What is Metabolic Acidosis? What are the types, causes & treatment?

Metabolic acidosis is a significant topic in medical and clinical practice, especially in critical care and nephrology. It can arise from various health conditions and requires timely recognition and appropriate management. Understanding its different types, the root cause, and knowing the available treatment strategies are essential for effective patient care. This blog concisely overviews metabolic acidosis, focusing on its classification, common triggers, and standard treatment regimen.

What is Metabolic acidosis?

Metabolic acidosis is a serious acid-base disturbance that occurs when the body produces too much of acid, loses too much of bicarbonate, or when the kidneys fail to excrete enough acid. It results in a low blood pH (<7.35) and reduced serum bicarbonate levels (<22 mEq/L). This condition indicates that the body is struggling to maintain its normal acid-base balance, which is critical for proper cellular functions and overall metabolic processes.

Metabolic acidosis is not a disease but rather a symptom of an underlying problem, and identifying the root cause is essential for effective treatment.

What are the categories of metabolic acidosis?

Metabolic acidosis is commonly categorised based on the Anion Gap (AG), which helps differentiate the cause:

1. High Anion Gap Metabolic Acidosis (HAGMA)

In HAGMA, an accumulation of acids that are normally present in the blood is not measured in routine blood tests, hence the increase in the gap.

Causes of HAGMA are: (Mnemonic: MUDPILES)

• Methanol

• Uremia (chronic kidney)

• Diabetic ketoacidosis

• Paraldehyde or propylene glycol

• Isoniazid or iron oversee

• Lactic acidosis

• Ethylene glycol

• Salicylates (aspirin overdose)

👉Also Read: Anemia: Causes, Symptoms, Types & Treatment Options

What are the key factors that cause metabolic acidosis?

1. Increased acid production

• Lactic acidosis: seen in conditions like sepsis, hypoperfusion, shock, or intensive exercise

• Ketoacidosis: in diabetes (DKA), alcohol use (AKA), or starvation stress

• Ingested toxins: Methanol, ethylene glycol, or aspirin can produce acidic metabolites

2. Loss of bicarbonate ions

• Gastrointestinal loss: chronic diarrhea, pancreatic fistula

• Renal loss: In renal tubular acidosis, bicarbonate reabsorption is impaired

3. Decreased renal acid excretion

• Chronic kidney disease reduces the kidneys’ ability to excrete hydrogen ions and regenerate bicarbonate.

• Obstructive uropathy or acute renal injury may contribute.

What are the major symptoms of metabolic acidosis?

Symptoms vary depending on the severity and underlying conditions, but some common symptoms are:

• Respiratory compensation: rapid and deep breathing as the body tries to blow off Carbon dioxide

• Neurological symptoms: confusion, drowsiness, lethargy, headache

• Gastrointestinal: Nausea, vomiting, abdominal pain

• Cardiovascular: hypotension, arrhythmias, shock

• Fatigue and weakness

• In severe cases, if not treated, it can lead to coma and death.

What is the Diagnostic approach?

Accurate diagnosis involves a combination of laboratory tests and clinical evaluations

1. Arterial Blood Gas (ABG)

• Confirms acidemia (pH:<7.35)

• Shows low bicarbonates

2. Anion Gap Calculation

• Normal AG: 8-12 mEq/L

• High AG indicates the accumulation of unmeasured acids

3. Serum Lactate and Ketones:

• Elevation in lactic acidosis and ketoacidosis, respectively

4. Renal function tests:

• Accelerated creatinine

5. Urine pH & Urinary Anion Gap

• Helps to identify the tubular cause

6. Toxicology screening poisoning is suspected of poisoning.

What are the common treatments?

1.Treat the underlying cause.

• In case of Diabetic ketoacidosis: Administer insulin, IV fluids, correct electrolytes

• Lactic acidosis: improve tissue perfusion, oxygenation, and treat sepsis

• Toxin ingestion: use antidotes, perform dialysis if needed

• Diarrhea: Rehydrate, and replace bicarbonates if severe

• Renal failure: may require dialysis

2.Restore Electrolyte balance

• Correct potassium, calcium, and magnesium imbalances

• Monitor fluid status closely

3. Monitor blood gases and pH

• Adjust treatment based on responses.

• Use serial ABGs for critical cases.

When to consider bicarbonate treatment?

Bicarbonate therapy is not always indicated and may sometimes worsen the outcome if misused. Consider IV sodium bicarbonate if:

• Severe acidemia (pH <7.1) causing cardiac dysfunction or arrhythmias

• Renal failure where bicarbonate regeneration is impaired

• Hyperkalemia coexisting with acidosis

Caution:

• Avoid in lactic acidosis unless pH is dangerously low

• Rapid correction may cause alkalosis, hypokalemia, or fluid overload

👉Also Read: ACE inhibitors (Angiotensin-Converting Enzyme Inhibitors)

What are the supportive and ongoing care?

Once stabilized, the focus shifts to preventing recurrence and long-term management.

• Manage chronic kidney disease, diabetes, or other causative conditions

• Regular monitoring of electrolytes and ABGs

• Educate patients about diet, hydration, and medication compliance

• For inherited or chronic causes (RTA), oral alkali therapy may be required long-term

Summary

Metabolic acidosis is a critical condition that reflects a disruption in the body’s acid-base equilibrium. Whether due to excess acid, loss of bicarbonate, or impaired renal function, it requires timely identification, accurate diagnosis, and targeted treatment. Understanding the underlying cause is essential to guide the therapy.

With appropriate interventions, most cases of metabolic acidosis are reversible, and treatment improves with early detection and management.

About the Author

Krupa Karamchand

Content Writer | Elite Expertise

Krupa Karamchand is a B. Pharm graduate and KAPS-qualified pharmacist with over 7 years of experience in the pharmaceutical field. As an experienced SEO content writer, she combines her in-depth healthcare knowledge with proven digital strategies to create informative, engaging, and search engine–optimized blogs. Krupa is passionate about making complex medical topics easy to understand and accessible to all readers.

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