Investigation

Investigations include:

• FBC - neutropaenia and thrombocytopaenia (high levels of organic acids cause bone marrow suppression)
• Biochemistry - hypoglycaemia may be present; check amylase if pancreatitis suspected
• ammonia - raised, can be >1000 micromol/L
• blood gas - primary metabolic acidosis, raised anion gap (usually >25 mmol/L); lactate may be raised but will only account for part of the anion gap increase
• urinary ketones - present
• carnitine - overall plasma levels decreased; proportion of esterified to non-esterified carnitine markedly increased
• plasma amino acids - increased glycine concentration
• urinary organic acids - will show a profile typical of the disorder

Reference

• 1) British Inherited Metabolic Diseases Group: www.bimdg.org.uk
• 2) A Clinical Guide To Inherited Metabolic Diseases, Third Edition, JTR Clarke, Cambridge University Press
• 3) Clinical Chemistry, Fourth Edition, William J Marshall, Mosby
• http://emedicine.medscape.com/article/948084-overview