[The Reye syndrome]

The Reye syndrome is a complex disease that remains little-known despite its severity. It can occur in children of all ages, and is often fatal, while surviving children often display neurological damage. The therapy is symptomatic and supportive. The diagnosis of Reye's syndrome is not straightforward, as the symptoms are very diverse. The causes of the disease are moreover still unclear, and, after many years of discussion and research, it can still not be proved irrefutably whether administration of acetylsalicylic acid to children suffering from viral infections is a factor in the development of Reye's 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.

Reye syndrome: a case report with review of literature

Here we describe a case of Reye syndrome diagnosed at postmortem liver biopsy of a three-year old girl who presented with vomiting, low grade fever for three days and loss of consciousness for 18 hours. Clinically, the differential diagnoses were meningitis, encephalitis and septicemia. No history of past illness or any drug ingestion including aspirin were present. Laboratory investigations indicated a diagnosis of Reye syndrome. The child was given supportive treatment but died after two days of admission and postmortem needle-biopsy of the liver showed microvesicular steatosis consistent with Reye syndrome.

The thalamus and midbrain in Reye syndrome

A previously healthy 5 1/2-year-old male had Reye syndrome. He presented in coma with apnea 1 week after a viral infection and following 2 days of vomiting and progressive obtundation. He was in coma with dystonic posturing and intact brainstem function. Laboratory evaluation revealed initial hypoglycemia, and markedly elevated liver enzymes, prolonged clotting times, and elevated ammonia levels. No underlying metabolic disorder was present, and the patient completely recovered. On a modified diffusion-weighted image magnetic resonance imaging scan, restriction of diffusion in the thalamus and midbrain was observed. While abnormalities of the thalamus and midbrain have previously been reported, this is the first report of diffusion-weighted imaging indicating early impairment of water diffusion, a finding more commonly observed with stroke.

Metabolic stroke in three years old boy as the consequence of metabolic derangement. A case report of recidiving Reye's-like syndrome

Three years old boy with developmental renal dysplasia was hit as newborn child by attack of cerebral edema with metabolic disturbances (hypoglycemia, hypophosphatemia, ketoacidosis and with hypocoagulation state) and was classified as child at risk in the pediatric evidence. In the third year of the age he went through nephrectomy and after the operation, the similar metabolic disturbances occurred (hypoglycemia, ketoacidosis, derangement of the metabolic situation). Cerebral edema and the metabolic stroke developed. Reye's-like syndrome was considered and serious functional disturbances of basal ganglia and brain-stem structure were observed.

[Refractory epilepsy status in Reye's syndrome in an adult. A case report]

INTRODUCTION

Reye s syndrome (RS) is a potentially fatal disease described in 1963 by Reye, Morgan and Baral as an acute encephalopathy associated with a lipid degeneration of the liver. It affects children of all ages, with a peak incidence between 5 and 15 years old, but on rare occasions it can also affect adults. Its aetiology is not known, but is has been linked with viral infections and with the ingestion of salicylates. Its occurrence in adults is not at all frequent and only 27 cases have been recorded in the literature.

CASE REPORT

We report the case of a 33 year old primiparous patient who, during lactation, began suffering from epilepsy and a lowered level consciousness in the course of an infection of the pharynx and tonsils, and died on the 12th day after admission to the ICU. Anamnesis revealed she had taken ASA for the first time in her life, which guided diagnosis, and this was confirmed post mortem in the anatomopathological examination.

CONCLUSION

RS in adults occurs only rarely but should be a part of the differentiating diagnosis of any encephalopathy of unknown origin and especially of the epileptic status of an adult, above all if there is a history of ingestion of salicylates, previous viral infection and vomiting.

