Emergency Management of Hyperkalemia - An Overview

Introduction:

Hyperkalemia or increased blood potassium level is an electrolyte abnormality commonly identified in the emergency department. A blood potassium level greater than six milliequivalents per liter (mEq/L) can cause severe symptoms, especially when associated with low oxygen levels, and is potentially fatal. When the blood potassium level rises above normal suddenly, the heart starts beating irregularly, and muscles and nerves become weak, which may eventually lead to death. Therefore, an immediate assessment of the patient’s airway, breathing, and circulation, followed by a prompt evaluation of the heart’s condition, is essential. Treatment is initiated immediately before the diagnostic investigations if the potassium level is dangerously high (greater than six milliequivalents per liter) or if the patient is symptomatic.

What Is Hyperkalemia?

A high potassium level in the blood is called hyperkalemia. Potassium is an electrolyte naturally found in many foods and supplements. The human body needs potassium as it is an essential nutrient. The electrolytes, potassium, and sodium together help maintain normal fluid balance in our cells. In addition, potassium supports maintaining normal blood pressure. It is also essential for our nerves and muscles (including heart muscles) to work properly. However, too much potassium can be harmful and cause life-threatening conditions such as abnormal heart rhythms and paralysis. Hyperkalemia is classified based on the potassium levels in the blood as:

• Mild Hyperkalemia: Potassium levels of 5.5 – 5.9 milliequivalents per liter (mEq/L).

• Moderate Hyperkalemia: Potassium levels of 6.0 - 6.4 milliequivalents per liter (mEq/L).

• Severe Hyperkalemia: Potassium levels greater than 6.5 milliequivalents per liter (mEq/L).

What Causes High Levels of Potassium in the Blood?

There are several causes of hyperkalemia. The most common factors include the following:

1. Kidney Disease: The most common cause of high potassium levels in the blood is kidney disease. The body absorbs potassium from food, and the blood potassium level rises. The kidneys filter the excess potassium and pass them out in the urine. However, when the kidneys do not work well, they fail to filter and remove the extra potassium from the blood efficiently.

2. Diet Rich in Potassium: When a person has kidney disease or is taking certain medications, a diet with high potassium levels can cause hyperkalemia. Examples of potassium-rich food are orange juice, honeydew melon, bananas, and cantaloupe.

3. Certain Medications: Some medications prevent the kidneys from removing sufficient potassium from the blood, leading to hyperkalemia. Medications such as potassium-sparing diuretics, renin-angiotensin-aldosterone system inhibitors, Succinylcholine, and nonsteroidal anti-inflammatory drugs are associated with hyperkalemia.

4. Increased Potassium Release Into Blood: Some health problems cause the release of too much potassium in the blood. Increased breakdown of red blood cells and muscle tissue can raise blood potassium levels.

5. Burn Injuries: In severe injuries such as burn injuries, potassium is released into the blood in large amounts, causing hyperkalemia.

6. Uncontrolled Diabetes: When a person has poorly controlled diabetes, the elevated blood sugar in the body causes kidney problems leading to hyperkalemia.

7. Addison’s Disease: The production of the aldosterone hormone is less in Addison's disease. This hormone tells the kidneys to remove the extra potassium. With lesser aldosterone, such feedback signals are altered and result in hyperkalemia.

What Are the Symptoms of Mild Hyperkalemia?

Hyperkalemia is commonly diagnosed when we test the blood electrolyte levels. The normal potassium level in blood is generally between three point five and five milliequivalents per liter (mEq/L). Blood tests can identify an increase in potassium levels. Mild hyperkalemia has no clinical symptoms. However, some patients may present with mild or non-specific symptoms such as muscle weakness, nausea, numbness, and tingling sensations. These symptoms develop slowly over time and can disappear to reoccur a few weeks later. Mild hyperkalemia does not have immediate clinical significance, and emergency treatment is not needed.

What Is a Hyperkalemia Emergency?

