What is metabolic alkalosis and what can cause

Metabolic alkalosis occurs when the pH of the blood becomes more basic than it should be, ie when it is above 7.45, which occurs in situations such as vomiting, diuretic use or excessive consumption of bicarbonate, for example.

This is a serious change as it can cause imbalance of other blood electrolytes such as calcium and potassium and cause symptoms such as weakness, headache, muscle changes, seizures or cardiac arrhythmia.

It is important that the body maintains its pH balanced, which should be between 7.35 and 7.45, so that the body's metabolism works correctly. Another worrying situation that may arise is when the pH is below 7.35, with metabolic acidosis. Know what is and what causes metabolic acidosis.

What are the causes

Metabolic alkalosis usually occurs by the loss of the H + ion in the blood or by the accumulation of sodium bicarbonate, which makes the body more basic. Some of the key situations that trigger these changes are:

• Excessive vomiting, a situation that causes loss of hydrochloric acid from the stomach;
• Stomach flushing or aspiration in the hospital;
• Excessive consumption of medicines or alkaline foods with baking soda;
• Use diuretic medicines such as Furosemide or Hydrochlorothiazide;
• Lack of potassium and magnesium in the blood;
• Excessive use of laxatives;
• Side effect of certain antibiotics, such as Penicillin or Carbenicillin, for example;
• Renal diseases, such as Bartter's Syndrome or Gitelman's Syndrome.

In addition to metabolic alkalosis, another reason for the pH of the blood to be as basic pH is respiratory alkalosis, caused by a lack of carbon dioxide (CO2) in the blood, causing it to become less acid than normal, and occurs in situations such as very rapid and deep breathing. Learn more about what it is, causes and symptoms of respiratory alkalosis.

Main symptoms

Metabolic alkalosis does not always cause symptoms and, in most cases, the symptoms of the disease that cause alkalosis. However, symptoms such as muscle spasms, weakness, headache, confusion, dizziness and convulsions can also occur, mainly caused by changes in electrolytes such as potassium, calcium and sodium.

What is compensation?

Generally, when the pH of the blood changes, the body itself tries to correct this situation as a way to avoid complications.

Compensation for metabolic alkalosis occurs primarily by the lungs, which take slower breaths to retain more carbon dioxide (CO2) and increase blood acidity.

The kidneys also try to compensate by changes in the absorption or excretion of substances in the urine, trying to eliminate more bicarbonate. However, other joint changes in the blood or kidneys such as dehydration or loss of potassium may occur, for example, especially in severely ill people, which makes it difficult for the body to correct these changes.

How to confirm

The diagnosis of metabolic alkalosis is done through tests that measure blood pH, and it is also important to evaluate how the levels of bicarbonate, carbon dioxide and some electrolytes in the blood.

The doctor will also perform the clinical evaluation to try to identify the cause. In addition, the dosage of chlorine and potassium in the urine may help to clarify the presence of renal changes in electrolyte filtration.

How is the treatment done?

To treat metabolic alkalosis, initially, it is necessary to treat its cause, be it gastroenteritis or use of certain drugs, for example. In some cases, vein hydration is required with saline solution.

Acetazolamide is a medicine that can be used to help the elimination of bicarbonate from the urine in more worrying cases. However, in very severe cases, the administration of acids directly into the vein or blood filtration through hemodialysis may be necessary.