Lactic Acidosis

Initial Workup

• Increased lactate
• → Urine organic acids, plasma acylcarnitine profile

Abnormal or Diagnostic Profile

• • Hypoglycemia, "Reye-like" syndrome → Fatty acid oxidation defects
• • Metabolic acidosis → Propionic acidemia, Methylmalonic acidemia, Other organic aciduria
• • Skin rash/alopecia → Biotinidase, Holocarboxylase synthetase deficiency

Normal or Nonspecific Findings — Increased pyruvate, Normal lactate/pyruvate ratio

• • Hypoglycemia +/- Ketones → Glycogen storage disease type 1, Fructose 1,6-diphosphatase, Phosphoenolpyruvate carboxykinase
• • Hyperglycemia → Diabetes mellitus
• • Normal glycemia, No ketosis → Pyruvate dehydrogenase complex

Normal or Nonspecific Findings — Decreased or normal pyruvate, Increased lactate/pyruvate ratio

• • Normal O2 saturation → Multisystem involvement, "ragged red fiber" in muscle biopsy: - Increased 3 Hydroxy butyrate:acetoacetate → Respiratory chain mitochondrial defects
• • Normal to low 3 Hydroxy butyrate:acetoacetate → Pyruvate carboxylase
• • Decreased O2 saturation → Tissue hypoxia