Approach to Management of Inborn Errors of Metabolism

Abstract

This article reviewed the pathophysiology, diagnostic approach based on age of presentation and symptom complex, neonatal screening strategies, methods of obtaining and handling of samples and management of metabolic emergencies while awaiting results of investigations. The principles of long-term therapy, prevention and future prospects of IEM
were also discussed. Inborn errors of metabolism (IEM) must be considered in the differential diagnosis of critically ill neonates and infants with severe hypoglycaemia, encephalopathy, acidaemia, conjugated hyperbilirubinaemia or hyperammonaemia for which there is no apparent cause after a conventional work-up. Investigation is initiated by screening tests which includes blood glucose, ammonia, amino acids, urea and electrolytes levels, liver function tests and blood gases. Urinalysis for ketones, reducing substances, amino acids and organic acids is a very useful diagnostic tool. In neonates, ketonuria with acidosis is a very important laboratory finding pointing to IEM. Although the prognosis for patients with IEM presenting in the neonatal and early infancy period is often poor, every effort must be made to establish the diagnosis for parental counselling and in case prenatal diagnosis is possible in future

pregnancies. In conclusion, when presented with an ill full-term neonate, pursue the usual bacterial septicaemia work-up but do not neglect evaluation for metabolic disease.

Keywords: Inborn errors, hereditary metabolic disorders, neonatal screening.