What is the treatment for metabolic acidosis in children?

Treatment of Metabolic Acidosis in Children

The treatment of metabolic acidosis in children should focus on identifying and treating the underlying cause while providing supportive care to correct the acid-base imbalance, with specific interventions determined by the etiology and severity of acidosis. 1, 2

Diagnosis and Classification

• Metabolic acidosis is characterized by decreased serum bicarbonate levels and can be classified based on the anion gap calculation, which helps determine the underlying cause 3
• Normal anion gap acidosis (hyperchloremic) typically results from renal tubular disorders or gastrointestinal bicarbonate losses 3
• High anion gap acidosis commonly occurs in diabetic ketoacidosis (DKA), lactic acidosis, sepsis, hypoxia, and inborn errors of metabolism 3, 4

Treatment Approach Based on Etiology

Diabetic Ketoacidosis (DKA)

• For children with DKA and ketosis/ketoacidosis, treatment with subcutaneous or intravenous insulin should be initiated to rapidly correct hyperglycemia and metabolic derangement 1
• Once acidosis is resolved, metformin should be initiated while subcutaneous insulin therapy is continued 1
• Volume resuscitation should be provided cautiously, with 20-40 ml/kg of either 0.9% saline or 4.5% human albumin solution 1
• Bicarbonate therapy is generally not recommended in DKA as it has not been shown to improve resolution of acidosis or time to discharge 2
• Monitor for hyperchloremic metabolic acidosis, which can develop during treatment with normal saline and may slow recovery 5

Lactic Acidosis

• Treatment should focus on addressing the underlying cause (hypoxia, sepsis, tissue hypoperfusion) 2, 6
• Avoid routine use of sodium bicarbonate in lactic acidosis as it may worsen intracellular acidosis without improving outcomes 2, 6
• In severe cases with hemodynamic compromise, cautious administration of bicarbonate may be considered when pH < 7.1 7

Renal Tubular Acidosis

• For distal or proximal renal tubular acidosis, alkali therapy with sodium bicarbonate is indicated 2, 3
• Chronic kidney disease-associated acidosis should be treated when serum bicarbonate is consistently < 18 mmol/L 2

Inborn Errors of Metabolism

• For metabolic acidosis due to mitochondrial disorders or other inborn errors, specific dietary modifications and supportive care are needed 4
• During acute decompensation, aggressive management of acidosis and prevention of catabolism are essential 4

General Management Principles

Fluid Resuscitation

• In children with metabolic acidosis and shock, provide volume resuscitation with 20 ml/kg boluses of colloid or 0.9% saline 1
• For children in coma with shock, 4.5% albumin may be preferred 1
• Monitor response closely and repeat fluid boluses if needed, up to 40 ml/kg 1

Sodium Bicarbonate Administration

• For severe metabolic acidosis (pH < 7.1) in less urgent forms, sodium bicarbonate may be given at approximately 2-5 mEq/kg over 4-8 hours, depending on severity 7
• Bicarbonate therapy should be planned in a stepwise fashion as the response is not precisely predictable 7
• Avoid attempting full correction of low total CO2 content during the first 24 hours to prevent iatrogenic alkalosis 7
• Target achievement of total CO2 content of about 20 mEq/liter at the end of the first day 7

Monitoring During Treatment

• Closely monitor electrolytes, particularly potassium levels, as acidosis correction can cause hypokalemia 2
• In severe cases, monitor blood gases, plasma osmolarity, arterial blood lactate, hemodynamics, and cardiac rhythm 7
• For children with persistent shock despite 40 ml/kg fluid resuscitation, consider central venous pressure monitoring to guide further management 1

Special Considerations

• In children with metabolic acidosis and respiratory distress, assess for underlying metabolic acidosis (base deficit > 8 mmol/l) which may be accompanied by compensated shock 1
• For children with recurrent episodes of ketoacidosis, evaluate for psychological factors including insulin omission, which is the most common cause of recurrent DKA 1
• Prevention strategies for recurrent acidosis include education about ketone monitoring and 24-hour telephone availability for families 1

By identifying and addressing the underlying cause while providing appropriate supportive care, most cases of metabolic acidosis in children can be effectively managed with improved outcomes.