Mortality in dioxin-exposed mice infected with influenza: mitochondrial toxicity (reye's-like syndrome) versus enhanced inflammation as the mode of action

Increased mortality following influenza A infection was reported in B6C3F1 mice exposed to a low (0.01 micro g/kg) dose of dioxin. However, mortality was not associated with increased viral load and antibody titers to the virus were not decreased at doses of TCDD < or = 10 micro g/kg, suggesting that viral overgrowth, secondary to immunosuppression, was not the proximate cause of death. We tested the hypothesis that mitochondrial toxicity and dysfunction, similar to Reye's syndrome (RS) in humans, is responsible for increased mortality in dioxin-exposed, infected B6C3F1 female mice, based on similarities in the biochemical and immunological events that occur in RS and in TCDD-exposed animals. Endpoints were also included to test the hypothesis that increased pulmonary inflammation following dioxin exposure, in the absence of mitochondrial toxicity, was associated with increased mortality. Dose-related effects of TCDD alone, infection with influenza A alone, and combined TCDD exposure/influenza infection were evaluated. Mice were given a single ip injection of 0, 0.001, 0.01, 0.1, or 1.0 micro g TCDD/kg, 7 days before infection by intranasal instillation of an estimated LD(10-20) of influenza A Hong Kong/8/68 (H3N2) and were terminated 1, 7, and 10 days after infection. Serum, bronchoalveolar lavage fluid (BALF), and lung tissue were collected for various measurements, including clinical chemistries, cell counts, cytokine analysis, and viral titers. Exposure to < or = 1.0 micro g TCDD/kg did not increase mortality; virus titers were similar at all doses of TCDD and there was no dioxin-related effect on serum NH(3) or glucose concentrations, two prominent indicators of the altered mitochondrial oxidative metabolism typically observed in RS. A study was therefore conducted over a wider range of TCDD doses. A single injection of 0, 0.025, 0.5, or 10 micro g TCDD/kg preceded infection by 7 days; subgroups of noninfected control and highest dose group (10 micro g TCDD/kg) mice were also evaluated for biochemical and immunological endpoints on the equivalent of infection day 4 to provide baseline data. Five days after infection the same endpoints described above were evaluated. The 10 micro g TCDD/kg dose increased mortality, but once again did not increase virus titer; as in previous experiments, serum biochemistry endpoints did not support mitochondrial dysfunction. These results suggest that RS is an unlikely explanation for increased influenza mortality in TCDD-exposed mice. Rather, constituents in BALF implicate increased pulmonary inflammation as the mode of TCDD action.

[Severe Reye syndrome: report of 14 cases managed in a pediatric intensive care unit over 11 years]

Idiopathic Reye syndrome is a rare disease revealed by unexplained encephalopathy and microvesicular liver steatosis. Some clinical and epidemiological studies mainly performed in English speaking countries questioned the reality of Reye syndrome because numerous know inherited metabolic diseases, and some of them unrecognized, could mimick this disorder. We focused in our study on severe forms of Reye syndrome admitted to a pediatric intensive care unit.

METHODS

Retrospective study over the last eleven years (1991-2001) included all the pediatric patients admitted to our tertiary referral center with the classical American Reye syndrome criteria (e.g. CDC). Extensive metabolic screening was performed in all cases, except for the ultimately dead patients.

RESULT

Fourteen patients (mean age 52 months) were included. Fever always occurred before their admission and aspirin (n = 12) or acetaminophen (n = 7) was prescribed. Median Glasgow scale was 7 on admission. Mean amoniac plasma level was 320 mumol/L and alanine-aminotransferase peak plasma level 1475 +/- 1387 IU/L. Mechanical ventilation was started in ten children and six of them underwent continuous venovenous hemofiltration. Three patients ultimately died and 11 survived with a mean five years follow-up without relapses or neurological impairment. Any of them demonstrated inherited metabolic disease except for one infant with hereditary fructose intolerance.

CONCLUSION

Unlike widespread opinion, severe Reye syndrome without identified metabolic disorders seems to not disappear in our country. Reye syndrome remains a potentially life threatening disease and raises for aggressive treatment of brain edema. If aspirin and Reye syndrome association are not formally documented in France, cautiousness must be kept in mind and all the aspirin adverse effects notifications should be addressed to the public drugs survey network.

