Co-ingestion of aspirin and acetaminophen promoting fulminant liver failure: A critical review of Reye syndrome in the current perspective at the dawn of the 21st century.

In the paediatric population, there is some evidence of possible interaction, synergism, and co-toxicity of aspirin and acetaminophen. The toxicity of salicylates such as aspirin in this population is well known and documented, specifically in the form of Reye syndrome. The possible toxic synergism with aspirin and acetaminophen, however, is not previously described; though case reports suggest such co-toxicities with low levels of aspirin and other compounds can exist. In vitro studies into mechanistic processes of salicylate toxicity propose that there is a bi-directional link and potentiation with glutathione (GSH) depletion and salicylate toxicity. Data may suggest a plausible explanation for salicylate and acetaminophen toxic synergism. Further studies investigating this potential toxic synergism are warranted. Given the lack of awareness in the clinical community about potential toxic synergism between these relatively common medications, caution is advised in the co-administration of these drugs, particularly in communities using natural or alternative therapy.

REYE (RAY'S) SYNDROME: A PROBLEM EVERYONE SHOULD REMEMBER.

Reye syndrome is a rare but a very dangerous emergency that children and teenagers suffer. This threatening condition occurs during the treatment of fever in the clinical course of viral diseases with drugs containing acetylsalicylic acid and other salicylates. The high mortality rate from this disease is associated with the development of a rapidly progressing toxic encephalopathy and hepatic insufficiency. The etiology and pathogenesis of the Reye syndrome, despite the large number of investigations, is not clear enough. Today, special attention is paid to the development of so-called Reye-like syndromes in the context of congenital metabolic defects, although cases of the true Reye syndrome occur quite often. In spite of the long discussion among scientists, the effect of acetylsalicylic acid is an important factor of development of this pathological syndrome. Taking this fact into consideration, the use of acetylsalicylic acid by children, especially in case of colds, should be strictly controlled by a doctor and parents should be informed about possible complications, especially the development of the Reye syndrome. This issue is very urgent in countries with non-prescription antipyretics realization and a high percentage of self-treatment among patients.

[ACTION OF L-CARNITINE, CORVITIN AND THEIR COMBINATION ON FUNCTIONAL STATE OF LIVER IN EXPERIMENTAL MODEL OF REYE SYNDROME IN RATS].

Administration of Aacetylsalicylic acid in children with viral infections (influence B, chickenpox) can be related with development of Reye syndrome - severe encephalopathy and liver insufficiency with mortality in 50% of cases. During Reye syndrome most important is deficiency of carnitine and hepatocyte damage. Decreased amount of carnitine impairs the energy function of mitochondria and gluconeogenesis as well as production of urea. As a result develops toxic encephalopathy and liver insufficiency. The goal of the research was assessment of efficacy of L-Carnitine, Corvitin and their combination on functional state of liver in experimental model of Reye Syndrome in rats. The study was performed on mature white male Wistar rates with body mass 150-180g. 50 rats were randomly divided into 5 groups (10 rats in each group). The model of Reye syndrome was induced in accordance with A.Vengersky's method. Intraperitoneal administration of 4-pentenoic acid was performed once daily during seven days, the used dosage was 20mg/kg. The treatment of toxic hepatitis was carried with intraperitoneal administration of L-Carnitine 300mg/kg, Corvitine 100mg/kg and concurrent administration of these drugs. Monotherapy with Corvitin and L-Carnitin successfully improved liver function and equally decreased indicators of hepatocyte's cytolyses and increased levels of glucose and urea. The markers of cholestasis was slightly more improved during use of L-Carnitine. Simultaneous use of both drugs was effective in rats with Reye syndrome, indicators of liver damage normalized and herewith, no mortality outcome was observed. The most pronounced hepatoprotective effect of concurrent administration of L-Carnitine and Corvitin may be due to synergic action of these drugs and such regime can be recommended for correction of liver function during Reye syndrome.

Resveratrol protects against experimental induced Reye's syndrome by prohibition of oxidative stress and restoration of complex I activity.

