Reye Syndrome

Reye syndrome is an acute illness in which encephalopathy develops alongside liver dysfunction, usually several days after a viral infection. The classic timing is 3–7 days after influenza, chickenpox, or another viral illness. Salicylate exposure during the infection is strongly associated with the syndrome, although the exact trigger is not completely established. The underlying problem is mitochondrial dysfunction. Liver cells lose efficiency in fatty-acid oxidation, producing microvesicular fatty change and impaired hepatic metabolism. Ammonia rises and contributes to brain dysfunction and cerebral swelling. This explains why a child can move quickly from vomiting and unusual behaviour to seizures, coma, and signs of increased intracranial pressure. Reye syndrome is an acute non-inflammatory encephalopathy; it is not simply a worsening of the original viral infection. The liver may be enlarged and liver enzymes may rise even when the most striking bedside problem is neurologic. That mismatch matters. A child who appears primarily confused or drowsy after a recent viral illness still requires assessment for hepatic dysfunction and metabolic complications.