Acute illness in patients with Inborn Errors of Metabolism (< 18 years)

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Acute illness in patients with Inborn Errors of Metabolism (< 18 years)

Ammanul information

  • If Ammonul started, stop other ammonia scavengers
  • OK to give via peripheral line, central line preferred if available

Ammonia > 200 and mental status changes?

Plus appropriate electrolytes at 1.5x maintenance

D10 1/4 NS infusion

Central line?

Consider workup for specific signs of infection

Ammonia elevated?

Ammonia > 100?

Repeat ammonia Q6 hours

Ammonia, Serum

Organic acid disorder?

Maple syrup urine disease patients are at risk of hyponatremia induced cerebral edema and should be closely monitored in situations of dehydration.

Discuss need for admission with genetics/metabolic physician

Fatty acid oxidation disorder?

Glucose by Meter, POC
Creatine Phosphokinase (CPK), Serum
Inclusion Criteria
  • History of inborn error in metabolism
Exclusion Criteria
  • Concern for acute illness or altered mental status
  • Urea Cycle Disorders after liver transplant
  • Well appearing with no signs of acute illness

Consult Genetics/Metabolism Physician

< 2 months?

NS Bolus
NS infusion

Discuss need for Ammonul with genetics/metabolic physician, admit

Urea cycle disorder?

Signs of sepsis?

Complete Blood Count, Serum
Blood Culture (Aerobic and Anaerobic), Serum
Ceftriaxone injection
Admit to Floor
Admit to ICU
Vancomycin injection

Repeat ammonia, serum Q2 hours

Ammonia, Serum

Call genetics for dosage of Ammonul (sodium phenylacetate / sodium benzoate) and possible Arginine Hydrcohloride or dialysis, admit to ICU

Meets discharge criteria?


Even after liver transplants both organic acidemias and maple syrup urine disease should still be included in this pathway.

Discharge, PMD follow up within 24 hours

Plus appropriate electrolytes at 1.5x maintenance

D10 NS infusion

Common Metabolic Disorders

Urea Cycle

  • Ornithine Transcarbamylase Deficiency (OTC)
  • Citrullinemia

Organic Acidemia

  • Methylmalonic Acidemia (MMA)
  • Propionic Acidemia

Fatty Acid

  • Medium-chain acyl-coenzyme A dehydrogenase (MCAD) deficiency
  • Very long-chain acyl-coenzyme A dehydrogenase (VLCAD) deficiency


  • Maple Syrup Urine Disease

Population specific information

  • Vomiting/dehydration is an emergency in a metabolic patient
  • Do not delay fluids with dextrose to wait for labs
  • Elevated ammonia is often, but not always the cause of altered mental status in a patient with a metabolic disorder

1 or more signs of poor hydration

  • Poor oral intake
  • Minimal urine output
  • Clinical signs of dehydration

Complete Metabolic Panel, Serum
ISTAT Venous Blood Gas and Lactate, Serum
Ammonia, Serum


Discharge criteria

  • Reassuring vital signs
  • Tolerating PO
  • Well-appearing
  • No social/family concerns
  • Reliable follow up in 24 hours
  • Parents comfortable and understand discharge plan
  • Provider comfortable with outpatient therapy

ICU criteria

  • Unstable vital signs
  • Poor perfusion despite fluid administration
  • Mental status changes
  • Ammonia > 200

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