Association of varicella, myocarditis, and congestive cardiomyopathy

A retrospective study of children dying with active varicella revealed 11 of 17 cases who had unsuspected interstitial myocarditis at the time of their death. In addition, a prospective study of 6 children, consecutively admitted to the hospital with active varicella, were evaluated for evidence of cardiac dysfunction by echocardiography, ECG, and serum enzyme levels. All 6 children had Reye's syndrome in association with active varicella. Evidence of myocardial involvement, consistent with acute congestive cardiomyopathy, was documented in 4 of the 6 children. This study suggests that the heart is commonly involved in varicella infections and that cardiac involvement should be considered in children with this disease.

Visualization of mitochondria with green fluorescent protein in cultured fibroblasts from patients with mitochondrial diseases

cDNAs for green fluorescent protein (GFP) and for a GFP fusion protein containing the presequence of human ornithine transcarbamylase (pOTC-GFP) were transfected into cultured human fibroblasts. GFP cDNA gave diffuse fluorescence throughout the cytoplasm and the nucleus, whereas pOTC-GFP cDNA gave mitochondria-associated fluorescence. Fluorescent mitochondrial structures could be classified into five patterns: thread-like mitochondria, fine thread-like ones, rod-like ones, granular ones, and granular ones with weak cytosolic fluorescence. pOTC-GFP mutants resulted in a loss of mitochondrial fluorescence and an appearance of weak fluorescence throughout the cytoplasm. pOTC-GFP cDNA was transfected into fibroblasts from patients with various mitochondrial diseases. Higher ratios of fibroblasts with granular mitochondria and those with fine thread-like ones were observed in a patient with Reye's syndrome and a patient with Kearns-Sayre syndrome. Weak cytosolic fluorescence was sometimes observed in fibroblasts from these patients. This method will be useful to analyze mitochondrial structural alterations and disorders of mitochondrial protein import.

The mitochondrial permeability transition in toxic, hypoxic and reperfusion injury

Opening of a non-specific, high conductance permeability transition pore or megachannel in the inner mitochondrial membrane causes onset of the mitochondrial permeability transition, which is characterized by mitochondrial swelling, depolarization and uncoupling. Inducers of the permeability transition include Ca2+, oxidant stress and a permissive pH greater than 7.0. Blockers include cyclosporin A, trifluoperazine and pH < 7. Using laser scanning confocal microscopy, we developed techniques to visualize onset of the mitochondrial permeability transition in situ in living cells. In untreated cells, the permeability transition pore is continuously closed and does not 'flicker' open. By contrast, the pore opens in liver and heart cells after exposure to oxidant chemicals, calcium ionophore, hypoxia and ischemia/reperfusion, causing mitochondrial uncoupling and aggravation of ATP depletion. In injury to hepatocytes from tert-butylhydroperoxide, an analog of lipid hydroperoxides generated during oxidative stress, onset of the mitochondrial permeability transition is preceded by oxidation of mitochondrial pyridine nucleotides, mitochondrial generation of oxygen radicals and an increase of mitochondrial Ca2+, all inducers of the mitochondrial permeability transition. In ischemia, the acidosis of anaerobic metabolism protects strongly against cell death. During reperfusion, recovery of pH to normal levels is a stress that actually precipitates cell killing. Onset of the mitochondrial permeability transition may be responsible, in part, for this pH-dependent injury, or pH paradox. The mitochondrial permeability transition may also be responsible for a variety of pathological phenomena. In particular, the mitochondrial permeability transition may underlie Reye's syndrome and Reye's-like drug toxicities. In conclusion, multiple mechanisms contribute to cell injury after hypoxia, ischemia/reperfusion and toxic chemicals, but a common final pathway leading to acute cellular necrosis may be ATP depletion after mitochondrial failure. One important mechanism causing mitochondrial failure is the mitochondrial permeability transition, which both uncouples oxidative phosphorylation and accelerates ATP hydrolysis. Interventions that block this pH-dependent phenomenon protect against onset of cell death.

