Metabolic acidosis

Definition

Metabolic acidosis is a condition in which there is too much acid in the body fluids.

Alternative Names

Acidosis - metabolic

Causes

Metabolic acidosis develops when too much acid is produced in the body. It can also occur when the kidneys cannot remove enough acid from the body. There are several types of metabolic acidosis:

  • Diabetic acidosis (also called diabetic ketoacidosis and DKA) develops when substances called ketone bodies (which are acidic) build up during uncontrolled diabetes (usually type 1 diabetes).
  • Hyperchloremic acidosis is caused by the loss of too much sodium bicarbonate from the body, which can happen with severe diarrhea.
  • Kidney disease (uremia, distal renal tubular acidosis or proximal renal tubular acidosis).
  • Lactic acidosis.
  • Poisoning by aspirin, ethylene glycol (found in antifreeze), or methanol.
  • Severe dehydration.

Lactic acidosis results from a buildup of lactic acid. Lactic acid is mainly produced in muscle cells and red blood cells. It forms when the body breaks down carbohydrates to use for energy when oxygen levels are low. It can be caused by:

  • Cancer
  • Carbon monoxide poisoning
  • Drinking too much alcohol
  • Exercising vigorously for a very long time
  • Liver failure
  • Low blood sugar (hypoglycemia)
  • Medicines, such as salicylates, metformin, anti-retrovirals
  • MELAS (a very rare genetic mitochondrial disorder that affects energy production)
  • Prolonged lack of oxygen from shock, heart failure, or severe anemia
  • Seizures
  • Sepsis -- severe illness due to infection with bacteria or other germs
  • Severe asthma

Symptoms

Most symptoms are caused by the underlying disease or condition that is causing the metabolic acidosis. Metabolic acidosis itself causes rapid and deep breathing as your body tries to compensate for it. Confusion or lethargy may also occur. Severe metabolic acidosis can lead to shock or death. In some situations, metabolic acidosis can be a mild, ongoing (chronic) condition.

Exams and Tests

Your health care provider will perform a physical examination and ask about your symptoms.

These tests can help diagnose acidosis. They can also determine whether the cause is a breathing problem or a metabolic problem. Tests may include:

  • Arterial or venous blood gas
  • Basic metabolic panel, (a group of blood tests that measure your sodium and potassium levels, kidney function, and other chemicals and functions)
  • Blood ketones
  • Lactic acid test
  • Urine ketones
  • Urine pH

Other blood tests may be needed to determine the cause of the acidosis.

Other tests that may be needed to determine the cause of the acidosis include:

  • Chest x-ray
  • CT abdomen
  • Urinalysis
  • Urine pH

Treatment

Treatment is aimed at the health problem causing the metabolic acidosis. In some cases, sodium bicarbonate (the chemical in baking soda) may be given to reduce the acidity of the blood. Often, you will receive lots of fluids through your vein.

Outlook (Prognosis)

Metabolic acidosis can be dangerous if untreated. Many cases respond well to treatment. The outlook will depend on the underlying disease causing the condition.

Possible Complications

Very severe metabolic acidosis can lead to shock or death.

When to Contact a Medical Professional

Seek medical help if you have symptoms of any disease that can cause metabolic acidosis.

Prevention

Diabetic ketoacidosis can be prevented by keeping type 1 diabetes under control and responding promptly if the blood sugar stays above 250 mg/dL for over 12 hours.

References

Hamm LL, DuBose TD. Disorders of acid-base balance. In: Yu ASL, Chertow GM, Luyckx VA, Marsden PA, Skorecki K, Taal MW, eds. Brenner and Rector's The Kidney. 11th ed. Philadelphia, PA: Elsevier; 2020:chap 16.

Palmer BF. Metabolic acidosis. In: Johnson RJ, Floege J, Tonelli M, eds. Comprehensive Clinical Nephrology. 7th ed. Philadelphia, PA: Elsevier; 2024:chap 13.

Seifter JL. Acid-base disorders. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 104.

Review Date: 11/19/2023
Reviewed By: Jacob Berman, MD, MPH, Clinical Assistant Professor of Medicine, Division of General Internal Medicine, University of Washington School of Medicine, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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