A rare disease that occurs mainly in children aged 4-16 years, and affects all organs of the body, particularly the liver and the brain. It’s usually preceded by a viral infection like the flu, cold or chickenpox, with symptoms of nausea, vomiting, lethargy and, in later stages, changed behaviour or mental state. This syndrome isn’t contagious and its cause is unknown, although taking aspirin can increase the risk of contracting it. Its effects can be mild in some children, but lethal in others.