[An autopsy case of the Reye's syndrome]

A case of sudden unexpected natural death in a 6-year-old girl was reported. She was found in dead with vomiting on her bed in the morning on 24. December. Autopsy did not reveal any injuries and abnormalities on her appearance. Small amount of light yellowish mucus in her nose, trachea and bronchus was found. Brain was slightly edematous (1395 g in weight). Liver was 750 g in weight and focal yellowish lesions were observed on its cut surfaces. Microscopically fatty degeneration (granulous fatty deposits) was observed in hepatocytes. Immunohistochemical staining of mitochondria in heart showed no staining microscopically, and degeneration and breakdown of mitochondria were found electromicroscopically. From the results of autopsy and histopathological findings, her cause of death was diagnosed as the Reye's syndrome.

Metabolic function and liver histopathology in Reye-like illnesses

Forty children with Reye syndrome (RS) or Reye-like illnesses were investigated to elucidate the underlying aetiologies. Extensive biochemical studies including patterns of organic acids and amino acids, liver histopathology, and, if available, a DNA approach were performed. In addition to classical RS (n = 10), the causes of Reye-like conditions included hereditary organic acidaemias (n = 13), urea cycle defects (n = 4), mitochondrial disorders (n = 3), fulminant hepatitis (n = 2), tyrosinaemia (n = 1), valproate-associated hepatotoxicity (n = 1), and other non-specific generalized organic acid disorders (n = 6). It is important to collect specimens when encephalopathy with liver dysfunction of unknown causes is noted. When the underlying inherited metabolic disorders are confirmed, the prevention of the recurrence by adequate diet control and medications, and genetic counselling become possible.

The changing clinical pattern of Reye's syndrome 1982-1990

OBJECTIVE

To describe trends in the clinical pattern of Reye's syndrome in the British Isles between 1982 and 1990; and to determine the relation between any changes and the June 1986 warnings against the use of aspirin in children.

DESIGN

Development, and application to reported cases, of a scoring system designed such that patients showing the typical clinical and pathological features of 'classical' Reye's syndrome scored highly. The relations between 'Reye scores' and a number of explanatory variables were explored using multivariable analysis.

SETTING

British Isles.

SUBJECTS

445 cases fulfilling the Reye's syndrome case definition reported to the surveillance scheme between January 1982 and December 1990.

MAIN OUTCOME MEASURE

Individual 'Reye score'.

RESULTS

Cases with high scores were more likely to have occurred in the 4 1/2 year period before June 1986 compared with the subsequent period (p < 0.006). Numbers of cases in the low and intermediate score categories declined by about 50% after June 1986, whereas those in the high category fell by 79%. High scorers were more likely to have received aspirin (p < 0.0001) and were older than intermediate and low scorers (p < 0.008). No relation was identified between score and season of onset.

CONCLUSIONS

The decline in Reye's syndrome after the aspirin warnings cannot be explained entirely, as has been proposed, by improved diagnosis of 'Reye-like' inherited metabolic and other disorders: this would not account for the greater decline of the high scoring subgroup which also contained those cases most likely to resemble 'classical' Reye's syndrome and to have received aspirin. This study provides further evidence for the role of aspirin in a subset of cases meeting the standard diagnostic criteria for Reye's syndrome and supports the need to consider this disorder as a heterogeneous group of conditions including Reye-like inherited metabolic disorders.

Arrhythmias and ischemia-like ECG changes in Reye's syndrome

We report a fatal case of a child presenting Reye's syndrome associated with a variety of arrhythmias and ischemia-like ST-T ECG changes. At autopsy, fatty infiltration and patchy myocytolysis were detected in sections of the heart. This case report emphasizes cardiac involvement in Reye's syndrome and the possible mechanisms of arrhythmias in this disease.

