Catastrophic Metabolic Encephalopathies in the Newborn Period: Evaluation and Management

The newborn who presents with neurologic symptoms such as seizures or lethargy due to inborn error of metabolism is an important problem. Although each inborn error that presents in this manner is rare, these conditions are not rare as a group, and more than one in 1000 babies is affected with one of the more than 100 different inborn errors that are now known. Many of these conditions present with much the same features seen in sepsis or asphyxia and, when untreated, can lead rapidly to death or permanent neurologic damage. Early diagnosis and management may prevent some or all of this morbidity, and also permits the parents to be informed about the changes of having other affected children. Despite the large number and complexity, most metabolic encephalopathies can be diagnosed by applying a few simple clinical principles and laboratory tests. These principles, and the typical features of some inborn errors that present in the neonate, are detailed in this article.