Reye's syndrome is a very rare condition that can cause serious liver and brain damage. If it's not treated promptly it may result in permanent brain injury or death.

Reye's syndrome mainly affects children and young adults under 20 years of age. Some cases in older adults have also been reported.

Signs and symptoms

The symptoms of Reye's syndrome usually begin a few days after a viral infection.

Initial symptoms can include:

  • persistent, effortless vomiting 
  • listlessness (a lack of interest or enthusiasm) and a loss of energy
  • drowsiness
  • rapid breathing
  • seizures (fits)

As the condition progresses, the symptoms may become more severe and wide ranging, and can include:

  • personality changes, such as extreme irritability, agitation or aggressive behaviour
  • delirium (a severe state of mental confusion and anxiety sometimes associated with hallucinations)
  • coma (loss of consciousness)

Seeking medical advice

See your GP or go to your nearest accident and emergency (A&E) department immediately if you think you or your child may have Reye's syndrome.

Although the symptoms will probably not be the result of Reye's syndrome, they still need to be checked by a doctor.

Inform the doctor if your child has taken aspirin, as the use of aspirin in children has been linked to Reye's syndrome (see below). However, even if your child isn't known to have taken aspirin, the condition shouldn't be ruled out.

What causes Reye's syndrome?

The exact cause of Reye's syndrome is unknown, but most cases have occurred in children and young adults recovering from a viral infection – typically, but not exclusively, flu or chickenpox – and in most of these cases they had taken aspirin to treat their symptoms.

In Reye's syndrome, it is thought that tiny structures within the cells called the mitochondria become damaged.

Mitochondria provide cells with energy and they are particularly important for the healthy functioning of the liver because they provide energy for many of its vital functions, such as filtering toxins from the blood and regulating blood sugar levels.

If the liver loses its energy supply, it begins to fail. This can result in a dangerous build-up of toxic chemicals in the blood, such as ammonia, which can damage the entire body and can cause the brain to swell.

Diagnosing Reye's syndrome

As Reye's syndrome is such a rare condition, other conditions that can cause similar symptoms need to be ruled out.

These include meningitis (inflammation of the protective membranes surrounding the brain and spinal cord), encephalitis (inflammation of the brain) and a group of conditions called inherited metabolic disorders (conditions that affect the chemical reactions taking place in your body).

The most common example of an inherited metabolic disorder is medium-chain acyl-CoA dehydrogenase deficiency (MCADD).

Blood tests 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 also be undertaken to check for the presence or absence of certain chemicals that could indicate an inherited metabolic disorder.

Other tests that may be recommended include:

  • a computerised tomography (CT) scan to check for brain swelling
  • a lumbar puncture – where a sample of cerebrospinal fluid (fluid that surrounds the brain and spinal cord) is removed from the spine using a needle to check for bacteria or viruses
  • a liver biopsy – where a small sample of liver tissue is removed and closely examined under a microscope to look for distinctive cell changes associated with Reye's syndrome

Treating Reye's syndrome

If Reye's syndrome is diagnosed, you or your child will need to be immediately admitted to an intensive care unit.

The aim of treatment is to minimise the symptoms of the condition and support the body's vital functions, such as breathing and blood circulation. It's also essential to protect the brain against permanent damage that can be caused by the brain swelling.

A number of medicines may be given intravenously (directly into a vein), such as:

  • electrolytes and fluids – to correct the level of salts, minerals and nutrients, such as glucose (sugar), in the blood
  • diuretics – medications to help rid the body of excess fluid and reduce swelling in the brain
  • ammonia detoxicants – medications to reduce the level of ammonia
  • anticonvulsants – medications to control seizures

A ventilator (breathing machine) may be used if you or your child needs help with their breathing.

Vital body functions will also be closely monitored, including the heart rate and pulse, the air flow to their lungs, blood pressure and body temperature.

Once the swelling of the brain has decreased, the rest of their body functions should return to normal within a few days, although it may be several weeks before you or your child are well enough to leave hospital.

Possible complications

As a result of advances in diagnosing and treating Reye's syndrome, the majority of children and young adults who develop the condition will survive, and some will make a full recovery.

However, the condition can leave some people with a degree of permanent brain damage caused by the swelling of their brain.

Long-term difficulties sometimes associated with Reye's syndrome include:

  • poor attention span and memory
  • some loss of vision or hearing
  • speech and language difficulties
  • problems with movement, dexterity and posture
  • difficulty swallowing (dysphagia)
  • difficulty with everyday tasks, such as dressing or using the toilet

If your child develops any long-term problems, an individual care plan will be drawn up to address their needs. This plan will be reassessed as they get older to accommodate any necessary changes in their care.

Read more about living with disability and information for carers.

Preventing Reye's syndrome

Because of the possible link between Reye's syndrome in children and aspirin, the Medicines and Healthcare products Regulatory Agency (MHRA) recommends that children under 16 years old should not take aspirin unless advised to do so by a doctor.

Painkillers such as paracetamol or ibuprofen can be used to reduce fever and relieve pain instead. Read more about treating a fever in children.

These alternative medications are not suitable for everyone, however, so you should still make sure you carefully read the leaflet that comes with them and ask your GP or pharmacist if you are unsure whether to use them.

Children under 16 should also not take any products containing:

  • acetylsalicylic acid
  • acetylsalicylate
  • salicylic acid
  • salicylate
  • salicylate salts

Bonjela and Bonjela Cool Mint Gel both contain salicylate salts, which have the same effect on the body as aspirin. See the Bonjela child advice Q&A for more information.

Aspirin should only be given to children under 16 on the advice of a doctor when it is felt the potential benefits outweigh the risks. For example, it may be recommended for children with the rare condition Kawasaki disease.

Page last reviewed: 15/12/2014

Next review due: 15/12/2016