This study was designed to investigate whether resveratrol could provide protection against Reye's syndrome induced by 4-pentenoic acid in Wistar albino rats. Compared with rats with untreated Reye's syndrome, 1 h pretreatment by low dose resveratrol (10 mg/kg by oral gavage) resulted in marked amelioration in liver functions in the form of significant decrease in serum transaminases (AST, ALT) and plasma ammonia levels, shortening of prothrombin time, and increase in serum albumin levels. In addition, resveratrol prohibited oxidative stress markers, as indicated by a significant increase in GSH and decrease in MDA, with restoration of complex I activity in liver tissues. The classical histopathological presentation in Reye's syndrome of microvesicular steatosis by light microscope and mitochondria distortion by electron microscope has been improved by resveratrol pretreatment. The efficient protection by resveratrol was determined by normalization in serum levels of AST and albumin, as well as complex I activity, GSH, and MDA. In conclusion, pretreatment by resveratrol in low doses could protect against Reye's syndrome partially via prohibition of oxidative stress and restoration of complex I activity. This may provide the opportunity to reconsider aspirin therapy for infants and young children. However, the verification of such results in clinical practice remains a challenge.

Pharmacogenetic Analysis of an 8-Year Old Girl with Reye Syndrome Associated with Use of Naproxen.

BACKGROUND Reye syndrome is a rare, yet potentially life-threatening disease characterized by acute encephalopathy and hepatic failure. This report presents the case of an 8-year-old girl with Reye syndrome and seizures after the use of naproxen. CASE REPORT An 8-year-old girl experienced a 3-day episode of fever and abdominal pain. After receiving naproxen (375 mg twice daily) starting from day -3, she exhibited hypotension, tonic seizure, and loss of consciousness (day 1). Physical examination and laboratory test results revealed acute kidney injury, metabolic acidosis, and elevated levels of lactate dehydrogenase (LDH), liver enzymes, and ferritin. On day 2, the maximum values of aspartate aminotransferase, alanine aminotransferase, LDH, creatinine, and ferritin were 955 U/L, 132 U/L, 8040 U/L, 2 mg/dL, and >40000 ug/L, respectively. She was given supportive care and recovered after 11 days (day 12), with normalization of kidney function and metabolic abnormalities. To identify possible genetic polymorphisms associated with the patient's symptoms, genotypes were tested using a drug metabolizing enzymes and transporters (DMET) gene chip. Among genes involved in the metabolism of naproxen, UGT1A6 (*1/*2) and UGT2B7 (*1/*2) resulted in possibly decreased function. Other results which may have had clinical significance included homozygote results for NAT2*6/*6 (rs1799930). CONCLUSIONS A rare case of Reye syndrome after administration of naproxen was presented in this case. A DMET gene chip was used to screen for possible genetic polymorphisms associated with Reye syndrome, but the result was inconclusive.

Linking drugs to obscure illnesses: lessons from pure red cell aplasia, nephrogenic systemic fibrosis, and Reye's syndrome. a report from the Southern Network on Adverse Reactions (SONAR).

Identification of serious adverse drug reactions (sADRS) associated with commonly used drugs can elude detection for years. Reye's syndrome (RS), nephrogenic systemic fibrosis (NSF), and pure red cell aplasia (PRCA) among chronic kidney disease (CKD) patients were recognized in 1951, 2000, and 1998, respectively. Reports associating these syndromes with aspirin, gadodiamide, and epoetin, were published 29, 6, and 4 years later, respectively. We obtained primary information from clinicians who identified causes of these sADRs and reviewed factors contributing to delayed identification of these toxicities. Overall, 3,500 aspirin-associated RS cases in the United States, 1,605 gadolinium-associated NSF cases, and 181 epoetin-associated PRCA cases were reported. Delays in FDA regulation of over-the- counter medications and administration of aspirin to children contributed to development of RS. For NSF, in 1996, the Danish Medicine Agency approved high-dose gadodiamide administration to chronic kidney disease (CKD) patients undergoing MR scans. Overall, 88 % of Danish NSF cases were from two hospitals and 97 % of United States' NSF cases were from 60 hospitals. These hospitals frequently administered high-doses of gadodiamide to CKD patients. Another factor was the decision to administer linear chelated contrast agents versus lower risk macrocyclic chelated agents. For PRCA, increased use of subcutaneous epoetin formulations to CKD patients, in part due to convenience and cost-savings considerations, and a European regulatory requirement requiring removal of albumin as a stabilizer, led to toxicity. Overall, 81, 13, and 17 years elapsed between drug introduction into practice and identification of a causal relationship for aspirin, erythropoietin, and gadodiamide, respectively. A substantial decline in new cases of these sADRs occurred within two years of identification of the offending drug. Clinicians should be vigilant for sADRs, even for frequently-prescribed pharmaceuticals, particularly in settings where formulation or regulatory changes have occurred, or when over-the-counter, off-label, or pediatric use is common.

Atypical Reye syndrome: three cases of a problem that pediatricians should consider and remember.

