Reye's syndrome

Infobox_Disease
Name = Reye's syndrome


Caption =
DiseasesDB = 11463
ICD10 = ICD10|G|93|7|g|90
ICD9 = ICD9|331.81
ICDO =
OMIM =
MedlinePlus = 001565
eMedicineSubj = emerg
eMedicineTopic = 399
MeshName = Reye+Syndrome
MeshNumber = C06.552.241.649

Reye's syndrome is a potentially fatal disease that causes numerous detrimental effects to many organs, especially the brain and liver. It is associated with aspirin consumption by children with viral diseases such as chickenpox.

The disease causes fatty liver with minimal inflammation, and severe encephalopathy (with swelling of the brain). The liver may become slightly enlarged and firm, and there is a change in the appearance of the kidneys. Jaundice is not usually present.cite book |last=Suchy| first= FJ, el al.| last2 =Sokol | first2 = RJ| last3 =Balistreri | first3 = WF|chapter= |title=Liver Disease in Children |publisher=Cambridge University Press| location=Cambridge |year=2007|pages=| isbn=0-5218-5657-4]

Early diagnosis is vital, otherwise death or severe brain damage may follow.

Causes

The precise mechanism by which Reye's syndrome occurs remains unknown. This serious illness is referred to as a “syndrome” because the clinical features that physicians use to diagnose it are quite broad. Many studies have demonstrated a strong association between aspirin taken for viral illnesses and the development of Reye’s syndrome. Some have claimed that acetaminophen (paracetamol) is a greater risk, but the only study [ [http://pediatrics.aappublications.org/cgi/content/abstract/80/5/638 A Catch in the Reye - Orlowski et al. 80 (5): 638 - Pediatrics ] ] to suggest this was too small and according to some sources, the conclusions by the authors seem flawed. [ [Remington PL, Sullivan K, Marks JS. A Catch in 'a Catch in the Reye'. Pediatrics 1988:82;676-677] ]

The Centers for Disease Control and Prevention (CDC), the U.S. Surgeon General, the American Academy of Pediatrics (AAP) and the Food and Drug Administration (FDA) recommend that aspirin and combination products containing aspirin not be given to children under 19 years of age during episodes of fever-causing illnesses. Hence, in the United States, it is advised that the opinion of a doctor or pharmacist be obtained before anyone under 19 years of age is given any medication containing aspirin (also known on some medicine labels as acetylsalicylate, salicylate, acetylsalicylic acid, ASA or salicylic acid). By comparison, current advice in the United Kingdom by the Committee on Safety of Medicines is that aspirin should not be given to those under the age of 16 years, unless specifically indicated in Kawasaki disease or prevention of blood clot formation. [cite book |title=British National Formulary for Children |chapter=2.9 Antiplatelet drugs |year=2007 |pages=p.151 |publisher=British Medical Association and Royal Pharmaceutical Society of Great Britain]

The serious symptoms of Reye's syndrome appear to result from damage to cellular mitochondria, at least in the liver, and there are a number of ways that aspirin could cause or exacerbate mitochondrial damage. An increased risk of developing Reye's syndrome is one of the main reasons that aspirin has not been recommended for use in children and teenagers, the age group for which the risk of lasting serious effects is highest.

History

The syndrome is named after Dr R. Douglas Reye, who, along with fellow Australians Dr. Graeme Morgan and Dr. Jim Baral, published the first study of the syndrome in 1963 in the The Lancet. [cite journal |author=Reye RD, Morgan G, Baral J |title=Encephalopathy and fatty degeneration of the viscera. A Disease entity in childhood|journal=Lancet |volume=2 |issue= |pages=749–52 |year=1963 |pmid=14055046 |doi=] In retrospect, the occurrence of the syndrome may have first been reported in 1929. Also in 1964, Dr. George Johnson and colleagues published an investigation of an outbreak of influenza B that described 16 children who developed neurological problems, four of whom had a remarkably similar profile to Reye’s syndrome. Some investigators refer to this disorder as Reye-Johnson syndrome, although it is more commonly called Reye's syndrome. During the late 1970s and early 1980s, studies in Ohio, Michigan and Arizona [cite journal|author=Mortimor, Edward A., Jr. et al|title=Reye Syndrome-Ohio, Michigan|journal=Morbidity and Mortality Weekly Report|issue=29:532|year=1980|url=http://pediatrics.aappublications.org/cgi/content/abstract/69/6/810|pmid=7079050] pointed to the use of aspirin during an upper respiratory tract or chickenpox infection as a possible trigger of the syndrome. Beginning in 1980, the CDC cautioned physicians and parents about the association between Reye’s syndrome and the use of salicylates in children and teenagers with chickenpox or viruslike illnesses. In 1982 the US Surgeon General issued an advisory and in 1986 the Food and Drug Administration required a Reye’s syndrome-related warning label for all aspirin-containing medications.

