Metabolic Acidosis: Symptoms, Causes & Treatment

Metabolic acidosis is a condition in which acid builds up in the blood or the body loses too much bicarbonate. Bicarbonate is a substance that helps neutralize acids and keep blood pH within a healthy range.

This condition can cause symptoms such as nausea, vomiting, confusion, tiredness, and weakness. However, symptoms are not always present and may be hard to recognize.

Metabolic acidosis can happen for several reasons, including diabetic ketoacidosis, lactic acidosis, severe diarrhea, or kidney failure. Diagnosis is usually made with an arterial blood gas test, and treatment depends on the underlying cause.

Main symptoms

The main symptoms of metabolic acidosis are:

• Nausea and vomiting;

• Loss of appetite;

• Tiredness and weakness;

• Increased heart rate;

• Fast, deep breathing;

• Headache;

• Confusion.

It is important to note that symptoms are not always present and may be difficult to identify.

In addition, symptoms of metabolic acidosis can vary depending on the cause. They may affect breathing, the brain, heart function, and the body’s metabolism.

Confirming diagnosis

Metabolic acidosis is diagnosed by a general practitioner or nephrologist through an evaluation of symptoms, health history, and blood tests, especially an arterial blood gas test.

This test is essential for diagnosing metabolic acidosis, which is defined by a blood pH below the normal range of 7.35 to 7.45, along with low bicarbonate (HCO3) levels. PaCO2 may be low as the body tries to compensate by breathing faster.

In addition, other blood tests and a urine test may be needed to investigate the cause of metabolic acidosis and guide the most appropriate treatment.

Metabolic acidosis vs respiratory acidosis

Metabolic acidosis is a decrease in blood pH caused by an increase in acids or a decrease in bicarbonate in the body.

Respiratory acidosis is a decrease in blood pH caused by an increase in carbon dioxide (CO2) due to hypoventilation. Hypoventilation means breathing is too shallow or too slow to meet the body’s needs.

Possible causes

The main causes of metabolic acidosis are:

1. Diabetic ketoacidosis

Metabolic acidosis can be a complication of type 1 diabetes. When diabetes is not treated properly, the body can produce and build up acidic ketone bodies.

2. Severe diarrhea or improper use of laxatives

Severe diarrhea or improper use of laxatives can cause the body to lose too much sodium bicarbonate through bowel movements. Sodium bicarbonate is an essential substance that helps neutralize acids in the body.

3. Lactic acidosis

Lactic acidosis is the buildup of lactic acid in the blood. This happens when the body produces more lactic acid than it can clear.

This condition may occur in cases of cancer, excessive alcohol intake, heart failure, severe anemia, severe asthma, prolonged hypoxia, sepsis, or liver failure, for example.

4. Alcohol poisoning

Poisoning from alcohols such as methanol or ethylene glycol can increase the body’s production of acidic compounds and lead to metabolic acidosis.

5. Kidney failure

Kidney failure can also cause metabolic acidosis because the kidneys are unable to maintain the body’s normal pH balance. This happens when they cannot remove excess acid or reabsorb enough bicarbonate.

Treatment options

Treatment for metabolic acidosis should be guided by a general practitioner or nephrologist and varies depending on the cause. It usually requires hospitalization.

The main treatments for metabolic acidosis are:

• Administration of insulin, especially in cases of diabetic ketoacidosis;

• Hemodialysis, in cases of alcohol poisoning, and antidotes may also be used;

• IV fluids or oral rehydration salts, in cases of fluid loss due to diarrhea;

• Dialysis, in cases of kidney failure.

In addition, the doctor may recommend medications such as sodium bicarbonate or potassium citrate to help increase base levels in the blood and reduce acidity.

In severe cases of metabolic acidosis, intravenous bicarbonate may be needed to quickly correct the body’s acidity.

Diet for metabolic acidosis

The diet for metabolic acidosis should prioritize fruits, vegetables, nuts, and plant-based proteins, as these foods do not tend to increase the body’s acidity. 

It is also important to reduce the consumption of meat, fish, eggs, cheese, and alcoholic beverages, and to consult a registered dietitian for a nutrition plan adapted to the person’s needs.