Reye's syndrome

Diagnosing Reye's syndrome

See your GP immediately, or visit the nearest accident and emergency (A&E) department, if you think that your child may have Reye’s syndrome. If your child has taken aspirin, inform your GP or the healthcare professional who treats your child.

Ruling out other conditions

As Reye’s syndrome is such a rare condition, the first stage of diagnosis is to rule out other conditions that can cause similar symptoms. For example:

  • meningitis – an infection of the meninges (the protective membranes that surround the brain and spinal cord)
  • blood poisoning – a bacterial infection of the blood
  • encephalitis – inflammation of the brain

Inherited metabolic disorders

Inherited metabolic disorders affect the chemical reactions that take place in the body. Some can cause symptoms that are similar to Reye’s syndrome, so it is important to rule these out. Some inherited metabolic disorders can be treated to prevent the symptoms from returning.

If an inherited metabolic disorder is diagnosed, it may be necessary to check the child's brothers or sisters to see if they also have the condition. 


During the first stage of diagnosis, blood and urine tests should be carried out to determine whether there is a build-up of toxins or bacteria in the blood, and to check whether the liver is functioning normally.

Special tests may be undertaken to measure the presence or absence of certain chemicals that could indicate an inherited metabolic disorder rather than Reye’s syndrome. 

Other tests that may be recommended include:

  • a computerised tomography (CT) scan
  • lumbar puncture
  • biopsy

These procedures are briefly described below.

CT scan

A computerised tomography (CT) scan, which produces detailed images of the body, may be used to check the pressure level in the brain.

See the Health A-Z topic about CT scans for more information.

Lumbar puncture

The CT scan may be followed by a lumbar puncture. This involves taking a sample of cerebrospinal fluid (CSF) from the base of the spine and checking to see if it has bacteria or viruses. CSF is the fluid that surrounds and protects the brain and spinal cord.

A lumbar puncture is useful for ruling out meningitis or encephalitis. However, paediatricians (specialists in conditions affecting children) will be cautious about doing a lumbar puncture if they think that the child may have brain swelling.

See the Health A-Z topic about Lumbar punctures for more information.


Finally, a liver biopsy may be done. This involves taking a small sample of the liver so that it can be closely examined under a microscope. Reye’s syndrome often causes distinctive changes to the cells of the liver, which can be detected using a biopsy.

See the Health A-Z topic about Biopsies for more information.

Last updated: 12 July 2012

Continue to next section: Treating Reye's syndrome