INTRODUCTION: Reye syndrome is a rare acquired metabolic disorder appearing almost always during childhood. Its aetiopathogenesis, although controversial, is partially understood. The classical disease is typically anticipated by a viral infection with 3-5 days of well-being before the onset of symptoms, while the biochemical explanation of the clinical picture is a mitochondrial metabolism disorder, which leads to a metabolic failure of different tissues, especially the liver. Hypothetically, an atypical response to the preceding viral infection may cause the syndrome and host genetic factors and different exogenous agents, such as toxic substances and drugs, may play a critical role in this process. Reye syndrome occurs with vomiting, liver dysfunction and acute encephalopathy, characterized by lack of inflammatory signs, but associated with increase of intracranial pressure and brain swelling. Moreover, renal and cardiac dysfunction can occur. Metabolic acidosis is always  detected, but diagnostic criteria are not specific. Therapeutic strategies are predominantly symptomatic, in order to manage the clinical and metabolic dysfunctions. CASE REPORTS: We describe three cases of children affected by Reye syndrome with some atypical features, characterized by no intake of potentially trigger substances, transient hematological changes and dissociation between hepatic metabolic impairment, severe electroencephalographic slowdown and slightly altered neurological examination. CONCLUSIONS: The syndrome prognosis is related to the stage of the syndrome and the rapidity and the adequateness of intensive care treatments. The analysis of the patients leads to a greater awareness of the difficult diagnosis of this not well completely known syndrome.

Reye syndrome and liver transplantation.

Reye syndrome is a rare, but severe and often fatal disease. The etiology of the classical Reye syndrome is unknown, but it is typically preceded by a viral infection with a free interval of three to five days. The main physiopathological hypothesis is a mitochondrial metabolism insult causing acute liver failure and encephalopathy. Survivors present serious neurological sequelae. The treatment of Reye syndrome is usually medical with intensive care management. Herein, we present the clinical case of a six-month-old baby diagnosed with Reye syndrome with a fulminant hepatitis, who was successfully liver transplanted with an auxiliary partial orthotopic liver transplantation.

Salicylate and mitochondrial injury in Reye's syndrome.

Electron microscopic and spectrophotometric studies showed that salicylate causes gross swelling of mitochondria in isotonic salt solutions. In overall morphology the salicylate-treated mitochondria resembled those from patients with Reye's syndrome. Salicylate analogs such as m-hydroxybenzoate, p-hydroxybenzoate, and benzoate did not exert this effect. The mitochondria deformed by salicylate tended to return to their original condensed form on removal of the drug.

FPIN's Clinical Inquiries. Aspirin use in children for fever or viral syndromes.

Aspirin should not be used to treat acute febrile viral illness in children. (Strength of Recommendation [SOR]: C, based on case-control studies). Although no causal link has been proven, data from case-control and historic cohort studies demonstrate an association between aspirin use and Reye syndrome. The risk of Reye syndrome decreases with age, becoming extremely rare by the late teenage years. Other nonsteroidal anti-inflammatory drugs are effective antipyretics and are not associated with the constellation of symptoms seen in Reye syndrome, which includes nausea, vomiting, headache, excitability, delirium, combativeness, and coma. Aspirin use in children younger than 19 years should be limited to diseases in which aspirin has a proven benefit, such as Kawasaki disease and the juvenile arthritides. (SOR: C, based on expert opinion).

Induction of omega-oxidation of monocarboxylic acids in rats by acetylsalicylic acid.

The accumulation of dicarboxylic acids, particularly long chain, is a prominent feature of Reye's syndrome and diseases of peroxisomal metabolism. We assessed the omega-oxidation of a spectrum of fatty acids in rats and asked whether pretreatment of rats with aspirin, which is known to predispose children to Reye's syndrome, would affect omega-oxidation of long chain fatty acids. We found that aspirin increased liver free fatty acids and increased the capacity for omega-oxidation three- to sevenfold. Omega-oxidation of long chain substrate was stimulated to a greater degree than medium chain substrate and was apparent within one day of treatment, at serum aspirin concentrations below the therapeutic range in humans. The apparent Km for lauric acid was 0.9 microM and 12 microM for palmitate. We also found a difference in the storage stability of activity toward medium and long chain substrate. Saturating concentrations of palmitate had no effect on the formation of dodecanedioic acid, whereas laurate decreased but never eliminated the omega-oxidation of palmitate. 97% of the total laurate omega-oxidative activity recovered was found in the microsomes, but 32% of palmitate omega-oxidative activity was present in the cytosol. These results demonstrate that aspirin is a potent stimulator of omega-oxidation and suggest that there may be multiple enzymes for omega-oxidation with overlapping substrate specificity.

