Metabolic alkalosis happens when the blood pH becomes more basic than it should be, that is, when it is above 7.45, which arises in situations such as vomiting, use of diuretics 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 balanced pH, which should be between 7.35 and 7.45, for the body’s metabolism to work properly. Another worrying situation that can arise is when the pH is below 7.35, with metabolic acidosis. Know what is and what causes metabolic acidosis.
Possible causes
Generally, metabolic alkalosis is caused 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 main situations that cause these changes are:
- Excessive vomiting, a situation that causes loss of hydrochloric acid from the stomach;
- Stomach lavage or aspiration in hospital;
- Excessive consumption of alkaline medicines or foods, with sodium bicarbonate;
- I use diuretic drugs such as Furosemide or Hydrochlorothiazide;
- Lack of potassium and magnesium in the blood;
- Excessive use of laxatives;
- Side effects of certain antibiotics, such as Penicillin or Carbenicillin, for example;
- Kidney diseases such as Bartter’s Syndrome or Gitelman’s Syndrome.
In addition to metabolic alkalosis, another reason for the blood pH to remain at the basic pH is respiratory alkalosis, caused by a lack of carbon dioxide (CO2) in the blood, causing it to become less acidic than normal, and it happens in situations like breathing very quickly and deeply. Learn more about what respiratory alkalosis is, causes and symptoms.
Main symptoms
Metabolic alkalosis does not always cause symptoms, and most often it is the symptoms of the disease that cause the alkalosis. However, symptoms such as muscle spasms, weakness, headache, mental confusion, dizziness and seizures may also appear, mainly caused by changes in electrolytes such as potassium, calcium and sodium.
What is compensation?
Generally, when the blood pH changes, the body itself tries to correct this situation, in order to avoid complications.
Compensation for metabolic alkalosis occurs mainly through the lungs, which start breathing more slowly to retain more carbon dioxide (CO2) and increase blood acidity.
The kidneys also try to compensate, through changes in the absorption or excretion of substances in the urine, trying to get rid of more bicarbonate. However, other changes may occur together, in the blood or kidneys, such as dehydration or loss of potassium, for example, especially in seriously ill people, which hinders the body’s ability to correct these changes.
How to confirm the diagnosis
The diagnosis of metabolic alkalosis is made through tests that measure the blood pH, and it is also important to assess the levels of bicarbonate, carbon dioxide and some blood electrolytes.
The doctor will also perform a clinical evaluation to try to identify the cause. In addition, the measurement of chlorine and potassium in the urine can help to clarify the presence of renal alterations in the filtration of electrolytes.
How is the treatment done
To treat metabolic alkalosis, initially, it is necessary to treat its cause, whether it is gastroenteritis or the use of certain medications, for example. In some cases, hydration through the vein with saline solution is necessary.
Acetazolamide is a drug that can be used to help eliminate bicarbonate from the urine in more worrying cases, however, in very serious cases, it may be necessary to administer acids directly into the vein or to filter the blood through hemodialysis.
