Lactic acidosis is a serious medical condition that happens when lactic acid builds up in your blood faster than your body can remove it. This causes your blood to become too acidic, which can affect how your organs work. In this article, we explain what lactic acidosis is, what causes it, how to recognize the symptoms, and when to seek medical help in Canada.
What Is Lactic Acidosis?
Your body produces lactic acid naturally during normal activity. Usually, your liver breaks it down quickly and removes it from your bloodstream. However, when too much lactic acid builds up, your blood pH drops below normal levels, and lactic acidosis develops.
Lactic acidosis is a form of metabolic acidosis. Metabolic acidosis means your body’s chemistry is out of balance — specifically, your blood has become too acidic. This can interfere with many of your body’s normal processes, from breathing to heart function.
There are two main types of lactic acidosis. Type A is the most common and is caused by a lack of oxygen reaching your tissues. Type B is less common and happens without oxygen deprivation — it can be linked to medications, diseases, or other conditions.
Common Causes of Lactic Acidosis
Many different things can trigger lactic acidosis. Understanding the causes can help you and your family doctor identify your risk early. Some causes are sudden and serious, while others develop slowly over time.
Low Oxygen Levels (Type A)
When your body’s tissues do not get enough oxygen, they switch to a different way of producing energy. This process creates more lactic acid than usual. Conditions that cut off oxygen supply are the most common triggers.
Common causes of Type A lactic acidosis include:
Severe infections (sepsis)
Heart attack or heart failure
Severe asthma or respiratory failure
Shock (when blood pressure drops dangerously low)
Severe blood loss or trauma
Carbon monoxide poisoning
Non-Oxygen-Related Causes (Type B)
Type B lactic acidosis develops without a shortage of oxygen. Instead, it is linked to problems with how your body processes energy. Therefore, it can be harder to detect at first.
Common causes of Type B lactic acidosis include:
Certain medications, particularly metformin (used for type 2 diabetes)
Liver disease or liver failure
Kidney disease
Cancer, especially blood cancers like leukemia or lymphoma
Heavy alcohol use
HIV and some antiretroviral medications
Rare inherited metabolic disorders
According to Mayo Clinic, metformin-associated lactic acidosis is rare but well-documented. Your doctor will monitor your kidney function closely if you take metformin.
Recognizing the Symptoms of Lactic Acidosis
The symptoms of lactic acidosis can range from mild to life-threatening. They often come on quickly, especially when triggered by a serious event like sepsis or heart failure. As a result, knowing the warning signs is very important.
Early Symptoms
In the early stages, lactic acidosis may feel like general tiredness or an upset stomach. These symptoms are easy to overlook. However, they should not be ignored — especially if you have a known risk factor.
Early warning signs include:
Unusual fatigue or weakness
Nausea and vomiting
Stomach pain or cramping
Muscle aches and cramps
Headache
Severe Symptoms
As lactic acid continues to build up in the blood, symptoms become more serious. At this stage, the condition is a medical emergency. Call 9-1-1 or go to your nearest emergency room right away.
Severe symptoms include:
Rapid, shallow breathing (sometimes called Kussmaul breathing)
Rapid heart rate
Low blood pressure
Confusion or difficulty concentrating
Yellowing of the skin or eyes (jaundice), if the liver is involved
Loss of consciousness
For more information on how the body manages acid-base balance, visit Healthline’s overview of metabolic acidosis.
How Is Lactic Acidosis Diagnosed?
Doctors diagnose lactic acidosis through blood tests. A blood test measures the level of lactate (lactic acid) in your blood. A normal lactate level is below 2 mmol/L. A level above 4 mmol/L, combined with a low blood pH, typically confirms a diagnosis of lactic acidosis.
In addition to lactate levels, your doctor will likely order:
A complete blood count (CBC)
Kidney and liver function tests
Blood glucose (sugar) levels
Arterial blood gas (ABG) to measure blood pH
Electrolyte levels
These tests help identify the underlying cause. Finding the cause is just as important as treating the acidosis itself. Without addressing the root problem, lactic acidosis is likely to return.
Treatment for Lactic Acidosis
Treatment for lactic acidosis always focuses on correcting the underlying cause. There is no single treatment that works for every case. Instead, doctors tailor the approach based on what triggered the condition.
Emergency Treatment
When lactic acidosis is severe, treatment happens in a hospital — often in an intensive care unit (ICU). The goal is to restore oxygen to tissues and stabilize vital signs as quickly as possible.
Common emergency treatments include:
Oxygen therapy or mechanical ventilation to improve breathing
IV fluids to restore blood pressure and circulation
Medications to treat the underlying infection or heart failure
Dialysis to support the kidneys and help clear lactic acid
Sodium bicarbonate in some cases, to help raise blood pH
Treating the Underlying Cause
For milder or chronic cases, treatment targets the root problem. For example, if a medication like metformin is causing the buildup, your doctor may reduce the dose or switch you to a different drug. If liver disease is the cause, managing that condition becomes the priority.
