What causes acidosis: Understanding the different types and triggers

October 2, 2025 •

4 min read

With a healthy blood pH range between 7.35 and 7.45, even slight deviations can signal a serious health issue. This condition, known as acidosis, is caused by an excess of acid in the body's fluids. What causes acidosis, and how do different factors contribute to this dangerous imbalance? Let's explore the underlying mechanisms and potential triggers.

Quick Summary

Acidosis, an imbalance caused by too much acid in the body, is primarily divided into metabolic and respiratory types, each with distinct causes. Metabolic acidosis stems from kidney problems, diabetes, or toxin ingestion, while respiratory acidosis is due to poor lung function and carbon dioxide retention. Understanding the specific trigger is crucial for proper diagnosis and treatment.

Key Points

Two Primary Types: Acidosis is classified as either metabolic or respiratory, depending on whether the cause originates in the kidneys or the lungs.
Metabolic Causes: Metabolic acidosis can be triggered by uncontrolled diabetes (DKA), kidney failure, severe diarrhea (causing bicarbonate loss), or poisoning by substances like methanol.
Respiratory Causes: Respiratory acidosis is caused by impaired breathing, which prevents the lungs from expelling enough carbon dioxide. Common causes include COPD, neuromuscular disorders, and sedative overuse.
Diagnosis is Key: Blood tests, such as arterial blood gas (ABG) and metabolic panels, are used to diagnose acidosis and identify the specific cause.
Treatment Targets the Cause: Treatment for acidosis is focused on addressing the root problem, which may involve insulin for DKA, bicarbonate for kidney issues, or mechanical ventilation for severe respiratory failure.
Prevention is Possible: Maintaining hydration, managing underlying conditions like diabetes, and avoiding excessive alcohol consumption can help reduce the risk of developing certain types of acidosis.

The body's balancing act: How pH is regulated

To function properly, your body meticulously maintains a delicate balance of acids and bases, measured by the pH scale. A perfectly balanced pH of 7.0 is neutral, while values below indicate acidity and those above signify alkalinity. Your lungs and kidneys are the primary organs responsible for keeping your blood's pH stable, regulating it through the removal of excess acid and carbon dioxide. When this system is overwhelmed or impaired, acidosis can develop, categorized into either metabolic or respiratory, depending on the origin of the imbalance.

Metabolic acidosis: A closer look at internal production

Metabolic acidosis occurs when the body produces too much acid or when the kidneys are unable to remove sufficient amounts of acid. This can happen for a variety of reasons, leading to several distinct subtypes.

Causes of metabolic acidosis

Diabetic Ketoacidosis (DKA): In individuals with uncontrolled diabetes, particularly type 1, the body cannot use glucose for energy due to insufficient insulin. Instead, it begins to break down fat, which produces acidic ketones that build up in the blood.
Lactic Acidosis: This condition is caused by a buildup of lactic acid, which is produced by muscle cells and red blood cells when oxygen levels are low. Severe cases can be triggered by cancer, liver failure, excessive alcohol consumption, or prolonged strenuous exercise.
Kidney Disease: The kidneys play a critical role in filtering out excess acids. When kidney function declines due to chronic kidney disease (CKD) or kidney failure, these acids build up in the blood, leading to acidosis.
Severe Diarrhea: The intestines secrete a base called bicarbonate. Severe diarrhea causes a significant loss of this base, disrupting the acid-base balance and leading to hyperchloremic acidosis.
Toxin Ingestion: Ingesting certain toxic substances, such as antifreeze (ethylene glycol), methanol, or high doses of aspirin, can also cause a dangerous buildup of acid in the body.

Common symptoms of metabolic acidosis

Fatigue and weakness
Nausea and vomiting
Rapid, deep breathing (Kussmaul breathing) as the body attempts to expel carbon dioxide
Confusion or lethargy

Respiratory acidosis: When the lungs fail

Respiratory acidosis develops when the lungs cannot properly remove carbon dioxide (CO2) from the body. This leads to an increase of CO2 in the blood, which makes it more acidic. Impaired breathing is the root cause.

Causes of respiratory acidosis

Chronic Lung Diseases: Conditions like chronic obstructive pulmonary disease (COPD) and severe asthma can obstruct the airways, preventing adequate CO2 release.
Neuromuscular Disorders: Diseases such as myasthenia gravis or muscular dystrophy can weaken the chest muscles required for breathing.
Central Nervous System Depression: Overuse of sedatives, opioids, or alcohol can slow down breathing, leading to CO2 retention.
Chest Wall Abnormalities: Conditions like severe scoliosis can physically restrict lung movement and impair breathing.
Obesity Hypoventilation Syndrome: Excess weight can put pressure on the lungs, limiting their ability to expand fully and causing CO2 to build up.