Hyperkalemia emergency is commonly seen in patients in the emergency department with other chronic diseases such as diabetes, chronic kidney disease, renal failure, and heart disease. When the blood potassium level is greater than six milliequivalents per liter or the potassium level suddenly rises (one milliequivalent per liter above the normal range within 24 hours), it is considered a hyperkalemia emergency. Sudden or severe hyperkalemia is life-threatening. If the blood potassium levels suddenly rise to a very high level, immediate medical care is required. In case of a hyperkalemia emergency, the person experiences heart flutters, palpitations, chest pain, shortness of breath, altered sensations, nausea, or vomiting. Increased potassium levels cause deadly heart rhythm alterations (cardiac arrhythmias) and severe neuromuscular weakness. It usually leads to critical illnesses such as cardiac arrests, heart attacks, and paralysis.

How Is Hyperkalemia Diagnosed in the Emergency Department?

Emergency physicians usually test the critically ill for blood electrolyte and arterial blood gas levels (oxygen and carbon dioxide in the blood). Blood oxygen levels are low in heart problems caused by severe hyperkalemia. In most cases, hyperkalemia is diagnosed incidentally in the emergency department. Quick medical history and patient examination are carried out to identify any risk factors for hyperkalemia. For patients with risk factors, the potassium concentration is rapidly determined using point-of-care tests, followed by lab confirmation. The blood potassium levels are monitored repeatedly, and the treatment is modified depending on the test values. Immediate assessment of the patient’s airway, breathing, and circulation, followed by a prompt evaluation of the heart’s condition, is essential. An electrocardiogram (ECG) test that records the heart’s electrical activity is performed to detect heart rhythm abnormalities caused by high potassium, and treatment is initiated accordingly.

How Is a Hyperkalemic Emergency Managed?

To successfully manage severe hyperkalemia, the patient’s electrocardiogram is monitored, and blood tests are done repeatedly to test the blood potassium level. It is essential to initiate therapies that work together promptly and adjust the dose with time depending on the patient’s clinical response to the treatment. The key steps - carried out in succession or together - to manage severe hyperkalemia include the following:

1. The electrocardiogram changes caused by the high potassium levels are monitored. Treatment with intravenous calcium salts (calcium chloride or gluconate) is initiated to regularize the heart rhythm and reverse the abnormal electrocardiogram changes.

2. A severe and sudden increase in blood potassium level is initially treated with drugs that rapidly move the potassium in the blood into the body cells (intracellular space). Intravenous infusion of insulin and dextrose helps to remove excess potassium from the blood. In addition, inhalation or intravenous therapy with specific agents such as beta-adrenergic antagonists such as Albuterol helps to eliminate potassium. The process is repeated as necessary.

3. After insulin administration, the blood glucose is checked hourly to prevent low blood sugar levels. If the blood sugar levels fall below normal, glucose is administered. Sodium bicarbonate is also given if the patient has increased acid levels in the body (severe metabolic acidosis).

4. Potassium is also removed from the body using oral or rectal sodium polystyrene sulfonate.

5. If the cause of hyperkalemia remains unidentified and therapy is not possible, emergency hemodialysis is performed (a machine filters the blood and removes the extra potassium and other wastes).

Conclusion:

The blood potassium levels increase in diseases that cause potassium accumulation in the blood and prevent their elimination. Kidney diseases, uncontrolled diabetes, and certain medications commonly cause hyperkalemia. Increased blood potassium levels cause heart, nerve, and muscle problems. Severe hyperkalemia is life-threatening and requires emergency management as it can alter heart rhythm and affects heart function leading to low oxygen levels in the body. Severe hyperkalemia is frequently seen in the emergency department and requires vital signs monitoring, electrocardiograms, and blood tests. Calcium salt administration and other measures such as insulin, dextrose, and beta-adrenergic antagonists help to remove the extra potassium from the blood. The blood potassium levels and electrocardiogram changes are monitored continuously to assess treatment success and to modify the treatment according to need.