Furthermore, lifestyle changes may help reduce the risk of future episodes. Limiting alcohol, managing diabetes carefully, and keeping regular follow-up appointments with your family doctor all play an important role.
Who Is at Risk for Lactic Acidosis in Canada?
Lactic acidosis can affect anyone, but certain groups face a higher risk. If you fall into one of these categories, it is worth discussing your risk with your family doctor or primary care provider.
Higher-risk groups include:
People with type 2 diabetes who take metformin, especially if they also have kidney or liver problems
People living with HIV who take nucleoside reverse transcriptase inhibitors (NRTIs)
People with chronic liver or kidney disease
Those with a history of heavy alcohol use
People with cancer, particularly blood cancers
Anyone with a condition that reduces blood flow or oxygen, such as heart failure
In Canada, your provincial health plan covers most of the blood tests and hospital care needed to diagnose and treat lactic acidosis. If you are concerned about your risk, a visit to your family doctor or a walk-in clinic is a good first step. Health Canada also provides resources on managing chronic conditions that may increase your risk.
When to See a Doctor
You should see a doctor right away if you develop any severe symptoms of lactic acidosis — especially rapid breathing, confusion, or chest pain. These are signs of a medical emergency. Call 9-1-1 or go to your nearest emergency room immediately.
For milder concerns, visit your family doctor or a walk-in clinic. This is especially important if you take metformin, have kidney or liver disease, or drink alcohol heavily. Tell your doctor about any new or unusual fatigue, muscle cramps, or stomach pain.
Regular check-ups are one of the best ways to catch problems early. Your doctor can monitor your lactate levels and kidney function if you are at risk. Most provincial health plans in Canada cover these routine tests without extra cost to you.
Disclaimer: This article is for general information only. Always speak with a qualified healthcare provider before making any decisions about your health or treatment.
Frequently Asked Questions About Lactic Acidosis
What are the first signs of lactic acidosis?
The first signs of lactic acidosis often include unusual fatigue, nausea, stomach pain, and muscle cramps. These early symptoms can be easy to overlook, but they are important warning signs — especially if you have a known risk factor. If you notice these symptoms and feel unwell, contact your family doctor or visit a walk-in clinic.
Can metformin cause lactic acidosis?
Yes, metformin can cause lactic acidosis in rare cases, particularly in people with kidney or liver problems. This is why doctors monitor kidney function regularly in patients who take this diabetes medication. If you have concerns about metformin and lactic acidosis, speak with your family doctor before stopping any medication.
Is lactic acidosis life-threatening?
Lactic acidosis can be life-threatening, particularly when it is severe and caused by a serious condition like sepsis or heart failure. The faster treatment begins, the better the outcome tends to be. If you or someone you know has severe symptoms, call 9-1-1 immediately.
How is lactic acidosis treated?
Treatment for lactic acidosis focuses on finding and correcting the underlying cause. In severe cases, this may involve oxygen therapy, IV fluids, and hospital care. For milder cases linked to medications or chronic conditions, your doctor may adjust your treatment plan to reduce lactic acid buildup.
What is the difference between lactic acidosis and regular muscle soreness?
Regular muscle soreness after exercise involves a temporary, mild rise in lactic acid that your body clears quickly and safely. Lactic acidosis, on the other hand, is a medical condition where lactic acid builds up persistently in the blood and lowers its pH. Unlike muscle soreness, lactic acidosis causes systemic symptoms like rapid breathing, confusion, and nausea.
Can lactic acidosis be prevented?
In many cases, lactic acidosis can be prevented by managing the conditions that cause it. For example, keeping diabetes and kidney disease well-controlled, limiting alcohol intake, and attending regular check-ups with your family doctor all help reduce your risk. If you take medications linked to lactic acidosis, follow your doctor’s monitoring schedule closely.
Key Takeaways
Lactic acidosis happens when lactic acid builds up in the blood faster than the body can clear it.
There are two main types: Type A (caused by low oxygen) and Type B (caused by medications, disease, or other factors).
Common causes include sepsis, heart failure, liver disease, heavy alcohol use, and certain medications like metformin.
Early symptoms include fatigue, nausea, and muscle cramps. Severe symptoms — like rapid breathing and confusion — are a medical emergency.
Diagnosis relies on blood tests measuring lactate levels and blood pH.
Treatment focuses on correcting the underlying cause, not just managing the acid levels.
Higher-risk Canadians should discuss regular monitoring with their family doctor or at a walk-in clinic.
Always consult a healthcare professional if you have concerns about lactic acidosis or any related symptoms.
