Causes of Metabolic Acidosis and Its Effect on Kidney Function

Metabolic acidosis is a condition that occurs when there is too much acid in the body fluids. It develops when the body either produces excessive acid, cannot remove enough acid or loses too much bicarbonate (a base that helps neutralise acid). The kidneys' role is to maintain the body’s acid–base balance, which is essential. When this balance is disturbed, it can affect kidney function and overall health.

Getting to know what causes metabolic acidosis and how it influences your kidneys can feel a bit technical. But once you break it down, it’s really about knowing the meaning of metabolic acidosis, how your body keeps its internal chemistry in balance, especially if you’re living with chronic kidney disease (CKD), diabetes or other metabolic conditions.

What is Metabolic Acidosis?

Metabolic acidosis is a disorder characterised by a decrease in blood pH due to an accumulation of acid or a loss of bicarbonate. Normally, the body maintains blood pH within a narrow range of approximately 7.35 to 7.45. When the pH falls below this range due to metabolic factors, acidosis occurs.

How does metabolic acidosis occur?

The kidneys and lungs work together to regulate acid levels. The lungs remove carbon dioxide through breathing, while the kidneys remove hydrogen ions and regenerate bicarbonate.

According to the National Kidney Foundation, metabolic acidosis is commonly seen in people with chronic kidney disease because damaged kidneys cannot remove enough acid from the blood. The Cleveland Clinic also notes that this condition can arise from several metabolic disturbances and underlying illnesses.

Primary Causes of Metabolic Acidosis

Metabolic acidosis can be caused by various medical conditions and metabolic imbalances.

So, what is the most common cause of metabolic acidosis? The most common causes of metabolic acidosis include:

1. Chronic Kidney Disease (CKD)

In CKD, due to the reduced kidney function, acid removal is affected, leading to acid buildup in the bloodstream.

2. Diabetic Ketoacidosis (DKA)

In people with mismanaged diabetes, especially diabetes type-1, the body breaks down fat for energy due to insufficient insulin. In this process, there are ketones produced, which are acidic. When ketone levels rise, diabetic ketoacidosis occurs.

3. Severe Diarrhoea

Prolonged diarrhoea can cause loss of bicarbonate from the digestive tract and without enough bicarbonate to neutralise acids, it can cause metabolic acidosis.

4. Lactic Acidosis

Lactic acidosis occurs when lactic acid builds up in the body. It can be caused by severe infection, shock, heart failure or intense exercise in certain rare situations.

5. Poisoning or Toxin Exposure

Ingestion of methanol, antifreeze or high doses of certain medications can cause metabolic acidosis.

6. Renal Tubular Acidosis

It is when the kidneys fail to properly excrete acids into the urine, even if kidney function appears somewhat preserved.

Each of these causes can disrupt your body’s acid–base balance through different mechanisms but the result is a decrease in blood pH. While these conditions can lead to acid buildup, the main cause of metabolic acidosis worldwide is kidney dysfunction.

How Metabolic Acidosis Affects Kidney Function?

Metabolic acidosis causes kidney problems and also worsens kidney function over time. For someone with CKD, persistent acidosis can:

• It can lead to the progression of kidney damage
• Increase inflammation within the kidney tissues
• Cause muscle breakdown
• Affects bone health by drawing calcium from bones

When acid levels are elevated, the kidneys have to work harder to compensate. This can, over time, strain and contribute to further loss of kidney function. The studies cited by kidney health organisations show that correcting metabolic acidosis in CKD patients may help slow the progression of kidney disease.

Symptoms and Diagnosis of Metabolic Acidosis

Symptoms can vary depending on the severity and underlying cause. Mild metabolic acidosis may produce few noticeable signs, while severe cases can become life-threatening. In emergency settings, severe metabolic acidosis causes rapid deterioration if not treated promptly. Common symptoms include:

• Rapid breathing (as the body attempts to expel carbon dioxide)
• Fatigue and weakness
• Confusion or drowsiness
• Headache
• Nausea and vomiting
• Loss of appetite

In more severe cases, symptoms may include irregular heartbeat, low blood pressure or shock.

Diagnosis

Metabolic acidosis is diagnosed through laboratory tests, including:

• Arterial blood gas (ABG) analysis to measure blood pH and bicarbonate levels.
• Serum electrolyte tests to evaluate bicarbonate concentration and calculate the anion gap.
• Kidney function tests, such as serum creatinine and estimated glomerular filtration rate.

Doctors may also investigate underlying causes through additional blood, urine or imaging tests.

Treatment Options for Metabolic Acidosis

How to treat metabolic acidosis depends on the underlying cause and severity.

1. Treating the Underlying Condition

For instance, if diabetes is the cause, insulin therapy is required. In cases of infection or shock, you should seek appropriate medical management.

2. Bicarbonate Therapy

In some patients, especially those with CKD, oral sodium bicarbonate may be prescribed to help neutralise the acid.

3. Intravenous Fluids

Severe acidosis may require IV fluids and electrolytes to stabilise the patient.

4. Dialysis

Dialysis is needed to remove excess acids from the blood, especially in advanced kidney failure or toxin-related acidosis.

Prompt treatment is important because untreated metabolic acidosis can lead to organ dysfunction.

Lifestyle and Dietary Adjustments for Metabolic Acidosis

For individuals at risk, learning how to manage metabolic acidosis should be your first step. Especially those with chronic kidney disease, lifestyle measures can help manage acid levels:

• Following a balanced diet that includes fruits and vegetables (as advised by a healthcare provider)
• Limiting the excessive intake of animal protein is recommended
• Managing diabetes through medication and diet carefully to prevent ketoacidosis
• Staying hydrated
• Regular monitoring of kidney function

Conclusion

The cause of metabolic acidosis is excessive acid buildup in the body due to impaired acid elimination, excessive acid production or bicarbonate loss. If left untreated, metabolic acidosis can worsen kidney function and contribute to muscle loss, bone problems and cardiovascular risks. Including management of the underlying cause and correction of bicarbonate levels is essential to prevent complications.

You don’t have to manage kidney complications alone. For trusted dialysis and kidney care support, book an appointment with NephroPlus. 

FAQs

How does metabolic acidosis affect the body?

Metabolic acidosis lowers blood pH, which can disrupt normal cell function. It may cause rapid breathing, fatigue, confusion, muscle breakdown and bone loss. Severe cases can impair organ function.

Can metabolic acidosis cure itself with time?

In mild cases, metabolic acidosis may improve once the underlying cause is treated. However, chronic kidney conditions require medical management. It does not resolve on its own without addressing the cause.

Is there a link between acidosis and diabetes?

Yes, uncontrolled diabetes, particularly type 1 diabetes, can lead to diabetic ketoacidosis, a type of metabolic acidosis caused by high levels of ketones.

How is metabolic acidosis diagnosed?

It is diagnosed through blood tests such as arterial blood gas analysis, electrolyte testing and kidney function tests. These help determine blood pH, bicarbonate levels and underlying causes.

Are certain populations at higher risk for metabolic acidosis?

Yes, people with kidney diseases, diabetes that has not been managed, prolonged diarrhoea or exposure to toxins are at higher risk.