Common symptoms of respiratory acidosis

Confusion and disorientation
Fatigue and sleepiness
Shortness of breath
Headache
Rapid or shallow breathing

Comparing metabolic and respiratory acidosis

The fundamental difference between the two types of acidosis lies in their origin—either a metabolic process or a respiratory one. Understanding this distinction is key for medical professionals to determine the correct treatment plan.


Feature	Metabolic Acidosis	Respiratory Acidosis
Primary Cause	Excess acid production or insufficient kidney function.	Poor lung function and CO2 retention.
Underlying Problem	Kidneys are unable to excrete acid or a significant loss of bicarbonate occurs.	Lungs are unable to expel sufficient CO2.
Compensatory Mechanism	Lungs compensate by increasing breathing rate and depth (Kussmaul breathing).	Kidneys compensate by increasing bicarbonate retention.
Common Causes	DKA, kidney failure, lactic acidosis, severe diarrhea, poisoning.	COPD, asthma, neuromuscular disorders, sedative overdose.

Diagnosis and treatment

Diagnosing the cause of acidosis begins with a blood test, specifically an arterial blood gas (ABG) test, which measures blood pH and carbon dioxide levels. Doctors also use blood electrolyte and ketone tests to pinpoint the metabolic cause. Treatment is always focused on addressing the underlying cause.

For metabolic acidosis caused by DKA, insulin and IV fluids are often administered to manage blood sugar and ketone levels.
In cases of kidney-related acidosis, sodium bicarbonate or sodium citrate may be prescribed to increase the body's base levels.
Respiratory acidosis treatments involve improving lung function through medication, breathing support, or, in severe cases, mechanical ventilation.

How to reduce your risk

While some inherited forms of acidosis are unavoidable, certain lifestyle changes can significantly lower your risk of developing metabolic acidosis.

Stay Hydrated: Drinking plenty of water helps your kidneys flush out excess acid.
Manage Diabetes: For those with diabetes, diligently monitoring and controlling blood sugar levels is the most effective way to prevent diabetic ketoacidosis.
Moderate Alcohol Intake: Excessive alcohol consumption is a known trigger for lactic acidosis.
Adopt a Kidney-Friendly Diet: Especially if you have chronic kidney disease, a diet rich in fruits and vegetables and low in animal protein can help manage acid levels.

For more information on kidney-related issues, including metabolic acidosis, visit the National Kidney Foundation.

Conclusion: Acidosis requires expert care

Acidosis is a serious condition that can result from a wide range of underlying health issues affecting the kidneys or lungs. Whether metabolic or respiratory in origin, the buildup of excess acid in the blood can have severe consequences if left untreated. By understanding the causes, recognizing the symptoms, and working closely with healthcare professionals, you can effectively manage underlying conditions and minimize the risk of developing this critical health imbalance.

Frequently Asked Questions

Acidosis is a medical condition where there is too much acid in the body's fluids. It is characterized by an abnormally low blood pH, below the normal range of 7.35 to 7.45.

Metabolic acidosis results from the body either producing too much acid or losing too much bicarbonate (a base). In contrast, respiratory acidosis occurs when the lungs fail to remove enough carbon dioxide, leading to a buildup of acid in the blood.

Yes, uncontrolled diabetes, particularly type 1, can lead to diabetic ketoacidosis (DKA). In this condition, the body produces high levels of acidic ketones as an alternative energy source, causing metabolic acidosis.

The kidneys are responsible for filtering and removing excess acids from the blood. In metabolic acidosis, kidney disease or failure can prevent this process, causing a dangerous buildup of acid.

Signs of respiratory acidosis can include confusion, fatigue, sleepiness, shortness of breath, and headaches. These symptoms arise because the lungs cannot adequately expel carbon dioxide.

Acidosis is primarily diagnosed with an arterial blood gas (ABG) test, which measures the pH and carbon dioxide levels in the blood. Other tests, such as a metabolic panel, can help identify the underlying cause.

While not all forms are preventable, managing underlying conditions like diabetes, maintaining proper hydration, and avoiding excessive alcohol consumption can significantly reduce the risk of developing certain types of acidosis.

Left untreated, severe acidosis can lead to serious complications, including shock, heart problems, kidney damage, bone disease, and, in extreme cases, coma or death.