Pediatrics--Metabolism ====================== þ Hypoglycemia - In children, infants, and term neonates older than 1 to 2 days of life, hypoglycemia is usually defined asa serum glucose concentration less than 40 to 45 mg/dL. - In term and premature neonates within 1 day of life, levels as low as 30 mg/dL are considered by some to be normal. The laboratory value should be interpreted in the context of the clinical presentation, because symptoms may occur within a continuum of low glucose levels. Glucose levels of 50 to 60 mg/dL with symptoms of hypoglycemia may warrant treatment. - Important etiologies in the emergency department include infection, adrenal insufficiency, inborn errors, and medication induced causes. Hyperinsulinemia, particularly persistent hyperinsulinemic hypoglycemia of infancy, should be considered as a potential cause of intractable hypoglycemia from the newborn period to 6 months of age. - The normal glucose requirement in a neonate is 6 to 10 mg/kg/min, which is roughly equivalent to an infusion of 10% dextrose-containing solution at 1.5 times the maintenance rate. - If hypoglycemia persists despite boluses and infusions, a hyperinsulinemic state should be considered. Glucagon, 0.1 to 0.2 mg/kg (up to 1 mg) parenterally, can be given to infants for refractory hypoglycemia. - Hydrocortisone, 2 to 3 mg/kg or 25 to 50 mg/m2, can also be considered for refractory hypoglycemia [Kwon KT, Tsai VW. Metabolic emergencies. Emergency medicine clinics of North America 2007;25:1041-60, vi.] þ Hyperglycemia/DKA - Hyperglycemia is typically defined as a glucose concentration of greater than 125 to 150 mg/dL. It is often seen in critically ill, non-diabetic patients of all ages and can signify increased mortality. Hyperglycemia is frequently seen in the first week of life and is inversely correlated to gestational age, with up to 18 times greater occurrence in neonates with birth weights less than 1000 g. It is also seen in infants who are acutely stressed or septic, receiving high rates of glucose infusion, or being treated with corticosteroids or other drugs. It is unknown whether infants with stress- induced hyperglycemia are at risk for later development of diabetes mellitus - DKA can be categorized as mild with a venous pH of 7.2 to 7.3, moderate with a venous pH of 7.1 to 7.2, and severe with a venous pH less than 7.1. - Isotonic solutions of 0.9% saline or Ringer’s lactate can be used with a volume of 10 to 20 mL/kg over 1 to 2 hours. The first 4 to 6 hours of replacing fluid deficit can be done with 0.9% normal saline or Ringer’s lactate. - Insulin bolus is not recommended in the pediatric population, because extensive evidence demonstrates this may exacerbate the risk of cerebral edema by dropping blood glucose levels too quickly. The dose of insulin should be 0.1 U/kg/h (or as low as 0.05 U/kg/h in some infants) with the rate of infusion adjusted to achieveInsulin bolus is not recommended in the pediatric population, because extensive evidence demonstrates this may exacerbate the risk of cerebral edema by dropping blood glucose levels too quickly. The dose of insulin should be 0.1 U/kg/h (or as low as 0.05 U/kg/h in some infants) with the rate of infusion adjusted to achieve a fall in blood glucose of about 50 to 90 mg/dL per hour. Once the blood glucose level falls to about 300 mg/dL, glucose should be added to the intravenous solution. As long as acidosis is present, insulin infusion should continue with the amount of added glucose adjusted to maintain levels between 150 and 200 mg/dL. - If the potassium level is greater than 4 mEq/L, 40 mEq/L of potassium is added to the intravenous fluids after vascular competency and urine output are restored. If the initial potassium level is less than 4 mEq/L, replacement should be started after the fluid bolus and before insulin therapy. Should laboratory values be delayed, the electrocardiogram and cardiac monitor can serve as a way to estimate potassium levels. Potassium phosphate combined with potassium chloride or acetate can be used with the maximum infusion rate at 0.5 mEq/kg/h. - The American Diabetic Association recommends consideration of bicarbonate in the pediatric patient if the pH remains less than 7.0 after the first hour of hydration [16]. If given for DKA, bicarbonate can be mixed as an isotonic solution (2 ampules of sodium bicarbonate in 0.45% normal saline) and given over 1 hour. - These treatment guidelines have been based on concerns of how to best avoid the development or worsening of cerebral edema. ... One should not infuse more than 50 mL/kg over the first 4 hours of treatment because higher volumes have been associated with an increased risk of cerebral edema. ... Treating cerebral edema has been attempted with mannitol (0.25–1.0 g/kg) or hypertonic saline (3%) given 5 to 10 mL/kg over a period of 30 minutes. [Kwon KT, Tsai VW. Metabolic emergencies. Emergency medicine clinics of North America 2007;25:1041-60, vi.] þ Galactosemia - screening done at birth in most states - lactose broken into galactose and glucose; inborn error of galactose metabolism causes it to build up. - affects brain, kidneys, liver, eyes - less severe in those of African descent. - presentation/diagnosis: + usually in infancy, sometimes diagnosis delayed by months or even years. + severe cases: vomiting, diarrhea, jaundice; sometimes, seizures or coma. + less severe: failure to thrive, vomiting that gets better when switched to Pedialyte or Koolaid. + physical findings: jaundice, cataracts, pallor + lab: hemolytic anemia, LFT elevations, hyperchloremic metabolic acidosis + definitive ED diagnosis: positive reducing substance test (e.g., Clinitest) and negative glucose oxidase (e.g., dextrostick). - ED treatment: + remove galactose from diet (e.g., switch to Pedialyte) + refer to metabolic disease specialist.