Reye syndrome model in rats: protection against liver abnormalities by L-carnitine and acetyl-L-carnitine

The effects of L-carnitine (LCn) and acetyl-L-carnitine (AcLCn) were assessed on the liver alterations observed in Kilpatrick's model of Reye syndrome in rats; fasted rats were given lipopolysaccharide (LPS), 0.2 mg/kg i.p., 12 hr before they were sacrificed, plus acetylsalicylic acid (ASA), 50 mg/kg i.p., 11 hr before sacrifice; LCn or AcLCn were given twice, 500 mg/kg orally, 12 and 2 hr before sacrifice. LPS+ASA-treated rats showed a dramatic decrease of hepatic ketone bodies and acetyl-CoA and an increase of isobutyryl-CoA, isovaleryl-CoA and succinyl-CoA. Electron microscopy of LPS+ASA-treated rat liver showed a slight but significant alteration in mitochondrial inner structure. Because impairment of mitochondrial function in RS is associated with swelling, we investigated whether the microviscosity of mitochondrial lipids and the cholesterol-phospholipid ratio (CHOL/PL), were involved in the RS model used. Mitochondria from LPS+ASA-treated rats showed a decrease in lipid microviscosity, in CHOL/PL ratio and in CHOL/PL ratio of both inner and outer membrane fractions; these alterations suggested a general increase in membrane fluidity. LCn and AcLCn reversed the morphological alterations in mitochondria after LPS+ASA, observed by electron microscopy, the decrease in KB and the toxic increase in short-chain acyl-CoAs; AcLCn only reversed the decrease in acetyl-CoA. LCn and AcLCn prevented mitochondrial lipid alterations mainly in the inner membrane fraction.(ABSTRACT TRUNCATED AT 250 WORDS)

[Clinical-instrumental dissociation in a case of Reye's syndrome]

We report the case of a boy 5 years old we admitted to our PICU with signs of impending hepatic failure (hypertransaminasemia, hyperammonemia, prolonged PT) following mild upper respiratory infection and irrepressible vomiting. We observed no neurological abnormalities excepting slight lethargy; on the contrary, EEG findings showed severe diffuse slowing and high-voltage Delta activity. Our diagnosis of Reye's syndrome was later confirmed by liver biopsy. Clinical and electrophysiological signs recovered after 48-72 hours and no explication was found for this anomalous Reye's syndrome presentation. Further studies are needed for understanding the basis of neurological involvement of stage I Reye's syndrome.

Inhibition of beta-oxidation by 3-mercaptopropionic acid produces features of Reye's syndrome in perfused rat liver

BACKGROUND/AIMS

The cause of Reye's syndrome has not been completely defined. The rate of ketogenesis in the liver is a key determinant of, and reciprocally related to, triglyceride secretion. In the present study, 3-mercaptopropionic acid (MPA), a known inhibitor of mitochondrial long-chain acyl coenzyme A (CoA) dehydrogenase, was used to investigate the relationship between ketone body production, triglyceride secretion, and triglyceride accumulation in perfused rat liver.

METHODS

Livers from fasted rats were perfused 225 minutes with or without MPA in the presence of [1-14C]oleic acid. Morphology was studied by light and electron microscopy.

RESULTS

Inhibition of fatty acid oxidation by the liver with MPA resulted in a decrease in ketone body production. Treatment with MPA caused an accumulation of small-droplet triglycerides in liver, whereas the net secretion of triglyceride ceased after an initial period of increased secretion with continued decreased ketogenesis. At the end of the perfusion period, mitochondria in the MPA group appeared to be damaged.

CONCLUSIONS

The rates of both ketogenesis and triglyceride secretion by the liver appear to be the major determinants of hepatic triglyceride content. In addition, the MPA-mediated biochemical and morphological findings are quite similar to those of Reye's syndrome.

