When serum potassium measurement is >5.5 mmol/L, it is called hyperkalemia. Because hyperkalemia often has no or very few symptoms and can suddenly lead to cardiac arrest, it should be detected early and prevented or treated promptly.

bubble_chart Etiology

The normal dietary intake of potassium is much lower than the amount excreted by the kidneys. Therefore, the causes of hyperkalemia are mostly related to decreased kidney function, which prevents effective potassium excretion, leading to an increase in potassium levels in the body. It can be divided into three categories:

1. Difficulty in renal potassium excretion, such as the oliguric phase of acute renal failure or insufficient mineralocorticoids;
2. Excessive potassium entering the body (bloodstream), such as excessive or rapid intravenous infusion, large doses of penicillin potassium salts or large volumes of stored blood, or the use of potassium-containing medications;
3. Potassium shifting from intracellular to extracellular fluid, such as hypoxia, acidosis, persistent spasm, massive hemolysis, significant internal bleeding, large hematomas, or crush syndrome, all of which can cause intracellular potassium to be released.

bubble_chart Clinical Manifestations

It depends on the primary disease, the degree and rate of potassium elevation, etc. Patients generally have no specific symptoms, mainly due to the toxic effects of potassium on the myocardium and skeletal muscles.

1. It inhibits myocardial contraction, leading to bradycardia and arrhythmia. In severe cases, ventricular fibrillation or cardiac arrest in diastole may occur. Low Na⁺, low Ca²⁺, and high Mg²⁺ can exacerbate the myocardial damage caused by hyperkalemia. The characteristic ECG changes of hyperkalemia are: early tall and peaked T waves, prolonged Q-T interval, followed by widening of the QRS complex and prolonged PR interval.
2. Neuromuscular symptoms: Early manifestations often include numbness in the limbs and around the mouth, extreme fatigue, muscle soreness, pale and cold limbs. When the serum potassium concentration reaches 7 mmol/L, limb numbness and flaccid paralysis occur, starting from the trunk, then affecting the limbs, and finally the respiratory muscles, leading to asphyxia.
3. Hyperkalemia can also cause metabolic acidosis.

bubble_chart Diagnosis

For patients with conditions that may cause hyperkalemia, remain vigilant and perform regular electrocardiogram (ECG) tests. If ECG changes indicative of hyperkalemia are observed, a diagnosis can be confirmed. Serum potassium measurements often reveal elevated potassium levels.

bubble_chart Treatment Measures

First, it is necessary to control the causes of hyperkalemia and treat the underlying disease. Once hyperkalemia is detected, potassium supplementation should be stopped immediately, and emergency measures to protect the heart should be actively taken to counteract the toxic effects of potassium, promote the transfer of potassium into cells, and eliminate excess potassium from the body to reduce serum potassium concentration.

Emergency measures:

1. Intravenous injection of calcium (10% calcium gluconate 10–20ml), which can be repeated. Calcium antagonizes potassium and can alleviate potassium's toxic effects on the myocardium. Alternatively, 30–40ml can be added to an intravenous drip.
2. Intravenous injection of 5% sodium bicarbonate solution 60–100ml, or 11.2% sodium lactate solution 40–60ml, followed by an additional injection of sodium bicarbonate 100–200ml or sodium lactate solution 60–100ml. These hypertonic alkaline sodium salts can expand blood volume, dilute serum potassium concentration, shift potassium ions into cells, correct acidosis to lower serum potassium levels, and the infused sodium also antagonizes potassium.
3. Administer 25–50% glucose 100–200ml with insulin (1U regular insulin per 4g glucose) intravenously. As glucose is synthesized into glycogen, potassium is transported into the cells.
4. Injection of atropine can have a certain effect on cardiac conduction block.
5. Dialysis therapy: Includes peritoneal dialysis and hemodialysis. If serum potassium does not decrease after the above treatments in cases of renal insufficiency, dialysis may be employed.
6. Use of cation exchange resins: 15g orally, 4 times daily, which can carry away more potassium ions from the digestive tract. It can also be added to 200ml of 10% glucose for retention enema.