Reye's Syndrome

What is Reye's syndrome?

Reye's syndrome (RS) is a rare disorder that affects many parts of the body—including the brain, blood, and liver. People with RS often have low blood sugar and higher levels of ammonia and acidity in the blood. This causes severe and sudden brain swelling. 

RS is a two-phase illness because it generally happens when someone has just had a viral infection—such as a cold or respiratory infection, the flu, or chicken pox. It also can develop five to seven days after the start of the viral illness. It’s most common during flu season in the fall and winter.

Symptoms of RS

Symptoms may include:

• Nausea and vomiting that doesn’t stop
• Rapid breathing
• Being unusually sleepy or sluggish
• Sudden personality changes, such as irritability or combativeness
• Anxiety, disorientation, or confusion (delirium)
• Seizures
• Loss of consciousness
• Coma

People with Reye’s syndrome may bleed more if cut or injured, and blood may not clot or stop like it should.

Who is more likely to get Reye’s syndrome?

Anyone—at any age—can get RS, but it’s most common in children and teens. The cause of Reye's syndrome is unknown. Studies have shown a link between taking aspirin (salicylate) during a viral illness and developing Reye's syndrome. Because of this, healthcare professionals recommend acetaminophen or ibuprofen instead of aspirin for children. Salicylate is also found in other over-the-counter medicines, so be sure to read labels and talk with your healthcare provider if you’re not sure if a medicine is safe for children. Vaccinations can prevent many viral infections. 

In some children, a rare metabolic condition called medium-chain acyl-CoA dehydrogenase (MCAD) deficiency can cause symptoms similar to Reye's syndrome. In MCAD deficiency, which is a fatty oxidation disorder, the body can’t break down certain fats to turn them into energy due to an enzyme that is missing or doesn’t work. For people with this disorder, taking aspirin when they have a viral illness is more likely to trigger RS symptoms.  

How is Reye’s syndrome diagnosed and treated?

Diagnosing RS

Reye's syndrome is often hard to diagnose because it has the same symptoms as many other diseases, such as encephalitis and meningitis.  A healthcare provider may suspect that a person has RS if they have a viral illness that is followed by symptoms of Reye's syndrome such as vomiting or personality changes (being agitated, confused, or disoriented). To rule out disorders with similar symptoms and diagnose RS, doctors may order the following tests: 

• Lab tests of blood or urine to check ammonia levels in the blood or identify toxins in the urine
• Imaging tests like an MRI (magnetic resonance imaging) or CT (computed tomography) scan to show brain swelling that may explain personality changes and disorientation
• A spinal tap to test cerebrospinal fluid to diagnose swelling or an infection of the brain and spinal cord
• A screening test that can show if a person has a fatty oxidation disorder to rule out MCAD deficiency

Find out more about neurological diagnostic tests and procedures.

Treating RS 

Reye’s syndrome is a serious condition. Seek immediate medical attention at the nearest emergency department if symptoms appear soon after a viral illness. Reye’s syndrome can lead to seizures, loss of consciousness, a coma, and death. While there is no cure for RS, treatments are available to help manage symptoms and address other conditions that may develop.

If a person is diagnosed with RS, a healthcare provider will admit them into the intensive care unit immediately to receive treatment. Treatment focuses on preventing brain damage by reducing brain swelling, stopping further damage in the liver and blood from lack of oxygen, and preventing lung problems. People with RS will be in the hospital for a few days up to a few weeks until they are healthy enough to leave.  

Recovery depends on how much brain swelling the person has and how much ammonia is in their blood. Many children recover completely, while others may have lasting problems, including: 

• Muscle weakness
• Nerve damage
• Memory loss
• Learning disabilities
• Vision and hearing loss
• Speech and language problems
• Difficulty doing everyday tasks
• Brain damage
• Epilepsy

Early detection and treatment greatly improve the rate of recovery and survival. 

What are the latest updates on Reye’s syndrome?

NINDS, a part of the National Institutes of Health (NIH), is the leading federal funder of research on the brain and nervous system, including disorders such as Reye's syndrome. NINDS and other NIH institutes have supported research to better understand, diagnose, and treat RS and related disorders. This includes research on how and why RS develops and the association with taking aspirin. 

For more information on research about RS, check NIH RePORTER, a searchable database of current and past research projects funded by NIH and other federal agencies. RePORTER also has links to publications and resources from these projects.

For research articles and summaries on RS, search PubMed, which contains citations from medical journals and other sites.

How can I or my loved one help improve care for people with Reye's syndrome?

Consider participating in a clinical trial so clinicians and scientists can learn more about RS and related disorders. Clinical research with human study participants helps researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.

All types of participants are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities to ensure that study results apply to as many people as possible, and that treatments will be safe and effective for everyone who will use them.

For information about participating in clinical research visit the NINDS Clinical Trials site and NIH Clinical Research Trials and You. Learn about clinical trials currently looking for people with RS at ClinicalTrials.gov, a searchable database of current and past clinical studies and research results.