Reye’s Syndrome (RS) is a rare form of encephalopathy (brain injury) that usually follows an acute viral illness, such as chickenpox or influenza. The use of salicylates (aspirin) during such an illness dramatically increases the risk of RS.
Once the association between aspirin and RS was identified, the incidence of this syndrome in the United States dropped from several hundred cases annually to fewer than a dozen.
The exact cause of RS is unknown. The disease affects mitochondrial function and interferes with fatty acid and carnitine metabolism.
RS resembles several inherited metabolic disorders. It is possible that viral infection unmasks an underlying metabolic abnormality that is further aggravated by aspirin.
Although RS occurs in adults, it is almost exclusively seen in children under the age of 18 years. Adults usually recover fully, but the syndrome causes significant mortality and disability in younger patients. (The Merck Manual, 18th Edition. 2006:2401-02)
Signs, Symptoms and Stages of Reye’s Syndrome
RS is graded from Stage I to V depending on its severity. Initial viral symptoms are typically followed in 5 to 7 days by nausea and persistent vomiting and a sudden change in mental status. In children under 2, initial symptoms may be diarrhea and rapid breathing.
Progression through the five stages is typically rapid.
Reye’s Syndrome Stages
Stage I
- Persistent, heavy vomiting
- Lethargy (sleepiness)
- Confusion or amnesia
- Nightmares
Stage II
- Disorientation
- Irritable, aggressive, or combative behavior
- Hyperventilation (rapid respiratory rate)
- Fatty liver infiltration (diagnosed by biopsy)
- Hyperactive reflexes
Stage III
- Stupor
- Cerebral edema (brain swelling)
- Liver enlargement (in 40%)
Stage IV
- Deepening coma
- Decorticate and decerebrate posturing
- Pupils enlarged, minimally responsive to light
- Liver failure
Stage V
- Deep coma
- Fixed, dilated pupils
- Seizures
- Flaccidity
- High serum ammonia level
Complications of Reye’s Syndrome
Most complications resolve as recovery occurs:
- Electrolyte abnormalities
- Acid-base disturbances
- Hypoglycemia (low blood sugar)
- Fluid disturbances due to diabetes insipidus or inappropriate secretion of anti-diuretic hormone (secondary to brain damage)
- Low blood pressure
- Cardiac arrhythmias
- Pancreatitis
- Bleeding abnormalities; GI hemorrhage
- Aspiration pneumonia
- Poor thermoregulation
- Prolonged coma
- Death
- For survivors who developed seizures or posturing during their illness, up to 30% are permanently afflicted with mental retardation, seizure disorders, cranial nerve palsies, or abnormalities of motor function
Treatment of Reye’s Syndrome
Early recognition and management of RS are critical. Treatment is generally supportive:
- Control of intracranial pressure with ventilator support (hyperventilation), fluid restriction, corticosteroids, and diuretics
- Blood sugar control, sometimes requiring concentrated IV glucose solutions
- Infusions of plasma or vitamin K to control bleeding
- Occasionally, dialysis, exchange transfusions, and medically-induced coma or paralysis are necessary to address complications
Prevention of Reye’s Syndrome
Avoidance of aspirin and other salicylate-containing products (including over-the-counter preparations like Pepto-Bismol or Alka-Seltzer) in individuals younger than eighteen is of major importance in preventing RS. For children who must take aspirin for other illnesses (e.g., Kawasaki disease, juvenile rheumatoid arthritis), immunization for preventable viral diseases, such as influenza and chickenpox, is vital. Aspirin should be withheld for several weeks following a chickenpox vaccination.
The incidence of Reye’s syndrome has dropped significantly since its association with aspirin was recognized. For those cases that do occur, the overall mortality rate is still around 20%, and complications can be severe in survivors.
(Belay ED, Bresee JS, Holman RC, et al. Reye’s syndrome in the United States from 1981 through 1997. NEJM 1999;340(18)1377-82 and Sullivan KM, et al. Epidemiology of Reye’s syndrome, United States, 1991-1994: Comparison of CDC surveillance and hospital admission data. Neuroepidemiology 2000;19:338-44)
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