Aspirin and Reye syndrome: a review of the evidence.

Reye syndrome is an extremely rare but severe and often fatal disease. Death occurs in about 30-40% of cases from brainstem dysfunction. The disease typically is preceded by a viral infection with an intermediate disease-free interval of 3-5 days. The biochemical explanation for Reye-like symptoms is a generalized disturbance in mitochondrial metabolism, eventually resulting in metabolic failure in the liver and other tissues. The etiology of 'classical' Reye syndrome is unknown. Hypothetically, the syndrome may result from an unusual response to the preceding viral infection, which is determined by host genetic factors but can be modified by a variety of exogenous agents. Thus, several infections and diseases might present clinically with Reye-like symptoms. Exogenous agents involve a number of toxins, drugs (including aspirin [acetylsalicylic acid]), and other chemicals. The 'rise and fall' in the incidence of Reye syndrome is still poorly understood and unexplained. With a few exceptions, there were probably no new Reye-like diseases reported during the last 10 years that could not be explained by an inherited disorder of metabolism or a misdiagnosis. This may reflect scientific progress in the better understanding of cellular and molecular dysfunctions as disease-determining factors. Alternatively, the immune response to and the virulence of a virus might have changed by alteration of its genetic code. The suggestion of a defined cause-effect relationship between aspirin intake and Reye syndrome in children is not supported by sufficient facts. Clearly, no drug treatment is without side effects. Thus, a balanced view of whether treatment with a certain drug is justified in terms of the benefit/risk ratio is always necessary. Aspirin is no exception.

Methyl bromide intoxication: neurologic features, including simulation of Reye syndrome.

Three family members intoxicated with methyl bromide presented with a variety of neuropsychiatric manifestations including coma, severe status epilepticus, hyporeflexia, and acute psychosis. The simulation of Reye syndrome in the child emphasizes the need for careful toxicologic screening of all children presenting with this syndrome. The initial diagnostic difficulty encountered in these cases emphasizes the need for heightened awareness of the toxic chemicals used in local industries and the clinical manifestations of their intoxication.

Short chain fatty acid-induced central hyperventilation in rabbits.

The short chain fatty acid sodium octanoate was infused into rabbits as an 0.2 M solution over 4 hours, resulting in blood and brain levels of 200 to 700 mumoles per liter. During the infusion, animals exhibited marked hyperventilation, resulting in a mild respiratory alkalosis. Octanoate infusion also resulted in significant hyperammonemia and lactic acidemia. Saline-treated control animals demonstrated no clinical or chemical abnormalities. Several short chain fatty acids, including octanoate, are increased in the plasma of patients with hepatic encephalopathies and Reye syndrome. The present study suggests that short chain fatty acids may be endogenous toxins in these clinical disorders. In particular, the central hyperventilation in these conditions may be due to the neurotoxic effect of short chain fatty acids.

Use of antipyretic analgesics in the pediatric patient.

Fever and pain are the most common issues in pediatric patient management. Acetaminophen, aspirin, and dipyrone are the most commonly used drugs and are equivalent in their efficacy. Dipyrone, used in many parts of the world, but not in the United States, is an effective agent; however, it has been implicated in producing agranulocytosis and anaphylactic shock. The salicylates have anti-inflammatory effects making them appropriate for the treatment of patients with juvenile rheumatoid arthritis, but they are gastric irritants, may impair clotting, and, because of saturable kinetics, may lead to accumulation and toxicity. Acetaminophen is an effective antipyretic and analgesic with few side effects that is toxic only in massive overdose.

Reye's syndrome and salicylate use.

During an outbreak of influenza A, seven patients with Reye's syndrome and 16 ill classmate control subjects were evaluated for characteristics of the patients' prodromal illness and the control subjects illness and for medication usage. Patients during the prodrome and control subjects had similar rates of sore throat, coryza, cough, headache, and gastrointestinal complaints except for documented fever which occurred significantly more often in patients than in control subjects (P = .05). While medications which did not contain salicylate were taken as frequently by patients as control subjects, patients took more salicylate-containing medications than did control children (P < .01). All seven patients took salicylate whereas only eight of 16 control subjects did so (P < .05). Patients took larger doses of salicylate than did the entire control group (P < .01). When the eight control subjects who took salicylate were compared with the patients, the patients still tended to take larger doses (P = .08). Patients with fever took salicylate more frequently than control subjects with fever (P < .01). In addition, salicylate consumption was correlated with severity of Reye's syndrome (P < .05). It is postulated that salicylate, operating in a dose-dependent manner, possibly potentiated by fever, represents a primary causative agent of Reye's syndrome.