What are the symptoms of hypokalemia?

Written by Gan Jun
Endocrinology
Updated on March 07, 2025
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When the body's blood potassium level falls below 3.5 millimoles per liter, it is called hypokalemia. Hypokalemia can cause adverse symptoms in multiple systems of the body, initially causing weakness and fatigue in the limbs, flaccid paralysis, sluggish and absent tendon reflexes, and in severe cases, respiratory difficulty. At the same time, hypokalemia can lead to a series of central nervous system damages, such as apathy, a blank stare, drowsiness, and confusion; it also causes nausea, poor appetite, abdominal distension, and intestinal paralysis among other adverse gastrointestinal phenomena. Additionally, it can lead to palpitations, and rapid atrial or ventricular arrhythmias, among other adverse phenomena. Therefore, it is crucial to provide timely and proper potassium supplementation and correction of blood potassium levels for patients with hypokalemia.

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Written by Wang Li Bing
Intensive Care Medicine Department
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How to supplement potassium for hypokalemia

Hypokalemia generally has two common methods of potassium supplementation. The first is oral potassium supplementation, and the second is intravenous potassium supplementation. Oral potassium supplementation is the safest method, for example, taking potassium chloride sustained-release tablets orally, as well as potassium chloride injection solution orally, and eating more potassium-rich vegetables and fruits. The second method is intravenous potassium supplementation. For intravenous potassium supplementation, it is important to pay attention to the patient's urine output. If the patient's urine output is adequate, intravenous potassium supplementation can be appropriately performed, and the concentration of intravenous potassium supplementation should not exceed 0.3% to prevent arrhythmias caused by hyperkalemia. (Please use medications under the guidance of a doctor.)

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Written by Wei Shi Liang
Intensive Care Unit
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Symptoms of hypokalemia

The clinical manifestations of hypokalemia are diverse, and the most life-threatening involve the cardiac conduction system and neuromuscular system. Mild hypokalemia is characterized on the electrocardiogram by flattened or absent T waves and the appearance of U waves. Severe hypokalemia can lead to fatal arrhythmias, such as ventricular tachycardia, ventricular fibrillation, or sudden death. In the neuromuscular system, the most prominent symptoms of hypokalemia are skeletal muscle relaxation, paralysis, and loss of tone in smooth muscles, leading to rhabdomyolysis. When respiratory muscles are involved, it can lead to respiratory failure. Hypokalemia can also cause insulin resistance or hinder insulin release, leading to significant glucose intolerance. A decrease in potassium excretion results in a reduced ability of the kidneys to concentrate urine, causing polyuria and low specific gravity urine.

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Intensive Care Unit
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Precautions for intravenous potassium supplementation in patients with hypokalemia

Patients with hypokalemia should closely monitor their blood potassium levels when receiving intravenous potassium supplementation, rechecking potassium levels within 1-4 hours after supplementation. Continuous electrocardiogram monitoring is necessary to closely observe any changes in the electrocardiogram and prevent life-threatening hyperkalemia. In patients with renal impairment, the potassium supplementation should be 50% of that for normal patients, and it is generally considered that the daily potassium supplementation should not exceed 100-200 mmol. For patients with severe hypokalemia, the total daily potassium supplementation can reach 240-400 mmol, but blood potassium levels should be closely monitored to prevent hyperkalemia. Peripheral administration of high-concentration potassium can irritate the vein wall, causing pain and phlebitis. Generally, it is considered that the rate of potassium supplementation through peripheral veins should not exceed 40 mmol/L.

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Written by Wang Li Bing
Intensive Care Medicine Department
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How to replenish potassium for hypokalemia

After the occurrence of hypokalemia, we usually adopt oral potassium supplementation or intravenous potassium supplementation. Oral potassium supplementation is the safest method clinically, and patients can also be advised to consume potassium-rich fruits or vegetables, etc. On the other hand, there is intravenous potassium supplementation, which must be decided based on the patient's urine output. Generally, potassium supplementation can be carried out only when the patient's urine output is more than 500 milliliters per day. However, the concentration of potassium must be diluted and not administered undiluted to prevent arrhythmias and so on.

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Written by Wei Shi Liang
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What medicine should be taken for hypokalemia?

The treatment of hypokalemia primarily involves addressing the underlying disease. Symptomatic treatment should avoid excessive potassium supplementation, which can lead to hyperkalemia. The principle of potassium supplementation is as follows: for mild hypokalemia, such as in patients showing clinical signs, oral potassium can be administered at 40-80 millimoles per day. For patients with severe hypokalemia, or those whose gastrointestinal tract cannot utilize potassium, with potassium levels less than 2.0 millimoles per liter, intravenous potassium can be provided. An initial supplementation rate of 10-20 millimoles per hour is relatively safe. In cases of severe hypokalemia with life-threatening clinical signs, a rapid increase to 40-80 millimoles can be achieved in a short period, but close monitoring is necessary.