Reye Syndrome Differential Diagnoses

Updated: Apr 02, 2015
  • Author: Debra L Weiner, MD, PhD; Chief Editor: Kirsten A Bechtel, MD  more...
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Diagnostic Considerations

Conditions that may mimic Reye syndrome include inborn errors of metabolism (IEMs), other hepatic illnesses, neuromuscular diseases, meningitis, encephalitis, obtundation due to intussusception, adverse drug reactions, and toxic exposures to chemicals and plants that cause hepatocellular damage and encephalopathy.

Inborn errors that may mimic Reye syndrome include fatty-acid oxidation defects, particularly medium-chain acyl-CoA dehydrogenase deficiency and long-chain acyl dehydrogenase deficiency; amino and organic acidopathies; urea-cycle defects; disorders of carbohydrate metabolism; and disorders of oxidative phosphorylation. Future discovery of other IEMs may ultimately explain even more of these cases.

Factors that increase concern for an IEM include the following:

  • No viral prodrome
  • No exposure to aspirin or toxin with association to Reye syndrome
  • Patients younger than 3 years (in particular, those younger than 1 year)
  • Patient or family history of Reye syndrome–like illness
  • Preexisting failure to thrive
  • Baseline neurologic abnormalities
  • Liver dysfunction or elevated ammonia level, particularly if elevated for longer than 1 week with or without waxing and waning

The differential diagnosis includes conditions that can cause vomiting and altered level of consciousness. The distinction between true Reye syndrome and Reye-like syndrome is often unclear.

Differential Diagnoses