Reye's syndrome — acute encephalopathy and liver dysfunction in children and adolescents

Typical features and clinical course

Initial signs may be non‑specific and can include persistent vomiting and malaise following a viral illness. Neurological symptoms may progress from irritability and confusion to severe drowsiness, seizures, and coma as cerebral swelling increases. Laboratory testing frequently shows metabolic disturbances rather than a direct viral cause.

• Common early symptoms: repeated vomiting, lethargy, behavior change
• Neurological progression: confusion, seizure, decreased consciousness
• Evidence of liver involvement: hypoglycemia and impaired blood clotting may appear

Pathophysiology and diagnosis

The hallmark pathology is diffuse, microvesicular fatty change of the liver with minimal inflammation and evidence of mitochondrial dysfunction. This disrupts normal metabolism and leads to elevated blood ammonia and impaired glucose regulation. Diagnosis is clinical and supported by laboratory tests (ammonia, glucose, coagulation studies, liver enzymes) and imaging to assess cerebral edema. Affected brain structures are often referred to collectively as the brain in clinical descriptions.

History, prevention and outcomes

First described in the medical literature in the 20th century, the association between aspirin given during childhood viral infections and this syndrome led to public health recommendations that greatly reduced its occurrence. Prevention focuses on avoiding aspirin in children and adolescents with fever or viral symptoms; acetaminophen and ibuprofen are commonly advised alternatives unless otherwise directed by a clinician.

Treatment, differential diagnosis and notable points

Treatment is supportive and delivered in an intensive care setting when needed: control of intracranial pressure, correction of metabolic abnormalities, and management of bleeding risks. Several inherited metabolic disorders (so‑called Reye‑like illnesses, such as fatty acid oxidation defects) can mimic Reye's syndrome and should be considered in the differential diagnosis. Prognosis ranges from full recovery to long‑term neurological impairment or death, depending on severity and timeliness of care.