acids and acylcarnitines evaluation, and urine for organic acids, acylglycines, and orotic acid evaluation Liver dysfunction due to causes other than IEM, including primary liver disease, hepatic infection, toxic insult, sepsis, and asphyxia, may also cause hyperammonemia Imaging studies In the ED, imaging studies may be useful to guide management of potential acutely life-threatening organ system failure, particularly cerebral edema, hemorrhagic or thrombotic stroke, or cardiac failure Imaging studies to aid in diagnosis and long-term management are rarely appropriate in the ED setting Management Initial treatment of IEMs is aimed at correcting acute metabolic abnormalities with an empiric focus on preventing further catabolism Even the apparently stable patient may deteriorate rapidly For patients with IEMs of amino acid or carbohydrate metabolism, treatment is aimed at elimination of toxic metabolites For disorders of fatty acid oxidation or gluconeogenesis and glycogenolysis, therapy is aimed at correcting the energy deficiency In patients with lysosomal, mitochondrial, and peroxisomal disorders, emergent treatment is aimed at ameliorating the effects of organ dysfunction and usually involves temporizing measures that not have long-term impact on the inevitable progressive, degenerative course of these disorders As always, airway, breathing, and circulation must be addressed first Treatment for a potential IEM should be started empirically as soon as the diagnosis is considered ( Table 95.7 ) All oral intake should be stopped to prevent the introduction of potentially harmful protein or sugars Fluid bolus(es), as clinically indicated, should be normal saline, 10 mL/kg for neonates or patients with concern of heart failure and 20 mL/kg for infants and children Ringer lactate should be avoided because it can worsen acidosis The initial fluid bolus should be followed by dextrose-containing (typically at a dextrose concentration of at least 10%) IV fluids typically administered at 1.5 times maintenance rate to prevent catabolism Hypoglycemia Hypoglycemia, if present, should be corrected by dextrose bolus instead of adding D10 to bolus fluid; 0.25 to g/kg as 10% dextrose for neonates, and 10% or 25% dextrose for those beyond the neonatal period Hydration after fluid/dextrose bolus should be with D10 to D15 in ½ normal saline at to 1.5 times maintenance to maintain serum glucose level at 120 to 170 mg/dL, with the goal of preventing catabolism Large, rapid fluctuations in glucose level should be avoided Correction of hypoglycemia with glucose will improve most conditions with the exception of primary lactic acidosis due to disorders of gluconeogenesis involving pyruvate metabolism Acidosis Sodium bicarbonate may be used in some limited circumstances for the immediate treatment of metabolic acidosis, however, is likely to have minimal impact if the underlying metabolic cause is not treated Rapid and/or overcorrection of acidosis may have adverse CNS effects In the patient with hyperammonemia, alkalization of the blood favors the conversion of NH4 + to NH3 , which crosses the blood–brain barrier more readily and may cause cerebral edema and/or hemorrhage Furthermore, alkalization of the urine decreases excretion of ammonia Ultimately, definitive treatment of acidosis requires removal of the abnormal metabolites either by restricting dietary intake, or in severe cases, by dialysis, preferably hemodialysis Hyperammonemia Significant hyperammonemia is life threatening and must be treated immediately Treatment protocols for hyperammonemia in neonates and infants and children are detailed on the New England Consortium website and as per their site are meant to be used in consultation with an IEM specialist: https://newenglandconsortium.org/for-professionals/acute-illness-protocols/urea-cycledisorders/neonate-infant-child-with-hyperammonemia/ The goals of emergent treatment of hyperammonemia are to eliminate protein intake, prevent catabolism, and enhance the elimination of ammonia Central venous access is required for treatment Fluid containing 10% to 20% dextrose at a rate of to 1.5 times maintenance to maintain serum glucose level at 120 to 170 mg/dL should be administered to prevent catabolism and enhance elimination of ammonia If hyperglycemia occurs,