Causes of Hyperkalemia

Written by Wei Shi Liang
Intensive Care Unit
Updated on February 06, 2025
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Common causes of hyperkalemia in clinical settings include:

First, it is related to excessive intake. Generally, a high-potassium diet under normal kidney function does not cause hyperkalemia. It only occurs when there is excessive or rapid intravenous potassium supplementation, or when kidney function is impaired.

Second, hyperkalemia caused by reduced excretion. Common reasons include renal failure, lack of adrenocortical hormones, and primary renal tubular potassium secretion disorders, all of which can cause hyperkalemia.

Third, a large transfer of potassium ions from inside the cells to the outside can also cause hyperkalemia.

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Written by Wei Shi Liang
Intensive Care Unit
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How to rescue hyperkalemia

Hyperkalemia must be dealt with immediately once it occurs. The usual treatments in clinical settings include promoting potassium excretion using furosemide or other loop diuretics to maximize renal potassium excretion, or using oral or rectal potassium-eliminating agents. For life-threatening hyperkalemia with serum potassium levels greater than 6.5 mmol/L, hemodialysis is necessary. Another approach is to facilitate the shift of potassium into cells, which is done through the administration of insulin with glucose, or sodium bicarbonate along with calcium gluconate that helps protect the myocardium, thus providing treatment and protective measures for hyperkalemia.

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Written by Wei Shi Liang
Intensive Care Unit
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Treatment of Hyperkalemia with Drugs

Hyperkalemia primarily affects the conduction of the heart and muscle nerves, with typical clinical manifestations including severe bradycardia, atrioventricular block, and even sinus arrest. Once hyperkalemia occurs clinically, immediate treatment should be administered. The first approach to treatment is promoting the excretion of potassium, using furosemide or other diuretics to increase renal potassium excretion, and taking a small dose of sodium polystyrene sulfonate orally to eliminate potassium. For life-threatening severe hyperkalemia, if serum potassium is greater than 6.5 mmol/L, hemodialysis treatment is necessary. The second aspect involves shifting potassium into cells, using calcium to alter cell excitability, which can protect the heart from the damage to the conduction system caused by hyperkalemia. Additionally, using glucose with insulin and administering sodium bicarbonate can be effective. It is important to note that all the above medications should be used under the guidance of a doctor.

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Written by Chen Li Ping
Endocrinology
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The Impact of Hyperkalemia on the Heart

Typically, when serum potassium exceeds 5.5 mmol/L, it is referred to as hyperkalemia. The manifestations of hyperkalemia on the cardiovascular system usually include bradycardia and arrhythmias, but generally do not lead to congestive heart failure. Sometimes, there may be cardiac enlargement and diminished heart sounds, with characteristic changes on an electrocardiogram. Finally, when serum potassium reaches 12 mmol/L, some parts of the myocardium may be excited and recover, while others have not yet depolarized, making it very easy to cause tachycardia, flutter, ventricular fibrillation, and even cardiac arrest, leading to death. Therefore, hyperkalemia is also a major cause of sudden cardiac death. Some patients with hyperkalemia may only exhibit arrhythmias and show no neuromuscular symptoms before death, thus a rapid diagnosis is crucial. The severity of hyperkalemia is generally assessed by both the measured serum potassium concentration and changes in the electrocardiogram.

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Written by Zhao Xin Lan
Endocrinology
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How should hyperkalemia be managed?

First, it is necessary to assess the severity of the hyperkalemia, whether it is mild, moderate, or severe. For mild hyperkalemia, it can be managed by taking oral diuretics or intravenous infusion of glucose with insulin, which can normalize the potassium level. In cases of severe hyperkalemia, where blood potassium exceeds 7.5 mmol/L, there is a risk of causing cardiac arrest. Emergency measures to promote potassium excretion are required, such as hemodialysis or peritoneal dialysis. It is also necessary to counteract the myocardial depressive effects of potassium, which can be managed with the injection of calcium gluconate, along with the intravenous infusion of hypertonic glucose and insulin. (The use of medications should be conducted under the guidance of a doctor.)

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Written by Zhao Xin Lan
Endocrinology
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Clinical manifestations of hyperkalemia

The clinical manifestations of hyperkalemia are not specific. Early symptoms often include numbness in the limbs, sensory abnormalities, extreme fatigue, and muscle pain. In severe cases, there can be difficulties in swallowing, speaking, and breathing, paralysis of the limbs, and tendon reflexes may disappear. The central nervous system may show signs of restlessness, fainting, and confusion. Some may experience a slow heart rate, ventricular fibrillation, and in the most severe cases, it can lead to cardiac arrest. Other symptoms may include nausea, vomiting, diarrhea, and other gastrointestinal symptoms.