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NOTE: A surveillance case definition is a set of uniform criteria used to define a disease for public health surveillance. Surveillance case definitions enable public health officials to classify and count cases consistently across reporting jurisdictions. Surveillance case definitions are not intended to be used by healthcare providers for making a clinical diagnosis or determining how to meet an individual patient’s health needs.

Clinical Criteria

An illness that meets all of the following criteria:

  • Acute, noninflammatory encephalopathy that is documented clinically by a) an alteration in consciousness and, if available, b) a record of the cerebrospinal fluid (CSF) containing less than or equal to 8 leukocytes/ or a histologic specimen demonstrating cerebral edema without perivascular or meningeal inflammation
  • Hepatopathy documented by either a) a liver biopsy or an autopsy considered to be diagnostic of Reye syndrome or b) a threefold or greater increase in the levels of the serum glutamic-oxaloacetic transaminase (SGOT), serum glutamic-pyruvic transaminase (SGPT), or serum ammonia
  • No more reasonable explanation for the cerebral and hepatic abnormalities

Case Classification


A case that meets the clinical criteria