Reye's syndrome
Reye's syndrome: Excerpt from Professional Guide to Diseases (Eighth Edition)
Reye’s syndrome is an acute illness affecting children and, less commonly, adults. It causes fatty infiltration of the liver with concurrent hyperammonemia, encephalopathy, and increased intracranial pressure (ICP). In addition, fatty infiltration of the kidneys, brain, and myocardium may occur.
Prognosis depends on the severity of central nervous system depression. Until recently, mortality was as high as 90%. Today, ICP monitoring and, consequently, early treatment of increased ICP, along with other treatment measures, have cut mortality to about 20%. Death is usually a result of cerebral edema or respiratory arrest. Comatose patients who survive may have residual brain damage.
Causes and incidence
Reye’s syndrome typically begins within 1 to 3 days of an acute viral infection, such as an upper respiratory tract infection, type B influenza, or varicella (chickenpox). Incidence commonly rises during influenza outbreaks and may be linked to salicylate use. For this reason, use of aspirin for children younger than age 15 isn’t recommended. The Reyes Syndrome Foundation warns against the use of salicylates, even in topical preparations, when a viral illness is suspected.
In Reye’s syndrome, damaged hepatic mitochondria disrupt the urea cycle, which normally changes ammonia to urea for its excretion from the body. This results in hyperammonemia, hypoglycemia, and an increase in serum short-chain fatty acids, leading to encephalopathy. Simultaneously, fatty infiltration occurs in renal tubular cells, neuronal tissue, and muscle tissue, including the heart.
Reye’s syndrome affects children from infancy to adolescence and occurs equally in boys and girls. Peak incidence is at age 6.
Signs and symptoms
The severity of the child’s signs and symptoms varies with the degree of encephalopathy and cerebral edema. In any case, Reye’s syndrome develops in five stages. After the initial viral infection, a brief recovery period follows when the child doesn’t seem seriously ill. A few days later, he develops intractable vomiting; lethargy; rapidly changing mental status (mild to severe agitation, confusion, irritability, and delirium); rising blood pressure, respiratory rate, and pulse rate; and hyperactive reflexes.
Reye’s syndrome commonly progresses to coma. As coma deepens, seizures develop, followed by decreased tendon reflexes and, usually, respiratory failure.
Increased ICP, a serious complication, is now considered the result of an increased cerebral blood volume causing intracranial hypertension. Such swelling may develop as a result of acidosis, increased cerebral metabolic rate, and an impaired autoregulatory mechanism.
Diagnosis
A history of a recent viral disorder with typical clinical features strongly suggests Reye’s syndrome. An increased serum ammonia level, abnormal clotting studies, and hepatic dysfunction confirm it. Testing serum salicylate level rules out aspirin use. Absence of jaundice despite increased liver aminotransferase levels rules out acute hepatic failure and hepatic encephalopathy.
Abnormal test results may include:
❑Liver function studies: aspartate aminotransferase and alanine aminotransferase elevated to twice normal levels; bilirubin level usually normal
❑Liver biopsy: fatty droplets uniformly distributed throughout cells
❑Cerebrospinal fluid (CSF) analysis: white blood cell count less than 10/µl; with coma, increased CSF pressure.
❑Coagulation studies: prothrombin time and partial thromboplastin time prolonged
❑Blood values: serum ammonia levels elevated; serum glucose levels normal or, in 15% of cases, low; serum fatty acid and lactate levels increased.
Treatment
For treatment guidelines, see Stages of treatment for Reye’s syndrome.
Special considerations
Advise parents to give nonsalicylate analgesics and antipyretics such as acetaminophen. For more information, refer parents to the National Reye’s Syndrome Foundation.
Pictures
Book Source Details
- Book Title: Professional Guide to Diseases (Eighth Edition)
- Author(s): Springhouse
- Year of Publication: 2005
- Copyright Details: Professional Guide to Diseases (Eighth Edition), Copyright © 2005 Lippincott Williams & Wilkins.
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- Hepatitis
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- Hepatomegaly
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- Hepatomegaly
- "The Diagnostic Approach to Symptoms and Signs in Pediatrics" (2006)
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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