Presentation

ymptoms and signs

Reye's syndrome progresses through five stages, explained below:
* Stage I
** Persistent, heavy vomiting that is not relieved by eating
** Generalized lethargy
** General mental symptoms, e.g. confusion
** Nightmares
* Stage II
** Stupor caused by minor brain inflammation
** Hyperventilation
** Fatty liver (found by biopsy)
** Hyperactive reflexes
* Stage III
** Continuation of Stage I and II symptoms
** Possible coma
** Possible cerebral edema
** Rarely, respiratory arrest
* Stage IV
** Deepening coma
** Large pupils with minimal response to light
** Minimal but still present hepatic dysfunction
* Stage V
** Very rapid onset following stage IV
** Deep coma
** Seizures
** Respiratory failure
** Flaccidity
** Extremely high blood ammonia (above 300mg per 100mL of blood)
** Death

Prognosis

Documented cases of Reye’s syndrome in adults have only been very rarely reported. The recovery of adults with the syndrome is generally complete, with liver and brain function returning to normal within two weeks of the illness. In children however, mild to severe permanent brain damage is possible, especially in infants. Over thirty percent of the cases reported in the United States from 1981 through 1997 resulted in mortality.

Differential diagnosis

Causes for similar symptoms include
* Various inborn metabolic disorders
* Viral encephalitis
* Drug overdose or poisoning
* Head trauma
* Hepatic failure due to other causes
* Meningitis
* Renal failure

Epidemiology

Reye’s syndrome occurs almost exclusively in children, and while a few rare adult cases reported over the years, adult cases do not typically show permanent neural or liver damage. Unlike in the UK , the surveillance for Reye’s syndrome in the US is focused on patients under 18 years of age.

In 1980, after CDC began cautioning physicians and parents about the association between Reye’s syndrome and the use of salicylates in children with chickenpox or viruslike illnesses, the incidence of Reye's syndrome in the United States began to decline. In the United States between 1980 and 1997, the number of reported cases of Reye’s syndrome decreased from 555 cases in 1980 to about 2 cases per year since 1994. During this time period 93% of reported cases for which racial data were available occurred in whites and the median age was six years. A viral illness occurred in 93% of cases in the preceding three week period. For the period 1991-1994, the annual rate of hospitalizations due to Reye’s syndrome in the US was estimated to be between 0.2 and 1.1 per million population less than 18 years of age.

During the 1980s, a case-control study carried out in the United Kingdom also demonstrated an association between Reye’s syndrome and aspirin exposure. [cite journal |author=Hall SM, Plaster PA, Glasgow JF, Hancock P |title=Preadmission antipyretics in Reye's syndrome |journal=Arch. Dis. Child. |volume=63 |issue=7 |pages=857–66 |year=1988 |pmid=3415311 |doi=] In June 1986, the United Kingdom Committee on Safety of Medicines issued warnings against the use of aspirin in children under 12 years of age and warning labels on aspirin-containing medications were introduced. UK surveillance for Reye’s syndrome documented a decline in the incidence of the illness after 1986. The reported incidence rate of Reye’s syndrome decreased from a high of 0.63 per 100,000 population less than 12 years of age in 1983/84 to 0.11 in 1990/91.

From November 1995 to November 1996 in France, a national survey of pediatric departments for children under 15 years of age with unexplained encephalopathy and a threefold (or greater) increase in serum aminotransferase and/or ammonia led to the identification of nine definite cases of Reye’s syndrome (0.79 cases per million children). Eight of the nine children with Reye’s syndrome were found to have been exposed to aspirin. In part because of this survey result, the French Medicines Agency reinforced the international attention to the relationship between aspirin and Reye’s syndrome by issuing its own public and professional warnings about this relationship. [cite journal |author=Autret-Leca E, Jonville-Béra AP, Llau ME, "et al" |title=Incidence of Reye's syndrome in France: a hospital-based survey |journal=Journal of clinical epidemiology |volume=54 |issue=8 |pages=857–62 |year=2001 |pmid=11470397|doi=10.1016/S0895-4356(00)00366-8]

Footnotes