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Hyperkalemia
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.
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.)
Hyperkalemia is seen in which diseases?
When serum potassium levels exceed 5.5 millimoles per liter, it is referred to as hyperkalemia. Elevated serum potassium does not reflect an overall increase in body potassium, but due to limitations in testing methods, the clinical diagnosis of hyperkalemia still relies on combining serum potassium levels with electrocardiogram history. The causes of hyperkalemia are complex and commonly include: First, decreased renal potassium excretion, seen in acute kidney failure or insufficiency in adrenal cortical hormone synthesis and secretion, or long-term use of potassium-sparing diuretics; Second, shifts of potassium from inside the cells, often due to hemolysis, tissue damage, large-scale necrosis of tumors and inflammatory cells, shock, burns, excessive muscle contractions, acidosis, or injection of hypertonic saline or mannitol, which causes dehydration inside cells and leads to potassium leakage, resulting in hyperkalemia; Third, excessive intake of potassium-containing medications, such as high doses of potassium penicillin; Fourth, transfusion of stored blood can lead to hyperkalemia; Fifth, digitalis poisoning can cause hyperkalemia.
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.)
What are the causes of hyperkalemia?
The first reason is the excessive intake or administration of potassium, which can lead to hyperkalemia. For example, consuming foods that are very rich in potassium, or intravenously infusing solutions containing potassium. Additionally, the use of potassium salts of penicillin can also cause hyperkalemia, as well as the transfusion of stored blood, which can easily lead to hyperkalemia. Besides excessive intake and administration of potassium, diseases related to reduced excretion can also cause hyperkalemia, such as the most common instances during acute or chronic renal failure, where patients are prone to hyperkalemia. Furthermore, patients with reduced adrenal cortex function, such as aldosterone deficiency or Addison's disease, are also prone to hyperkalemia. Additionally, the use of diuretics that inhibit potassium excretion, notably spironolactone—a potassium-sparing diuretic—can also cause an increase in blood potassium levels. Another reason is a change in potassium distribution, such as when potassium moves from inside the cells to the outside, which can easily lead to hyperkalemia. This is common in cases of tissue damage, such as muscle contusion, or electrical burns, and tissue hypoxia, which also can easily lead to a change in potassium distribution, causing an increase in extracellular potassium. If hemolysis occurs in a test tube, such as if the venipuncture takes too long, or in conditions like leukocytosis or severe shaking of the blood sample, these might also lead to hyperkalemia. (The use of medications should be under the guidance of a doctor.)
Why should calcium be supplemented for hyperkalemia?
When high potassium levels trigger ventricular automaticity, it is recommended to administer calcium to counteract its cardiotoxicity. This is because during hyperkalemia, the excitability of the myocardium significantly increases. Calcium ions do not affect the distribution of potassium inside and outside the cells, but they can stabilize the excitability of the heart. Therefore, even if a patient's blood calcium level is normal, calcium should be injected immediately when there is severe arrhythmia. Calcium ions only temporarily counteract the toxicity of potassium to the heart and do not reduce the concentration of potassium in the blood. Thus, they can only serve as a short-term emergency medication. (Medication should be used under the guidance of a doctor.)
Causes of Hyperkalemia
Common causes of hyperkalemia in clinical settings include: First, it is related to excessive intake. Generally, a high-potassium diet under normal kidney function does not cause hyperkalemia. It only occurs when there is excessive or rapid intravenous potassium supplementation, or when kidney function is impaired. Second, hyperkalemia caused by reduced excretion. Common reasons include renal failure, lack of adrenocortical hormones, and primary renal tubular potassium secretion disorders, all of which can cause hyperkalemia. Third, a large transfer of potassium ions from inside the cells to the outside can also cause hyperkalemia.
How should hyperkalemia be managed?
First, it is necessary to assess the severity of the hyperkalemia, whether it is mild, moderate, or severe. For mild hyperkalemia, it can be managed by taking oral diuretics or intravenous infusion of glucose with insulin, which can normalize the potassium level. In cases of severe hyperkalemia, where blood potassium exceeds 7.5 mmol/L, there is a risk of causing cardiac arrest. Emergency measures to promote potassium excretion are required, such as hemodialysis or peritoneal dialysis. It is also necessary to counteract the myocardial depressive effects of potassium, which can be managed with the injection of calcium gluconate, along with the intravenous infusion of hypertonic glucose and insulin. (The use of medications should be conducted under the guidance of a doctor.)
Can hyperkalemia be cured?
The main focus is on the cause of hyperkalemia. If hyperkalemia is due to consuming foods rich in potassium, administration of potassium-containing solutions, transfusion of stored blood, use of potassium-sparing diuretics like spironolactone, or prolonged venipuncture causing severe shaking of the blood sample during transport, addressing these causes can prevent the occurrence of hyperkalemia. If hyperkalemia is caused by certain diseases, such as renal failure or adrenal insufficiency, active treatment of the underlying disease is required. If the renal failure is acute, recovery of kidney function might prevent the recurrence of hyperkalemia. However, if there is chronic renal insufficiency, there tends to be a higher recurrence rate of hyperkalemia. Therefore, whether hyperkalemia can be cured largely depends on identifying the underlying cause.
The impact of hyperkalemia on the heart
The effects of hyperkalemia on the heart mainly manifest in the following ways: First, it affects the excitability of the myocardium, as hyperkalemia can cause reduced or even absent myocardial excitability; second, it impacts myocardial conductivity. In hyperkalemia, due to the reduced resting potential, the amplitude and speed of the action potential's phase zero decrease, leading to slowed excitability spread and reduced conductivity; third, it influences the automaticity of the myocardium. In hyperkalemia, due to slowed automatic depolarization, the automaticity is reduced. Additionally, hyperkalemia produces characteristic changes in the electrocardiogram, such as depression or disappearance of the P wave, prolongation of the PR interval, widening of the S wave, and narrowing and peaking of the T wave, which are the main changes in the electrocardiogram due to hyperkalemia.