Lactic acidosis is common in hospitalized patients who are very sick. In the last 15 years, I have treated many hospitalized patients who had lactic acidosis at one point or another. I am wiring this article based on my personal experience as well as a thorough review of medical literature.
In this article, I will explain what lactic acidosis is and what causes it. I will also describe some common diseases and conditions that cause lactic acidosis in hospitalized patients, and I will explain how to lower lactic acid levels in those situations.
What is lactic acidosis?
When lactic acid levels in the blood go up abnormally, it is called lactic acidosis. Lactic acid is an organic chemical that is produced during normal metabolism. Whenever your body needs extra energy but does’t have enough oxygen to burn fuel fast, it goes into the lactic acid pathway.
Normally, your body uses oxygen to burn fuel. All carbon-based fuels produce carbon dioxide and water when burned in the presence of oxygen. When oxygen is not available, your body can still use the fuel to produce energy, but the burning is incomplete. It still produces some energy, but the fuel is converted to lactic acid instead of carbon dioxide and water. This process is called the lactic acid pathway.
When the supply of oxygen is restored, lactic acid can be combined with oxygen to produce more energy, and eventually it is converted to carbon dioxide and water. Most of this conversion takes place in your liver, but other vital organs often participate to different degrees. When there is too much lactic acid in the blood, but the need for energy no longer exists, your liver may also convert the lactic acid back to glucose. Glucose is the main fuel that your body uses. Your liver handles and converts many different chemicals inside your body. These types of chemical reactions inside your liver are part of your metabolism. Your liver metabolizes lactic acid based on what your body needs.
Let’s look at an example of how lactic acid is formed and metabolized during everyday activity. When you start running, your leg muscles need more energy. They start to burn fuel, and your breathing increases to supply more oxygen. As you keep running, even increased breathing is not enough to supply all the oxygen. Your leg muscles start to supplement the energy needs by utilizing the lactic acidosis pathway. The lactic acid levels in your blood go up slightly. When you take a rest, your body combines the lactic acid with oxygen, and your lactic acid levels go back down.
The formation of lactic acid is normal and necessary in the short term, but when it starts to accumulate in large amounts, it indicates trouble.
What causes lactic acidosis?
When lactic acid starts to accumulate in your body, it is an indication that your body is in a lot of stress. In practice, both the production and conversion of lactic acid in the liver is affected whenever there is a significant accumulation of lactic acid in the body. A lack of oxygen, low blood pressure, liver problems, tissue injury, and other similar conditions all cause lactic acidosis of different degrees. We will look into common causes of lactic acidosis in hospitalized patients and explore what they signify.
Lactic acidosis in patients with sepsis:
Sepsis is a very common cause of lactic acidosis in hospitalized patients.
If you would like to learn the details about sepsis and septic shock, you can read this article: “Low blood pressure and a fever: think about sepsis.”
Sepsis is your body’s overwhelming response to an infection. With sepsis, your body is under a tremendous amount of stress, which triggers uncontrolled and unregulated inflammation while trying to fight the infection. This overwhelming inflammation needs a lot of energy. The demand for oxygen goes up, but effective oxygen delivery to the organs and tissues suffers. Your body starts to produce energy by converting fuel into lactic acid.
The level of lactic acid in the blood is very important when treating hospitalized patients with sepsis. It is the most reliable indicator of how serious the situation is. When lactic acid levels are very high to begin with, you know that the patient is very sick. If the treatment of severe sepsis is successful, lactic acid levels should go down. If it does not, the treatment needs to be modified.
Lactic acidosis in bowel ischemia
Bowel ischemia is a condition where blood flow to your intestines gets compromised. Sudden bowel ischemia is a medical emergency. People usually get sudden, severe abdominal pain, getting very sick.
With the lack of blood, oxygen supply goes down, and lots of lactic acid is produced. Whenever someone has severe abdominal pain with high lactate, the possibility of bowel ischemia needs to be considered. Bowel ischemia can kill you quickly if not treated urgently.
Lactic acidosis after a heart attack
A heart attack is caused by a lack of blood flow to the heart muscles. Heart muscles lose the supply of oxygen when blood flow stops. They start making large amounts of lactic acid. At the same time, a major heart attack may also decrease the blood supply of your whole body. Your blood pressure may go down. When that happens, your whole body may start making lactic acid, and severe lactic acidosis occurs.
Lactic acidosis after carbon monoxide poisoning
Carbon monoxide is a colorless and odorless gas that is produced when carbon-based fuel is burned inside a confined space. There is a limited amount of oxygen inside a confined space. At first, 2 molecules of oxygen combine with each molecule of carbon to make carbon dioxide. When oxygen becomes limited, one carbon molecule combines with only one molecule of oxygen, and carbon monoxide is formed.
When you breathe in carbon monoxide, you get carbon monoxide poisoning. Carbon monoxide combines with the red oxygen-carrying component of blood called hemoglobin. When this happens, there will not be enough free hemoglobin to carry oxygen.
Normally, when your oxygen level is low, your blood becomes less red, and your fingers may look bluish. However, with carbon monoxide poisoning, your blood becomes very bright red or even pink. Even a pulse ox oxygen meter will be deceived by the color of blood, instead showing normal oxygen levels.
Read [Link“Oxygen level with pneumonia”Link] if you would like to know how a pulse ox meter works.
The lack of oxygen forces your body to go into severe lactic acidosis.
Lactic acidosis in patients after a seizure
A seizure is caused by a sudden misfire in the brain that causes involuntary rapid muscle contractions. During a tonic-clonic seizure, the body tenses up immensely, triggering vigorous rhythmic movement.
Lactic acid levels increase immediately after a seizure, since vigorous muscle contractions need a lot of energy. Using the lactic acidosis pathway is the only way your body can generate so much energy in such a short period of time.
When there is doubt about whether someone actually had a seizure or a loss of consciousness for some other reason, testing the lactic acid level helps. A high lactic acid level helps confirm the diagnosis of a major seizure.
Lactic acidosis caused by certain medications
There are certain medications that can cause lactic acidosis in susceptible individuals. One such common medication is called Metformin. It is commonly used by people with type 2 diabetes. Lactic acidosis may happen with an overdose of Metformin, but it may also happen to some people with a normal dose.
In susceptible individuals, these types of medications interfere with the body’s ability to burn fuel using oxygen. They damage the structures called mitochondria, which are the powerhouses of your cells. Your body cells then utilize the lactic acid pathway to generate energy, causing severe lactic acidosis.
Lactic acidosis from alcoholism
Differing from the other causes of lactic acidosis so far, lactic acidosis from alcoholism is not caused by an overproduction of lactic acid. Alcohol abuse may damage your liver, reducing the ability of your liver to metabolize lactic acid produced under normal conditions. Lactic acid begins to accumulate even when there is no lack of oxygen.
In conclusion, lactic acidosis may be caused by many different conditions. A high lactic acid level could be a sign of grave danger with many diseases and conditions, and it needs an urgent diagnosis and treatment.
References
https://air.unimi.it/retrieve/handle/2434/675697/1382486/rccm.201812-2342oc.pdf
https://www.sciencedirect.com/science/article/pii/S1059131116300772
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6174180/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3222024/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5066311/
https://pubmed.ncbi.nlm.nih.gov/31361914/
https://www.metabolismjournal.com/article/S0026-0495(15)00306-6/fulltext#secst0055