Pediatric emergency medicine trisk 2440 2440

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 do 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 1 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
1 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:
. 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 1 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,