[Reye's syndrome and hemophagocytic histiocytosis in a 16-month-old boy: is there a possible common etiopathogenetic basis?]

The Authors report a case of Reye's syndrome associated with an hemophagocytic histiocytosis in a 16-month-old baby. The vaccination against measles, mumps and rubella administrated 15 days before the onset of symptoms is suggested as the etiologic factor of both diseases. The Authors believe that the vaccine, composed of alive viruses was responsible of immunodepression and, as a common viral infection, of Reye's syndrome and hemophagocytic histiocytosis in the child constitutionally predisposed.

[A case of clinical Reye syndrome with symmetrical abnormal signal areas in the pons and thalami by MRI]

We report a two-year-old boy with clinical Reye syndrome. Brain CT disclosed symmetrical low-density areas in the pons and thalami, a part of which was recognized as being of high-intensity on both T1 and T2 weighted MRI. These lesions were suspected of being caused by vascular involvement, since the methemoglobin induced by bleeding may have contributed to the high-intensity regions. The lesions gradually disappeared within four months after the onset, and clinical symptoms also improved markedly without serious neurologic impairment. This case was characterized by the marked improvement in neurological and radiological findings in spite of the serious neurological involvement at onset.

Hyperplasia of pulmonary arterial media in infantile familial pulmonary hypertension associated with severe metabolic acidosis

Two female siblings, offspring of consanguinous parents, died at 10 and 12 wk of age following short illnesses characterized clinically by hypoxia and severe metabolic acidosis. Cardiac catheterization confirmed severe pulmonary hypertension in the second infant, who survived 6 wk after onset of symptoms and 4 wk after admission to hospital; extensive investigations failed to identify any inborn metabolic error. At autopsy, small pulmonary arteries/arterioles in both cases showed marked medial thickening due to smooth muscle hyperplasia; concentric intimal fibrosis was present focally in the older infant. Compared morphometrically with small pulmonary arteries in 20 infantile controls who died of Reye's syndrome (n = 8), a Reye's-like illness (n = 5) or an identified metabolic error associated with metabolic acidosis (n = 7), intraacinar pulmonary arteries in both cases, were significantly more numerous and had a significantly greater relative medial thickness. We suggest that an autosomal recessive gene caused or potentiated the pulmonary medial hyperplasia. The latter finding, compared with medial hypertrophy, is rarely described as the morphologic basis of pulmonary hypertension, and its occurrence may be restricted to early infancy. In this family, the relationship between hypertensive pulmonary arteriopathy and severe metabolic acidosis remains speculative.

[Acute encephalopathy associated with centrilobular necrosis of liver mimicking Reye's syndrome--report of two cases]

Recent experience suggests that a diagnosis of Reye's syndrome based on clinical and biochemical grounds alone may be unreliable. Two patients are presented here, whose clinical manifestation suggested Reye's syndrome. The biochemistry data were also compatible with Reye's syndrome except that the levels of serum AST and ALT were significantly higher with normal serum ammonia level. Blood amino acid and urinary organic acid assay all showed negative findings. Histological findings of the liver showed marked centrilobular necrosis rather than fatty metamorphosis. The muscle biopsies did not show lipid accumulation in the muscle fibers as well. The findings in our patients suggested that a confirmatory diagnosis of Reye's syndrome requires a characteristic pathological findings of the liver in order to differentiate Reye's syndrome from Reye-like syndrome, especially acute encephalopathy associated with centrilobular necrosis of the liver.

