What Are the Potassium Levels

Generally, normal potassium levels fall within a range from 3.5 to 5 mmol/l. Values above 5 mmol/l indicate hyperkalemia, while below 3.5 mmol/l indicate hypokalemia.

Hyperkalemia, or hyperpotassemia, refers to high potassium levels in the blood.

“Hyperkalemia can be classified into three types depending on the value:

• From 5.5 to 5.9 mmol/l: mild;
• From 6.0 to 6.4 mmol/l: moderate;
• Above 6.5 mmol/l: severe. If blood potassium levels exceed 6.5 mmol/l, the situation is critical and can endanger the patient’s life, so it's essential to act quickly with specific tests and therapies,” explains Dr. Furlan.

“In general, potassium levels rarely rise due to excess food intake but are mostly related to reduced potassium excretion by the kidneys or because potassium, which was once inside the cells, leaks out. If the amount of potassium that leaks out is high, it causes the so-called hyperkalemia.

Other causes of high potassium in the blood can include:

• Kidney diseases;
• Endocrine diseases (e.g., adrenal disorders);
• Rhabdomyolysis, which is muscle damage caused by falls or trauma, leading to the rupture of muscle cells and the release of potassium;
• Major burns or large tissue hemorrhages, where potassium leaks from cells into the blood. One of the most frequent causes is the intake of potassium through medications: there are potassium-based drugs or drugs that block potassium elimination, causing it to increase.

The first thing to do when a patient presents with high potassium levels is to check the medications they are taking. A thorough medical history should be taken to determine possible causes (e.g., whether the kidneys are functioning properly, whether there have been trauma or burns, or, less commonly, adrenal insufficiency) and to set up the most appropriate treatment,” continues Dr. Furlan.

High potassium manifests in an abnormal way. Essentially, it is asymptomatic unless it reaches levels that can harm the person.

“One of the most typical (and dangerous) manifestations of high potassium is malignant arrhythmias, because the main function of potassium inside the cell is to control muscle contraction, not only in the body but also in the heart.

Many times, in the Emergency Department, we notice that a person has high potassium just through the electrocardiogram because there are certain characteristics (e.g., an excessive rise in the T waves) that suggest this condition.

We then proceed with blood tests, and if high potassium levels are found, we prescribe therapy. At that point, it is important to know whether the patient is taking medications to suspend them,” continues the specialist.

At this stage, hydration is crucial. There are two ways to expel excess potassium:

1. Eliminate it through urine with diuretics;
2. Bring it back into the cells with insulin: administering a “repolarizing drip,” consisting of a glucose solution and insulin, helps potassium return to the cells.

The most important step for a patient with severe hyperkalemia is to immediately perform an electrocardiogram and start therapy right away. Afterward, the cause is investigated, but first, the patient must be stabilized.

In hypokalemia, the opposite occurs: in this case, potassium concentration is below 3.5 mmol/l. The causes are usually linked to excessive potassium loss, such as:

• Kidney malfunction;
• Medications like laxatives and diuretics;
• Excessive sweating.

Certain endocrine diseases can also cause low potassium, such as some adrenal gland disorders or conditions like excessive vomiting, anorexia, or malabsorption.

It can manifest as extreme muscle weakness and, in severe cases, even arrhythmias.

Treatment involves administering potassium through drips at low doses to restore normal levels. These treatments can also be done at home with specific potassium and magnesium preparations.

There is also another rare condition, but one we have seen in the Emergency Department, called familial hypokalemic periodic paralysis, which is a full-body paralysis caused by low potassium damaging the muscles. Correcting potassium levels will resolve the issue.

“In addition to the therapies already described, dietary interventions can also help. There are many foods rich in potassium, such as:

• Bananas;
• Green vegetables (spinach, fennel, Brussels sprouts, artichokes, etc.);
• Dried legumes.

Supplementing a healthy diet with these foods can help control this condition,” concludes Furlan.