as vomiting and diarrhoea that may be leading to excessive potassium loss
• Review any medications you may be taking, such as insulin and diuretics
• Looking for underlying cardiac conditions

If the underlying cause is not clear from any of the above, additional tests may be required to identify it, including 

• Arterial blood gas (ABG) analysis to check for metabolic alkalosis and acidosis
• A urine pH test to check for renal tubular acidosis

Identifying what is causing your hypokalemia is an important first step in addressing the underlying issue and avoiding any further issues that may negatively affect your health.

How can I prevent hypokalemia

Though it is unlikely that you may develop hypokalemia from diet alone, a healthy intake of potassium can prevent hypokalemia from occurring. Some good sources of potassium include:⁴

• vegetables like broccoli, parsnips and brussels sprouts
• Meats such as beef, chicken and turkey
• nuts and seeds
• bananas
• beans 
• Fish

It is important to note that while potassium has various health benefits, such as lowering blood pressure, excessive potassium may be harmful, especially if you are currently living with kidney disease or are taking ACE inhibitors (a type of high blood pressure medication).⁵ 

If you are living with a condition that is known to increase the risk of hypokalemia, such as diabetes, it’s important that you are aware of any changes to your health and that you have regular check-ups with your doctor to make sure you are healthy. 

If you are taking any medication that includes hypokalemia as a common side effect, make sure you check for any signs. If a medicine you are taking is behind your hypokalemia, check with your doctor if a different treatment is available. 

Who are at risk of hypokalemia

Some groups have been identified as having a greater risk of developing hypokalemia. You may have a higher risk if you:^1,6

• Have been diagnosed with kidney failure, cardiovascular disease (such as hypertension), shock, malnutrition, hypothermia, or diseases that increase the number of blood cells in your body, such as leukaemia.
• Live with a psychiatric condition and take medication for it.
• Are hospitalised, especially if you are a child or teenager, are experiencing fever and are critically ill.
• Are taking more than one medication due to multiple conditions, usually as a result of old age (age alone doesn’t seem to increase risk).

Consult your doctor if you think you might be at risk. 

How common is hypokalemia

Hypokalemia is among the most common electrolyte deficiencies, but severe hypokalemia is uncommon.^1,2,6 More than one in ten patients that do not stay overnight are tested with mild hypokalemia, which usually doesn’t cause symptoms. Around one in five patients staying overnight experience hypokalemia, with only around one in twenty cases being of clinical concern. 

Hypokalemia is more common in patients taking certain medications with about four of every five people taking diuretics developing hypokalemia. 

No differences have been found in how frequently people that have been assigned male at birth (AMAB) or female at birth (AFAB) experience hypokalemia.  

When should I see a doctor

If you are feeling any symptoms associated with hypokalemia, such as muscle weakness or cramps, irregular heartbeat, difficulty breathing, vomiting or nausea, please get in touch with your doctor. 

Summary

Hypokalemia is a condition that can have many causes, including a poor diet, medication, underlying conditions, or a combination of these.

If left untreated, hypokalemia can severely impact your health and even be life-threatening. To prevent this, it is important that you are aware of the signs of hypokalemia and, if you are taking medication or live with a condition that can increase the risk, attend any check-ups scheduled by your doctor.

Hypokalemia is manageable if caught in time by replenishing missing potassium and addressing any potential causes behind it such as underlying conditions and medications.