Symmetrical thalamic lesions on CT in influenza A virus infection presenting with or without Reye syndrome

In Reye encephalopathy, diffuse brain swelling is a well known CT finding, but focal CT lesions have not been documented. We report 2 children with Reye encephalopathy and 2 children with non-Reye encephalopathy both associated with influenza A virus infection in whom symmetrical low density lesions of the thalamus and brainstem were detected on CT. These symmetrical low density lesions were present in the acute phase and decreased in size within a few weeks in all, and are still seen 2 years later as clearly defined small round areas in 3 surviving patients. Paired influenza A virus titers in blood showed 4-fold or more increase in all. Myelin basic protein (MBP) in CSF was increased in 2 of the 3 subjects studied. Liver biopsy showed diffuse lipid droplet infiltration in 2, focal infiltration in 1, and normal morphology in 1. The above data suggest that the symmetrical low density lesions were associated with influenza A virus infection, most likely consisting of edema, demyelination, and necrosis. We suspect that there is a continuum of Reye syndrome and virus-associated encephalopathy with significant overlap.

[Neuropathological analysis of 8 cases of clinically diagnosed Reye syndrome]

Authors discuss the possible etiopathogenesis of Reye syndrome (RS) on the base of eight own cases presented in this paper and others previously described. The febrile infection was observed on the beginning of the disease in all actually analysed cases and was followed by symptoms of acute damage of liver and brain. The central nervous system lesions present the changes increasing with time from brain oedema to the necrosis of nerve tissue. The oedematous changes could be recognized as a principal cause of unconsciousness and even of coma in RS. When the etiology of RS remain unknown the clinico-pathological observations of such cases incline to formulate three questions: Is an genetically conditioned background necessary which facilitate toxic or infectious factors to induce the RS? Is the etiology of RS only genetically conditioned? Is an specific viral infection the cause of RS?

Reye's syndrome. A diagnosis occasionally first made at medicolegal autopsy

Reye's syndrome, a condition characterized pathologically by cerebral edema and fatty change of the liver, has been described extensively in the medical literature as a disease manifested clinically by encephalopathy and coma. This is a report of five cases of Reye's syndrome occurring as sudden, unexpected deaths outside of the hospital. In each of these cases, there is a vague history of a previous viral illness. A history of aspirin intake is inconstant. Each child either had no significant past illnesses or there was a history of repeated upper respiratory infections. The classic progression of signs and symptoms usually described for Reye's syndrome, where vomiting usually precedes encephalopathy and coma, was not present in any of the cases. Results of autopsies showed the characteristic findings for Reye's syndrome, and additional tests showed no other explanation for the deaths. This manifestation of the disease is seldom described in medical literature, but it may be encountered occasionally by the medical examiner.

Reye's syndrome in Bangalore

One hundred and twenty four cases of Reye's syndrome admitted to Vanivilas Children's Hospital, Bangalore were investigated. Clinical, biochemical and epidemiological details were obtained. The median age was five years, with no difference in sex ratio. This disease was frequent in winter months. Cases clustered in certain congested localities of the city among lower socio economic strata. Aspirin and varicella could not be associated as preceding factors. The clinical and biochemical features of the patients were suggestive of Reye's syndrome. Histopathological evaluation was done in 104 liver biopsy specimens. Virological studies for influenza and arbovirus were negative. Mortality was high (78%).

Influenza A virus in the mouse: hepatic and cerebral lesions in a Reye's syndrome-like illness

To develop an animal model of Reye's syndrome using a virus associated with the human disease, mice were intravenously inoculated with influenza A/PR8 virus (LD50 4000 haemagglutinin units). One to 3 days later the mice developed lethargy, seizures, coma and death. The cerebrospinal fluid cell count was normal. Serum aspartate aminotransferase levels increased 24-fold. Diffuse microvesicular fatty metamorphosis along with multiple small foci of necrosis developed in the liver. Influenza virus-like particles were seen by electron microscopy in the liver, primarily in areas of liver necrosis, but were not seen in the brain. Cerebral oedema without inflammation developed in the brain. Limited viral replication occurred within the liver. Influenza viral antigens were seen in 5-20% of hepatocytes from both necrotic and non-necrotic areas as well as in brain endothelial cells. Many of the clinical, biochemical and pathologic features of the mouse illness resemble those seen in Reye's syndrome. However, this model differs from the human disease in that focal areas of liver necrosis occurred along with limited complete viral replication in liver.

