Differential Diagnosis for 1-year old with Developmental Delay, Hypotonia, and Lactic Acidosis
Single Most Likely Diagnosis
- Pyruvate Dehydrogenase Complex (PDH) Deficiency: This is a common cause of lactic acidosis and developmental delay in infants. PDH deficiency leads to impaired conversion of pyruvate to acetyl-CoA, resulting in lactic acidosis and energy deficits that can cause hypotonia and developmental delays.
Other Likely Diagnoses
- Krebs Cycle Disorders: Deficiencies in enzymes involved in the Krebs cycle (e.g., citrate synthase, aconitase, isocitrate dehydrogenase) can lead to impaired energy production, resulting in lactic acidosis, hypotonia, and developmental delays.
- Fatty Acid Oxidation Disorders: Disorders such as very-long-chain acyl-CoA dehydrogenase (VLCAD) deficiency or carnitine palmitoyltransferase II (CPT II) deficiency can cause lactic acidosis, hypotonia, and developmental delays due to impaired fatty acid oxidation.
- Mitochondrial Respiratory Chain Complex Deficiencies: Deficiencies in complexes I, II, III, or IV of the mitochondrial respiratory chain can lead to impaired energy production, resulting in lactic acidosis, hypotonia, and developmental delays.
Do Not Miss Diagnoses
- Leigh Syndrome: A severe mitochondrial disorder that can present with lactic acidosis, hypotonia, and developmental delays. It is essential to consider this diagnosis due to its poor prognosis and potential for rapid progression.
- Methylmalonic Acidemia: A disorder of organic acid metabolism that can cause lactic acidosis, hypotonia, and developmental delays. Prompt diagnosis and treatment are crucial to prevent long-term complications.
Rare Diagnoses
- Dihydrolipoamide Dehydrogenase (DLD) Deficiency: A rare disorder that affects the conversion of pyruvate to acetyl-CoA, leading to lactic acidosis, hypotonia, and developmental delays.
- Pyruvate Carboxylase Deficiency: A rare disorder that impairs the conversion of pyruvate to oxaloacetate, resulting in lactic acidosis, hypotonia, and developmental delays.
- Phosphoenolpyruvate Carboxykinase (PEPCK) Deficiency: A rare disorder that affects gluconeogenesis, leading to lactic acidosis, hypotonia, and developmental delays.