Etiology of the Neonatal Hypoglycemias.

To provide a more appropriate foundation for dealing with the problem of hypoglycemia in newborn infants, this article focuses on the mechanisms which underlie the various forms of neonatal hypoglycemia and discusses their implications for newborn care. Evidence indicates that all of the major forms of neonatal hypoglycemia are the result of hyperinsulinism due to dysregulation of pancreatic islet insulin secretion. Based on these observations, the authors propose that routine measurement of B-hydroxybutyrate should be considered an essential part of glucose monitoring in newborn infants.

Role of beta-hydroxybutyrate measurement in the evaluation of plasma glucose concentrations in newborn infants.

OBJECTIVE: The Glucose in Well Babies (GLOW) Study showed that there are two phases of low glucose concentrations in healthy newborn infants: an initial phase in which plasma concentrations of ketones are low; and a second phase in which low glucose concentrations are accompanied by elevated concentrations of ketones. The implications of these two phases for the brain differ depending on whether ketones are available as alternative substrate for brain metabolism. The purpose of this study was to estimate the duration of these two phases of neonatal low glucose concentrations in 66 healthy breastfed newborns from the GLOW Study during the first 5 days of life. METHODS: The sum of glucose and beta-hydroxybutyrate (BOHB) was used as a proxy for the total concentrations of insulin-dependent fuels for the brain; a threshold value below 4 mmol/L was taken to indicate the presence of relative hyperinsulinism and a BOHB concentration above 0.5 mmol/L to indicate ketonaemia. RESULTS: The first phase of low glucose concentrations lasted a median of 40 hours and in 15% of infants, this persisted beyond 60 hours. Fifty (76%) of the 66 infants subsequently had ketonaemia, which resolved at a median age of 76 hours (range 41->120 hours). CONCLUSIONS: These data suggest that monitoring BOHB concentrations may be useful for interpreting glucose concentrations in newborns and screening for persistent hyperinsulinism.

Hiperinsulinismo na infância: quando apenas uma dosagem de insulina não é suficiente / Hyperinsulinism in infancy and childhood: when an insulin level is not always enough

INTRODUÇÃO: A hipoglicemia em bebês e crianças pode causar convulsões, atraso de desenvolvimento e dano cerebral permanente. O hiperinsulinismo (HI) é a causa mais comum de hipoglicemia, seja transitória ou permanente. A HI é caracterizada pela secreção inadequada de insulina, o que resulta em hipoglicemia persistente, de leve a grave. As diferentes formas de HI representam um grupo de doenças clínica, genética e morfologicamente heterogêneo. CONTEÚDO: Hiperinsulinismo congênito está associado às mutações de SUR-1 e Kir6.2, glucoquinase, glutamato desidrogenase, 3-hidroxiacil-CoA desidrogenase de cadeia curta e expressão ectópica de SLC16A1 na membrana plasmática das células beta. O HI pode estar associado ao estresse perinatal, como asfixia do nascimento, toxemia materna, prematuridade ou retardo do crescimento intra-uterino, resultando em hipoglicemia neonatal prolongada. Mimetismo de HI neonatal inclui pan-hipopituitarismo, hipoglicemia induzida por fármaco, insulinoma, anticorpos antiinsulina e estimuladores do receptor de insulina, síndrome de Beckwith-Wiedemann e distúrbios congênitos de glicosilação. Exames laboratoriais para HI podem incluir quantificação de glicose, insulina, β-hidroxibutirato, ácidos graxos, amônia e perfil de acilcarnitinas plasmáticos, além de ácidos orgânicos urinários. Os exames genéticos estão disponíveis em laboratórios comerciais para os genes sabidamente associados à hiperinsulinemia. Testes de resposta insulínica aguda (RIA) são úteis na caracterização fenotípica. Exames de imagem e histológicos também estão disponíveis para diagnosticar e classificar o HI. O objetivo do tratamento de crianças com HI é prevenir os danos cerebrais da hipoglicemia, mantendo níveis de glicose plasmática acima de 70mg/dl por terapia farmacológica ou cirúrgica. CONCLUSÃO:A terapêutica do HI requer abordagem multidisciplinar que inclui endocrinologistas pediátricos, radiologistas, cirurgiões e patologistas, os quais são treinados para diagnosticar..

BACKGROUND: Hypoglycemia in infants and children can lead to seizures, developmental delay, and permanent brain damage. Hyperinsulinism (HI) is the most common cause of both transient and permanent disorders of hypoglycemia. HI is characterized by dysregulated insulin secretion, which results in persistent mild to severe hypoglycemia. The various forms of HI represent a group of clinically, genetically, and morphologically heterogeneous disorders. CONTENT: Congenital hyperinsulinism is associated with mutations of SUR-1 and Kir6.2, glucokinase, glutamate dehydrogenase, short-chain 3-hydroxyacyl-CoA dehydrogenase, and ectopic expression of SLC16A1 on β-cell plasma membrane. Hyperinsulinism may be associated with perinatal stress such as birth asphyxia, maternal toxemia, prematurity or intrauterine growth retardation, resulting in prolonged neonatal hypoglycemia. Mimickers of hyperinsulinism include neonatal panhypopituitarism, drug-induced hypoglycemia, insulinoma, antiinsulin and insulin-receptor stimulating antibodies, Beckwith-Wiedemann Syndrome, and congenital glycosylation disorders. Laboratory testing for hyperinsulinism may include quantification of blood glucose, plasma insulin, plasma β-hydroxybutyrate, plasma fatty acids, plasma ammonia, plasma acylcarnitine profile and urine organic acids. Genetic testing is available at commercial laboratories for genes known to be associated with hyperinsulinism. Acute insulin response (AIR) tests are useful in phenotypic characterization. Imaging and histological tools are also available to diagnose and classify hyperinsulinism. The goal of treatment in infants with hyperinsulinism is to prevent brain damage from hypoglycemia by maintaining plasma glucose levels above 700 mg/l (70 mg/dl) through pharmacologic or surgical therapy. SUMMARY: The treatment of hyperinsulinism requires a multidisciplinary approach that includes pediatric endocrinologists, radiologists, surgeons, and pathologists who trained to diagnose...