Metabolic acidosis is a condition in which the acid level in the blood is higher than normal. By definition, this condition is different from acidosis due to breathing problems, which is known as respiratory acidosis.
What is going on in the body?
The lungs and kidneys work hard to maintain a delicate balance between acid and base in the blood, the body's cells, as well as in the fluid outside the cells. Any of a number of disease processes can lead to production of more acid of various types than the kidneys can eliminate. Alternatively, the kidneys themselves may not work. Either of these situations can cause high acid levels in the blood, that is, metabolic acidosis.
What are the causes and risks of the disease?
Metabolic acidosis can arise from any of a long list of sources. Some of the more common are:
some types of kidney disease or kidney failure
an overdose of aspirin
ingestion of ethylene glycol, a chemical found in antifreeze
shock, a critical condition characterized by poor blood flow throughout the body, most often due to overwhelming infection (sepsis), blood loss, or heart failure
diabetic ketoacidosis, a condition that occurs in certain people with uncontrolled type 1 diabetes mellitus
medications, such as a diuretic or "fluid pill" called acetazolamide. A diabetes medication called metformin (i.e., Fortamet, Glucophage, Glumetza, Riomet) occasionally causes metabolic acidosis.
- severe diarrhea
What can be done to prevent the disease?
Metabolic acidosis often cannot be prevented. Medications should be taken as prescribed. Those with diabetes should check their blood sugar levels regularly. Antifreeze and other harmful chemicals should be kept out of the reach of young children. Those with diarrhea should drink a lot of fluids to avoid dehydration.
How is the disease diagnosed?
Metabolic acidosis may be suspected after a history and physical exam. The diagnosis is often confirmed with a blood test called arterial blood gases. This test will demonstrate an increased level of acid in the blood, and may give clues to the cause.
Further tests may also be needed to diagnose the underlying problem. For example, a blood glucose test can help diagnose diabetes. Blood tests known as the BUN and creatinine level can help diagnose kidney failure. Other tests are also possible.
Long Term Effects
What are the long-term effects of the disease?
Most people recover fully once the cause of the metabolic acidosis is treated, and have no long-term effects. Severe acidosis may result in coma or death if not corrected.
What are the risks to others?
Metabolic acidosis is not contagious and does not put other people at risk.
What are the treatments for the disease?
The main goal of treatment is to correct the underlying problem that created the metabolic acidosis. Once the cause is treated, the body will naturally correct the acid level. For example, someone with diabetic ketoacidosis needs insulin, a natural hormone that can be given as a medication to lower the blood sugar level. Those who have shock due to a severe infection may need antibiotics or surgery. In some cases, dialysis is required. Dialysis is a procedure to filter the blood. It is usually done when the kidneys fail or after a severe drug overdose.
What are the side effects of the treatments?
If the underlying cause of the metabolic acidosis can be treated, the acid levels in the body usually return to normal. In these cases, no further treatment may be needed. A person with irreversible kidney failure may need dialysis for the rest of his or her life, or until a kidney transplant becomes available.
What happens after treatment for the disease?
If the underlying cause of the metabolic acidosis can be treated, the acid levels in the body usually return to normal. In these cases, no further treatment may be needed. Those with permanent kidney failure may need dialysis for the rest of their lives.
How is the disease monitored?
Repeated blood tests can be done to follow the acid level in the blood if needed. Other monitoring relates to the cause. For example, someone with diabetes needs to monitor his or her blood sugar levels regularly for life. Any new or worsening symptoms should be reported to the healthcare professional.
Harrison's Principles of Internal Medicine, 1998, Fauci et al.