Why does hyperkalemia cause muscle weakness?

Written by Luo Han Ying
Endocrinology
Updated on May 07, 2025
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The muscles that govern movement in our body are striated muscles, and each muscle cell in striated muscles has many receptors, which we can think of as a signal receiving and transmitting station. When we need to move, the brain nerves will send a signal to this station, which then controls muscle movement. A very important ion in muscle movement is the calcium ion. There is a receptor for calcium ions on our muscle cells, and it is related to the concentration of blood potassium. When the concentration of blood potassium is too low, a condition known as hypokalemia, or too high, known as hyperkalemia, the calcium ion receptor will be inhibited. At this point, our muscles will exhibit symptoms of muscle weakness.

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Written by Luo Han Ying
Endocrinology
1min 12sec home-news-image

What should not be eaten with hyperkalemia?

Potassium is an important element in human blood. Typically, the electrolytes we measure in blood tests include sodium, potassium, chloride, and calcium. Both low and high levels of potassium can have adverse effects on the body, especially hyperkalemia, which can cause sudden cardiac arrest and is considered dangerous in clinical settings. Patients with normal kidney function are less likely to develop hyperkalemia, which is more commonly seen in those who may have consumed Chinese herbal medicines containing high amounts of potassium for a long time. In patients with renal insufficiency, due to impaired kidney excretory function, hyperkalemia occurs more easily. Patients with hyperkalemia should generally avoid ACE inhibitors and ARB medications. For example, drugs like ACE inhibitors and spironolactone can further exacerbate hyperkalemia, so these types of medications are definitely not advisable. (The use of medications should be under the guidance of a professional doctor.)

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Written by Wei Shi Liang
Intensive Care Unit
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Does hyperkalemia cause a fast or slow heart rate?

Hyperkalemia often causes a slowed heart rate and is associated with various arrhythmias. When serum potassium is between 6.6 to 8.0 mmol/L, tented T-waves may be observed. When serum potassium levels rise rapidly, it can lead to ventricular tachycardia or even ventricular fibrillation. On the other hand, a slow increase in serum potassium can cause conduction blocks, and in severe cases, may lead to cardiac arrest. These are the heart rate changes caused by hyperkalemia, which typically result in a slower heart rate.

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Written by Wei Shi Liang
Intensive Care Unit
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The role of calcium agents in hyperkalemia

Change the excitability of autonomic cells to protect the heart. Hyperkalemia mainly affects the conduction of the heart and neuromuscular system. Typical clinical manifestations include severe bradycardia, atrioventricular block, and even sinus arrest. By using calcium agents to change the excitability of autonomic cells, we can protect the heart from the damage to the conduction system caused by hyperkalemia. This allows the potassium ions to move from outside the cell to inside the cell. While protecting the myocardium, it is also necessary to use some medications to lower blood potassium. If the blood potassium is particularly high, dialysis or continuous bedside blood filtration can be used to reduce the blood potassium to a normal range.

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Written by Wei Shi Liang
Intensive Care Unit
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What kind of urine occurs with hyperkalemia?

Primary hyperkalemia often coincides with metabolic acidosis, and in hyperkalemia-induced metabolic acidosis, paradoxical alkaline urine can occur. Once hyperkalemia occurs, it primarily affects the conduction of the heart and neuromuscular system. Typical clinical manifestations include severe bradycardia, atrioventricular conduction block, and even sinus arrest. In mild hyperkalemia, the electrocardiogram shows peaked T-waves; as potassium levels continue to rise, the PR interval prolongs, T-waves disappear, QRS complex widens, and ultimately, cardiac arrest occurs. Immediate treatment should be administered upon diagnosis to promote the excretion of potassium, maximizing the renal excretion capacity with diuretics. If drug-induced potassium excretion does not normalize levels and serum potassium exceeds 6.5 mmol/L, hemodialysis may be necessary. Additionally, some drugs can be used to shift potassium into the cells and protect cardiac function. (The use of any medication should be under the guidance of a doctor.)

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Written by Chen Li Ping
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How is hyperkalemia treated?

For hyperkalemia, commonly used clinical treatments include firstly diuretics, which increase the excretion of potassium, thus increasing its discharge from the body. Additionally, hypertonic glucose with insulin is used intravenously to facilitate the movement of potassium from outside to inside the cells. Sodium bicarbonate can also be used to correct acidosis, which can likewise reduce blood potassium levels. When hyperkalemia causes ventricular arrhythmias, calcium injections should be administered immediately to counteract the cardiac toxicity of high potassium. If these treatments do not result in significant effects and the condition is critical, emergency hemodialysis or peritoneal dialysis can be performed to lower blood potassium levels. (Medication should be administered under the guidance of a doctor.)