Reye's syndrome involves brain damage (encephalopathy) and liver damage of an unknown cause. It is associated with the use of aspirin to treat chickenpox or influenza in children.

Reye's syndrome is most often seen in children from 4 to 12 years old, with a peak incidence at age 6. It is often associated with children who are given aspirin-containing medicines while they have either chickenpox (varicella) or the flu (influenza).

The illness has a rapid onset and symptoms may vary greatly. Changes in mental status occur including delirium, combative behavior, and coma.

Typically, Reye's syndrome follows an upper respiratory infection (URI) or chickenpox by about a week. It frequently begins with vomiting, which is persistent over many hours.

The vomiting is rapidly followed by irritable and combative behavior. As the condition progresses, the child may become semi-conscious or stuporous. Ultimately, seizures and coma develop, which can quickly lead to death.

• A history of preceding URI or chickenpox (about 1 week previously)
• Nausea and vomiting (possible)
• Mental status changes
• Lethargy
• Confusion
• Combative behavior
• Loss of consciousness or coma may develop
• Seizures
• Unusual posturing (decerebrate posture -- the arms are extended straight and turned toward the body, the legs are held straight and the toes are pointed downward)

• Weakness in arms or legs
• Muscle function loss or paralysis of the arms or legs
• Double vision
• Speech difficulties
• Hearing loss

• Blood chemistry tests shows low glucose (hypoglycemia)
• Elevated liver enzymes (liver function tests)
• Elevated serum ammonia test
• A liver biopsy
• A spinal tap for cerebral spinal fluid analysis
• A neurological examination
• A head CT or head MRI scan that rules out other causes of mental status changes
• A variety of other tests that may be indicated

Intensive, supportive care is needed, although specific treatment measures have not been determined.

Intravenous fluids to provide electrolytes and glucose are given. Steroids are given to reduce swelling in the brain. Intensive monitoring of the pressure within the brain, blood gases, and blood pH is required. Support for breathing using a mechanical ventilator may be needed during a deep coma.

When this illness was more common, high-technology treatments such as charcoal hemoperfusion (to filter out blood toxins) were used with some success.

The outcome is related to the severity of the coma as well as other factors. The average death rate is about 40%. The outcome for those who survive the acute episode is good. The incidence of permanent brain damage is not known, but it is thought to be related to the severity of the coma.

• Permanent brain damage
• Coma

Go to the emergency room or call the local emergency number (such as 911) immediately if your child has confusion, lethargy, or other mental changes, particularly if you suspect this illness.

NEVER GIVE ASPIRIN TO A CHILD unless specifically authorized by a physician. When a child is taking aspirin, steps must be taken to minimize the risk of acquiring a viral illness such as influenza and varicella vaccinations.

In addition, other over-the-counter medications such as Pepto-Bismol and compounds containing oil of wintergreen also contain salycilates, and should not be given to children with colds or fever.