Affiliations: Mitochondrial Research Group, Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne, UK | Newcastle upon Tyne Hospitals NHS Trust, Newcastle upon Tyne, UK
Note:  Corresponding author: Dr Victoria Nesbitt, Mitochondrial Research Group, The Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK. Tel.: +44 191 2223007; Fax: +44 191 2824373; E-mail: V.Nesbitt@ncl.ac.uk
Abstract: Congenital lactic acidosis presents in the newborn period, usually in a symptomatic infant (hypotonia, weakness, respiratory failure), and has a poor prognosis. The underlying aetiology may be an inborn error of metabolism, including Lethal Infantile Mitochondrial Disease (LIMD). In LIMD, lactic acidosis arises because poorly functioning mitochondria do not allow oxidation of pyruvate, which in turn leads to an accumulation of lactate as a by-product of anaerobic metabolism. Lactic acidosis may be the first clue to an underlying mitochondrial disease. In this article we will review the physiology of lactate metabolism, highlight clinical features associated with congenital lactic acidosis, and explore management options in order to make a diagnosis of mitochondrial disease.