[The plasma anion gap is a useful tool for evaluating children with metabolic acidosis]

Area of Science:

• Pediatric Nephrology
• Pediatric Critical Care Medicine
• Clinical Chemistry

Background:

• Metabolic acidosis is a common clinical problem in hospitalized children.
• Identifying the underlying cause is crucial for appropriate management.
• The plasma anion gap is a key diagnostic parameter when the etiology is not immediately clear.

Observation:

• This case report presents two pediatric patients with unexplained metabolic acidosis.
• One patient presented with normal anion gap metabolic acidosis.
• The second patient exhibited increased anion gap metabolic acidosis.

Findings:

• The patient with normal anion gap metabolic acidosis was diagnosed with renal tubular acidosis.
• The patient with increased anion gap metabolic acidosis was found to have D-lactic acidosis.
• These findings highlight distinct etiologies for metabolic acidosis in children.

Implications:

• Accurate diagnosis of metabolic acidosis subtypes is essential for targeted treatment in pediatric patients.
• The plasma anion gap remains a valuable tool in the etiological workup of pediatric metabolic acidosis.
• This case series underscores the importance of considering diverse causes, including D-lactic acidosis and renal tubular acidosis, in pediatric metabolic acidosis evaluation.