The severity of hyperkalemia is related to the severity of potassium deficiency. For mild hyperkalemia, the symptoms are generally mild; for moderate hyperkalemia, patients are mainly characterized by weakness, abdominal distension as well as nausea; for severe hyperkalemia, cardiac arrest may be induced, which is life-threatening. 1. Mild hyperkalemia: generally refers to the blood potassium concentration is lower than 3.5mmol/L and higher than 3.0mmol/L. In this case, patients usually do not have obvious symptoms, and most of them only show weakness. 2. Moderate hypokalemia: the blood potassium concentration is lower than 3.0mmol/L and higher than 2.5mmol/L. In this case, the patient may have weakness, abdominal distension, nausea, loss of appetite, dizziness, and so on. 3. Severe hypokalemia: generally refers to the blood potassium concentration is lower than 2.5mmol/L, this condition will not only show general weakness, but also may have difficulty in breathing and swallowing, and may even cause cardiac arrhythmia, which may lead to sudden death by cardiac arrest in severe cases. Since severe low potassium can pose a threat to life safety, it is important to carry out standardized treatment under the guidance of a doctor in a timely manner.