Reye’s Syndrome

DEFINITION
Reye’s syndrome is a postinfectious triad consisting of encephalopathy, fatty liver degeneration, and transaminase elevation.

EPIDEMIOLOGY & DEMOGRAPHICS
• During the 1970s, 300 to 600 cases were being reported yearly in the U.S.
• Since the mid-1980s, after the understanding that aspirin is associated with Reye’s syndrome, the yearly count has fallen to <20 cases
• Seasonal relation with influenza and varicella outbreaks
• Age: rare in persons aged >18 yr; peak age (in the U.S.) is 6 to 8 yr
• Case-fatality rate: 25% to 50%

ETIOLOGY
• Temporal association with influenza and varicella infection
• Epidemiologic association with aspirin or other salicylate use to treat the viral infection
• Possible association with aflatoxin and pesticides
• Pathology

• Liver: no inflammation; the striking finding is panlobular microvesicular hepatocyte infiltration on light microscopy and mitochondrial injury on electron microscopy
• Brain: no inflammation but cerebral edema and anoxic degeneration
• Pathogenesis: not fully understood but mitochondrial dysfunction is clearly center stage

DIFFERENTIAL DIAGNOSIS
• Inborn errors of metabolism (e.g., carnitine deficiency, ornithine transcarbamylase deficiency)
• Salicylate or amiodarone intoxication
• Jamaican vomiting sickness
• Hepatic encephalopathy of any cause
• Table E1-433 describes diseases that present a clinical or pathologic picture resembling
Reye’s syndrome.

LABORATORY TESTS
• Elevated transaminase (alanine aminotransferase and aspartate aminotransferase)
• Elevated ammonia level
• Occasional elevation of creatine phosphokinase, lactate dehydrogenase, and bilirubin and prolongation of prothrombin time
• Occasional hypoglycemia (in patients <4 yr)
• Cerebrospinal fluid is normal or contains <8 white blood cells per milliliter
• Rarely a liver biopsy is indicated (in infants or in recurrent cases)

TREATMENT
• Supportive
• Mannitol, glycerol, or hyperventilation for cerebral edema if present
• Interferon-alfa (experimental)
• Prevention
Influenza vaccine
Varicella vaccine
Avoidance of aspirin in children, especially during influenza and varicella outbreaks