The effect of hyperkalemia on the myocardium

Written by Wei Shi Liang
Intensive Care Unit
Updated on September 01, 2024
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The primary mechanism by which hyperkalemia causes arrhythmias is due to dysfunction of myocardial conduction, which is also related to various other factors such as other myocardial lesions, failure, and ionic states. The main impact on the myocardium is on its excitability; myocardial excitability can decrease or even disappear, and its conductivity is also affected, causing a reduction in conductivity. The effect on myocardial automaticity is a decrease in automaticity. Electrocardiographically, there are manifestations such as a low P wave, prolonged PR interval, and widened QRS complex without disappearance; these are some of the presentations of hyperkalemia.

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Written by Wei Shi Liang
Intensive Care Unit
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Common Causes of Hyperkalemia

Hyperkalemia is when the serum potassium concentration exceeds 5.5 millimoles per liter. Common causes include excessive potassium intake and large doses of potassium salts, which can lead to hyperkalemia, as well as the use of stored blood. Another cause is reduced potassium excretion; in patients with renal insufficiency, reduced urine output or anuria leads to decreased renal potassium excretion. If potassium supplementation is inappropriate at this time, or if potassium-sparing diuretics are used, severe hyperkalemia can occur. Another scenario is the leakage of intracellular potassium during respiratory and metabolic acidosis, where sodium ion exchange occurs in cells, hydrogen ions enter the cells, and potassium ions leak out to the extracellular space, which can lead to increased blood potassium. These are the common causes of hyperkalemia.

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Written by Gan Jun
Endocrinology
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How to treat vomiting caused by hyperkalemia?

For patients with hyperkalemia, early symptoms include numbness in the limbs, weakness, muscle soreness, and paralysis. As the condition progresses, it can suppress myocardial function, reducing the tension of the myocardium and leading to slow heartbeats, and even cause arrhythmias and cardiac arrest. Increased release of acetylcholine can also cause nausea, vomiting, abdominal pain, and other symptoms. Patients with this condition generally also exhibit symptoms of hyperlipidemia and metabolic acidosis. For mild cases of hyperkalemia, temporary treatment may not be necessary, and symptomatic treatment such as stopping vomiting and drinking water may be sufficient. However, in acute cases, it is recommended that the patient immediately undergo dialysis or receive diuretic injections to rapidly eliminate potassium ions from the body, and to stop consuming foods and medications that contain potassium.

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Written by Chen Li Ping
Endocrinology
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Hyperkalemia

Typically, when serum potassium exceeds 5.5 mmol/L, it is referred to as hyperkalemia. However, an increase in serum potassium does not necessarily reflect an overall increase in body potassium; serum potassium can also rise when there is a deficiency of total body potassium. Therefore, in clinical practice, serum potassium is evaluated in conjunction with an electrocardiogram and medical history to determine if a patient has hyperkalemia. Hyperkalemia is an important emergency in internal medicine and can often lead to sudden cardiac arrest. It should be identified and prevented early.

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Written by Wei Shi Liang
Intensive Care Unit
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Hyperkalemia can be seen in which diseases?

Hyperkalemia is a condition where the serum potassium concentration exceeds 5.5 millimoles per liter. Common causes include excessive intake of potassium, such as high-dose potassium penicillin intravenous infusion, ingestion of potassium-containing medications, or transfusion of large amounts of stored blood, all of which can lead to hyperkalemia. Additionally, patients with renal failure who experience oliguria or anuria may have reduced potassium excretion. In such cases, inappropriate potassium supplementation or the use of potassium-sparing diuretics can lead to severe hyperkalemia. Lastly, the movement of potassium from inside the cells—during metabolic acidosis and respiratory acidosis—causes ion exchange, leading to hydrogen ions entering the cells while potassium ions leak out, resulting in hyperkalemia.

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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.