Metabolic Acidosis: Causes, Symptoms, Diagnosis, and Treatment

The body maintains a delicate acid-base balance to function properly. When this balance shifts and acid levels rise, it can lead to a condition known as metabolic acidosis. This occurs when the body either produces too much acid, cannot remove enough acid, or loses excessive bicarbonate — a base that helps neutralize acid in the blood.

If left untreated, metabolic acidosis can affect organ function, impair metabolism, and even become life-threatening. Understanding its causes, symptoms, and treatment is vital for early detection and effective management.

What Is Metabolic Acidosis?

Metabolic acidosis is a condition characterized by an excess of acid in the body’s fluids, leading to a decrease in blood pH below 7.35. Normally, the kidneys and lungs work together to maintain pH balance — the lungs remove carbon dioxide (an acid), and the kidneys excrete hydrogen ions while conserving bicarbonate.

When this balance is disrupted — due to kidney dysfunction, excessive acid production, or bicarbonate loss — metabolic acidosis develops.

Normal Blood pH and Acid-Base Balance

The normal blood pH range is 7.35 to 7.45.

• pH < 7.35: Indicates acidosis (too much acid or too little base).

• pH > 7.45: Indicates alkalosis (too much base or too little acid).

The body regulates pH through:

1. Buffer systems (like bicarbonate, phosphate, and proteins).

2. Respiratory system (exhaling CO₂).

3. Renal system (reabsorbing bicarbonate and excreting hydrogen ions).

When these mechanisms fail to maintain balance, metabolic acidosis can result.

Types of Metabolic Acidosis

Metabolic acidosis is broadly divided into four main types, depending on the underlying cause:

1. Diabetic Ketoacidosis (DKA)

• Common in people with diabetes, especially when insulin levels are low.

• The body breaks down fat instead of glucose, producing ketones, which are acidic.

• Leads to high anion gap acidosis.

Symptoms: Nausea, vomiting, fruity breath odor, rapid breathing, confusion.

2. Lactic Acidosis

• Occurs when lactic acid accumulates due to insufficient oxygen supply to tissues.

• Seen in shock, sepsis, heart failure, or strenuous exercise.

• Also associated with alcohol abuse, liver failure, or metformin use.

Symptoms: Weakness, muscle pain, rapid breathing, low blood pressure.

3. Renal (Kidney) Tubular Acidosis (RTA)

• The kidneys fail to excrete acids or reabsorb bicarbonate efficiently.

• Common in chronic kidney disease or genetic tubular disorders.

• Usually results in normal anion gap acidosis.

Symptoms: Fatigue, muscle weakness, bone pain, and kidney stones.

4. Hyperchloremic Acidosis

• Occurs when bicarbonate is lost and replaced by chloride.

• Common causes include severe diarrhea, vomiting, or renal issues.

• Also results in normal anion gap acidosis.

Symptoms: Dehydration, confusion, muscle cramps, irregular heartbeat.

Causes of Metabolic Acidosis

Metabolic acidosis can result from numerous underlying conditions and mechanisms:

1. Increased Acid Production

• Diabetic ketoacidosis

• Lactic acidosis

• Alcoholic ketoacidosis

• Starvation ketosis

• Toxin ingestion (e.g., methanol, ethylene glycol, salicylates)

2. Decreased Acid Excretion

• Chronic kidney disease

• Renal tubular acidosis

• Acute kidney injury

3. Bicarbonate Loss

• Severe diarrhea

• Pancreatic fistulas

• Intestinal suction or drainage

• Certain medications (e.g., acetazolamide)

4. Other Contributing Factors

• Shock or hypoxia

• Severe infection (sepsis)

• Dehydration

• Overuse of specific drugs or toxins

Symptoms of Metabolic Acidosis

Symptoms can vary depending on the severity and underlying cause but typically include:

• Rapid, deep breathing (Kussmaul respiration)

• Fatigue or weakness

• Headache and confusion

• Nausea and vomiting

• Loss of appetite

• Heart arrhythmias

• Low blood pressure

• Shock (in severe cases)

If untreated, metabolic acidosis can progress to coma or death, particularly in diabetic or renal patients.

Diagnosis of Metabolic Acidosis

At Sparsh Diagnostic Centre, metabolic acidosis is diagnosed through blood and urine tests that assess acid-base balance, kidney function, and possible causes.

1. Arterial Blood Gas (ABG) Test

• Measures pH, bicarbonate (HCO₃⁻), and partial pressure of carbon dioxide (PaCO₂).

• Confirms acidosis and determines its severity.

2. Serum Electrolytes

• Checks sodium, potassium, chloride, and bicarbonate levels.

3. Anion Gap Calculation

Used to identify the cause of metabolic acidosis.
Formula:
Anion Gap = (Na⁺ + K⁺) – (Cl⁻ + HCO₃⁻)

• Normal anion gap (8–12 mEq/L): Suggests bicarbonate loss or renal tubular acidosis.

