Reye's syndrome is a rare and severe illness usually affecting children and teenagers linked with viral infections and taking aspirin during childhood.
Reye's syndrome can be life threatening.
For this reason, the medicines regulator MHRA says aspirin should not be given to under-16s unless under specific recommendations from a doctor.
Some mouth gels contain aspirin-like ingredients including salicylate salts, which are also unsuitable for children.
Although there has been a lot of research into the causes of Reye's syndrome, it is still not completely understood.
Even if it is diagnosed and treated early, some children may be left with permanent brain damage and problems with attention, speech, movement, vision or hearing.
Symptoms of Reye's syndrome
The symptoms of Reye's syndrome include vomiting, drowsiness, a lack of energy, seizures, breathing changes and an altered mental state, such as irritability and confusion. In severe cases, the child may go into a coma.
Reye's syndrome causes liver problems and pressure on the brain.
Reye's syndrome is a medical emergency and the child needs urgent medical advice. Make sure the emergency medical team knows if the child has had aspirin or may have taken it.
Reye's syndrome diagnosis
The diagnosis of Reye's syndrome will be made based on symptoms, whether aspirin use is suspected, plus the results of laboratory tests. Other conditions causing similar symptoms will need to be ruled out.
Blood and urine tests will be carried out to check the liver function, and for toxins or bacteria in the blood.
Scans may be needed to check the brain for swelling. Spinal fluid may be taken with a lumbar puncture to check for the presence of bacteria or viruses.
Tissue samples may need to be taken from the liver for laboratory tests. This is called a liver biopsy.
Reye's syndrome treatment
A child with Reye's syndrome will usually be taken to an intensive care ward where measures will be taken to reduce swelling in the brain, control any seizures and remove toxins from the body.
Help may be given with breathing through a ventilator.
The child's overall condition should improve after swelling in the brain is brought under control, but it can be some weeks before they are well enough to leave hospital and any lasting complications become apparent.