Hyperkalemia - Causes and Signs of Hyperkalemia

Depending on its severity, hyperkalemia can be:

• mild;
• moderate;
• severe;
• extremely severe.

Causes

Usually hyperkalemia develops if the kidneys are unable to excrete potassium in sufficient quantities. The most common cause of mild hyperkalemia is taking medications that block the excretion of potassium from the body.

This is caused by treatment with:

• triamterene;
• spironolactone;
• angiotensin-converting enzyme inhibitors.

The kidneys regulate the concentration of potassium in the body. If they are functioning normally, the normal diet contains enough potassium to keep the body functioning well.

Addison's disease can cause this condition, in which the adrenal glands are unable to produce enough hormones, causing the kidneys to excrete potassium from the body.

The condition can develop when large amounts of potassium are suddenly released from cells.

This happens, for example:

• when a large amount of muscle tissue is destroyed (as in crush injuries);
• with a cocaine overdose or severe burns. In these cases, potassium enters the bloodstream quickly, exceeding the kidneys' ability to excrete it. Life-threatening hyperkalemia develops.

Symptoms

Hyperkalemia symptoms are very minor. They mainly manifest themselves in changes on the electrocardiogram:

• various cardiac arrhythmias;
• ventricular tachycardias;
• sharpening of the T wave on the electrocardiogram;
• increase in the P-R interval on the electrocardiogram;
• increase in the ORS interval on the electrocardiogram.

Diagnostics

Chronic hyperkalemia in almost all cases is associated with a violation in the process of potassium excretion from the body. If the cause of the disease is unclear and the patient does not show any symptoms, pseudohyperkalemia can be immediately suspected. Then severe chronic or acute renal failure is excluded.

During the anamnesis:

• The fact of the patient's intake of drugs that could affect the balance of potassium in the body is clarified, and whether hyperkalemia could be caused by excessive intake of potassium with food.
• During physical examination, special attention is paid to signs of changes in the volume of extracellular fluid and BCC, diuresis is determined.
• The severity of hyperkalemia is assessed by a combination of symptoms, ECG abnormalities and plasma potassium concentration.

For differential primary diagnosis of adrenal insufficiency and hyperaldosteronism, the following is determined:

• renin level;
• aldosterone level in plasma.

These studies are carried out in the supine and standing positions. Preparation for these studies is carried out over the course of 3 days. Their purpose is to create moderate hypovolemia. For this, loop diuretics are prescribed and sodium intake is limited (no more than 10 mmol/day).

Treatment

The hematologist chooses the treatment methods, focusing on:

• sources of the disease;
• severity.

In cases where the blood plasma contains potassium, which exceeds 6 mmol/l and there is a high risk of cardiac arrest. It is necessary to urgently reduce it to a safe level. For this, the patient is administered a calcium gluconate or chloride solution intravenously, which protects the heart, which begins to act within five minutes. If the expected effect is not achieved during this period of time, and the ECG does not show positive changes, the dose of calcium gluconate or chloride is repeated. These drugs can act for 3 hours. When their period of action ends, the patient is given a calcium solution again.

When treating severe hyperkalemia in people with renal dysfunction, it is necessary to quickly remove excess potassium from the body.

For this, the following are used:

• hemofiltration;
• hemodialysis without potassium.

These methods are used if it is not possible to eliminate the cause of excess potassium and in cases where other measures do not help.

Therapy that prevents complications and stops the development of the disease is based on the administration of:

• glucose;
• salbutamol;
• insulin.

Patients are prescribed sodium polystyrene sulfate (ion exchange resin), which contains sorbitol, orally or rectally. If the patient's kidneys are functioning normally, furosemide is used to remove excess potassium from the body with urine.

Prevention

Preventive measures to prevent the disease are based on:

• limiting potassium intake;
• refusing potassium-containing drugs;
• using thiazide and loop diuretics to intensively remove potassium with urine;
• using special treatment for pathological hyperkalemia.