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How long does Reye’s syndrome last?

Reye’s syndrome is a rare but serious condition that causes swelling in the liver and brain. It primarily affects children and teenagers recovering from viral infections like chickenpox or the flu. Reye’s syndrome usually comes on quickly and can be fatal if not treated right away, so it’s important to be familiar with its symptoms and duration.

What is Reye’s Syndrome?

Reye’s syndrome is named after Dr. R. Douglas Reye, who first described the condition in 1963. It is a rapidly progressing brain and liver disorder that can occur after certain viral infections. The viruses that have been associated with Reye’s syndrome include:

  • Influenza B
  • Varicella (chickenpox)
  • Herpes simplex
  • Epstein-Barr
  • Enteroviruses

Reye’s syndrome typically affects children between the ages of 4-15 years old. Cases in infants and adults are less common. It tends to occur more often in boys than girls.

The exact cause of Reye’s syndrome is unknown, but it appears to be related to how the body metabolizes fatty acids during recovery from a viral illness. Accumulation of fatty acids and ammonia in the blood stream is thought to contribute to the liver and brain swelling.

Use of aspirin to treat symptoms of the preceding viral infection also increases the risk of Reye’s syndrome. For this reason, aspirin is no longer recommended for children under 12 years old.

Signs and Symptoms

The signs and symptoms of Reye’s syndrome usually appear 3-7 days after the viral infection begins improving. The early symptoms may be very subtle and can include:

  • Persistent or frequent vomiting
  • Listlessness, weakness, extreme fatigue
  • Personality changes, confusion, disorientation
  • Agitation, combative behavior
  • Seizures
  • Loss of consciousness, coma

As Reye’s syndrome progresses, more serious symptoms arise from swelling in the liver and brain. These can include:

  • Jaundice (yellowing skin and eyes)
  • Abdominal pain
  • Enlarged liver
  • Involuntary movements, tremors, rigid muscle tone
  • Cortical thumb sign (fingers curl inward when fist clenched)
  • Cerebellar ataxia (unsteady gait, dysarthria)

Rapid breathing and elevated heart rate may also occur. In the most severe cases, intracranial pressure increases resulting in uncontrolled vomiting, seizures, dilated pupils, and loss of life functions.


Doctors may suspect Reye’s syndrome based on the patient’s symptoms and history of a recent viral illness. However, there are no specific tests to confirm a diagnosis. Tests that may help support a diagnosis include:

  • Blood ammonia test – elevated levels suggest Reye’s syndrome
  • Liver function tests – increased liver enzymes indicate liver injury
  • Blood glucose test – hypoglycemia often present
  • CSF test – increased pressure indicates brain swelling
  • MRI – detects brain edema
  • Liver biopsy – confirms fatty liver deposits

Reye’s syndrome is primarily a clinical diagnosis. The doctor will exclude other potential causes, like drug toxicity, metabolic disorders, and stroke.

Duration of Reye’s Syndrome

With aggressive treatment, many children with Reye’s syndrome can recover fully. However, the duration of the illness can vary greatly depending on the severity.

In milder cases, symptoms may persist for up to one week. More typically, symptoms last 2-4 weeks before full recovery. In the most severe cases that progress to coma and brain stem involvement, death can occur within 1-2 days.

Some factors that influence the duration and severity of Reye’s syndrome include:

  • How quickly treatment is started – faster treatment leads to shorter, milder illness
  • Age – teenagers more often have severe, prolonged course
  • Liver vs. brain involvement – brain swelling causes more damage
  • Peak ammonia level – higher levels predictive of coma

With intensive care treatment, coma typically lasts about 5-7 days. If the person survives, they may spend 2-3 weeks hospitalized and could have longer lasting problems.

Recovery and Prognosis

Up to 80% of Reye’s syndrome cases will fully recover with supportive medical care and monitoring. However, the recovery process can be prolonged.

Reye’s syndrome has a mortality rate of over 40% overall. Children who progress to coma have a mortality rate greater than 50%. Surviving a coma often means significant brain damage.

Possible long-term effects of Reye’s syndrome may include:

  • Cognitive impairments
  • Speech and language deficits
  • Memory problems
  • Motor/movement problems
  • Behavioral changes
  • Seizures
  • Hearing loss
  • Vision loss

The severity of ongoing problems depends on the degree of brain swelling that occurred. Regular neurologic exams and rehabilitation can help children recover mentally and physically.


There are no treatments that specifically target Reye’s syndrome. Care focuses on quickly diagnosing the condition, monitoring for complications, and providing intensive supportive management. Key aspects of treatment include:

  • Hospitalization – Usually in pediatric ICU due to risk of rapid deterioration
  • Medications – Mannitol to reduce brain swelling; anticonvulsants for seizures
  • Blood filtration – Hemodialysis to filter ammonia from blood
  • Liver protection – Nutritional supplements including arginine
  • Fluid/electrolyte balance – Careful IV fluid management
  • Nutritional support – IV feeding once stabilized
  • Physical/occupational therapy – For rehabilitation after discharge

With intensive monitoring and supportive treatments, many children with Reye’s syndrome can recover without permanent organ damage or brain injury.


There are no vaccines to prevent the viral infections associated with Reye’s syndrome. However, the following precautions may help lower the risk:

  • Get seasonal flu shots
  • Immunize children over 1 year against chickenpox
  • Wash hands frequently to avoid spread of viruses
  • Avoid aspirin use in children under 12 years
  • Quickly treat any fevers, flu symptoms, or chickenpox in children with acetaminophen or ibuprofen – not aspirin or ASA

Early diagnosis is also crucial. Contact a doctor right away if vomiting, confusion, lethargy, or other unusual behavior arises while a child is recovering from a viral illness.


Reye’s syndrome is a rapidly developing condition affecting the liver and brain, usually in children recovering from a viral infection. Symptoms tend to arise 3-7 days after the infection starts improving.

Milder cases may resolve within a week. More typically, symptoms last around 2-4 weeks before full recovery. In severe cases with brain stem involvement, coma and death can occur within 1-2 days.

With intensive supportive care including medications, dialysis, and nutritional supplements, the survival rate is over 60%. However, there may be lasting cognitive or physical impairments depending on the degree of brain swelling.

Rapid diagnosis and treatment are key. Preventing the antecedent viral illness can also lower risk. Reye’s syndrome duration can be shortened and outcomes improved with proactive monitoring and care.