• High anion gap: Indicates acid buildup (e.g., DKA, lactic acidosis).

4. Urinalysis

• Detects kidney function abnormalities or acid excretion issues.

5. Additional Tests

Depending on the suspected cause:

• Blood glucose (for DKA)

• Lactate levels (for lactic acidosis)

• Kidney function tests (BUN, creatinine)

• Toxicology screen (for poisoning)

Treatment of Metabolic Acidosis

The primary goal of treatment is to correct the underlying cause while restoring the body’s acid-base balance.

1. Treating the Underlying Cause

• Diabetic ketoacidosis: Administer insulin, fluids, and electrolytes.

• Lactic acidosis: Improve oxygen delivery, treat infection, and correct shock.

• Renal failure: Dialysis or bicarbonate therapy may be needed.

• Bicarbonate loss: Replace fluids and electrolytes orally or intravenously.

2. Bicarbonate Therapy

• Used in severe metabolic acidosis (pH < 7.1).

• Helps neutralize acid and stabilize pH temporarily.

• Must be used cautiously to prevent alkalosis or fluid overload.

3. Intravenous (IV) Fluids

• Rehydrate the body, restore electrolyte balance, and enhance renal function.

4. Dialysis

• Indicated for kidney failure or toxic ingestion (e.g., methanol, ethylene glycol).

• Removes acid and toxins from the bloodstream effectively.

5. Supportive Care

• Oxygen therapy (for hypoxia)

• Monitoring vital signs

• Nutritional support (especially in starvation or alcohol-related cases)

Complications of Metabolic Acidosis

If untreated, metabolic acidosis can lead to serious complications such as:

• Cardiac arrhythmias

• Shock or coma

• Bone demineralization

• Muscle breakdown

• Chronic kidney damage

• Respiratory failure

• Death (in severe untreated cases)

Early diagnosis and prompt management significantly improve outcomes.

Prevention of Metabolic Acidosis

While not all cases can be prevented, certain measures help reduce risk:

1. Manage diabetes effectively with regular insulin and glucose monitoring.

2. Avoid dehydration and maintain electrolyte balance.

3. Limit alcohol intake to prevent alcoholic ketoacidosis.

4. Avoid self-medication or exposure to toxins.

5. Monitor kidney function regularly if you have diabetes, hypertension, or chronic kidney disease.

6. Seek medical advice for persistent vomiting, diarrhea, or fatigue.

At Sparsh Diagnostic Centre, routine blood and urine tests can help detect acid-base imbalances early and guide appropriate treatment.

When to See a Doctor

You should seek immediate medical attention if you experience:

• Rapid, deep breathing

• Confusion or disorientation

• Persistent vomiting or diarrhea

• Severe fatigue or weakness

• Uncontrolled blood sugar levels

Prompt evaluation is essential, especially for individuals with diabetes, kidney disease, or heart conditions.

Prognosis

The prognosis of metabolic acidosis depends on:

• The underlying cause

• Severity of acid imbalance

• How quickly treatment begins

Most patients recover well with early diagnosis and targeted treatment. However, delayed intervention can result in organ failure or death.

Metabolic Acidosis vs. Respiratory Acidosis

FAQ Section

1. What is the main cause of metabolic acidosis?

Metabolic acidosis occurs when the body produces too much acid or cannot remove it effectively, often due to diabetes, kidney disease, or severe diarrhea.

2. Can metabolic acidosis be reversed?

Yes. Once the underlying cause (like DKA, kidney dysfunction, or dehydration) is treated, the acid-base balance can usually be restored.

3. How is metabolic acidosis diagnosed?

It’s diagnosed through arterial blood gas analysis, electrolyte tests, and anion gap calculation to identify the source of acid imbalance.

4. What is the difference between high and normal anion gap acidosis?

• High anion gap: Caused by acid buildup (e.g., DKA, lactic acidosis).

• Normal anion gap: Caused by bicarbonate loss (e.g., diarrhea, RTA).

5. Can metabolic acidosis cause death?

Yes, severe untreated metabolic acidosis can lead to organ failure, cardiac arrest, or death, especially in diabetics or patients with kidney disease.

6. How is lactic acidosis treated?

Treatment involves improving oxygenation, correcting the cause (like infection or shock), and managing underlying metabolic disorders.

7. Does diet play a role in preventing metabolic acidosis?

Yes. A balanced diet rich in fruits, vegetables, and adequate hydration supports kidney function and helps maintain acid-base balance.

Metabolic acidosis is a serious condition that requires prompt medical attention. By understanding its causes and recognizing symptoms early, patients can seek timely diagnosis and treatment — preventing severe complications.

At Sparsh Diagnostic Centre, we offer advanced diagnostic services, including blood gas analysis, kidney function tests, and electrolyte panels, to detect and manage acid-base disorders effectively.

If you or a loved one experiences symptoms like rapid breathing, confusion, or persistent fatigue, visit Sparsh Diagnostic Centre, Kolkata for expert evaluation and care.

#BhaloTheko