Prevention of 4-pentenoic acid-induced liver injury in rats by 16,16-dimethyl PGE2

16,16-Dimethyl PGE2 (dmPGE2) is known to protect against cellular damage in various tissues. Histological and biochemical approaches were used to examine the effect of this prostaglandin on hepatocellular damage in an experimental Reye's syndrome model produced in rats by 4-pentenoic acid. Chronic intraperitoneal administration of 4-pentenoic acid induced an accumulation of fatty droplets throughout the hepatic lobules along with mitochondrial abnormalities including swelling, disappearance of christae, and heterogeneity of matrix. These abnormalities were more intense in the marginal zone and successively decreased nearer to the central vein. Such hepatic abnormalities were markedly reduced by the combined administration of dmPGE2 with 4-pentenoic acid. Biochemical examination confirmed that dmPGE2 was able to inhibit the accumulation of hepatic triglyceride seen after the treatment with 4-pentenoic acid alone. These results indicated that dmPGE2 can prevent characteristic hepatocellular damage in this experimental Reye's syndrome model, suggesting that the involvement of prostaglandins should be taken into account in discussing the etiology and management of this syndrome.

Reye's syndrome associated with acute myocarditis and fatal circulatory failure

We describe an eight-month-old infant who had an unusually fulminant and fatal course of Reye's syndrome. The patient died 36 hours after admission because of irreversible circulatory failure not associated with clinical symptoms of increased intracranial pressure or cerebral herniation. Autopsy revealed the pathognomonic fatty degeneration of the liver and heart of Reye's syndrome, but the brain was normal. In addition, a marked inflammatory infiltration of the myocardium was also observed, which indicated that acute myocarditis had been the preceding underlying disease. This case report emphasizes the fact that the viral prodrome preceding Reye's syndrome may not be as benign as often observed with influenza and varicella. Acute myocarditis and Reye's syndrome are also a combination which may result in fatal cardiovascular collapse.

Murine adenovirus infection of SCID mice induces hepatic lesions that resemble human Reye syndrome

Murine adenovirus type 1 (MAV-1) infection of CB-17 SCID mice (which are homozygous for the severe combined immunodeficiency mutation) induces hepatic histopathologic and ultrastructural features that are strikingly similar to human Reye syndrome. Gross pathologic examination of MAV-1-infected mice revealed only pale yellow liver tissue. Histopathologic studies of tissue from MAV-1-infected mice revealed diffuse hepatic injury manifested by microvesicular fatty degenerative changes of hepatocytes and electron microscopic evidence of focal mitochondrial swelling with disruption of cristae and depletion of glycogen. Serum aminotransferase activities increased markedly in the infected animals; however, plasma ammonia levels were not elevated at the times assayed. Although all mice infected with MAV-1 died, neutralizing anti-MAV-1 monoclonal antibodies provided a dose-dependent delay in the appearance of clinical disease and hepatic histopathologic findings. Other findings included rare viral inclusions with only minimal inflammation in spleen, adrenal, and liver of infected mice. Our findings indicate that MAV-1 infection of SCID mice may provide important insights into the pathogenesis of the hepatic lesions of Reye syndrome.

Liver histopathology in clinical Reye syndrome

Analysis of the liver histopathology in 19 children with clinical Reye syndrome (RS) revealed that nine had diffuse panlobular steatosis, one giant cell hepatitis, one a mild choledochal cyst with inflammation, two multifocal spotty necrosis and one multiple centrilobular necrosis, the other five being normal. Four of the nine patients with diffuse panlobular steatosis showed microvesicular fatty droplets with central nuclei, which was consistent with findings characteristic for typical RS. Two cases showed a periportal area dominant macrovesicular fatty change, which was highly suggestive for metabolic disorder. In the other three cases, the findings were so variable in terms of the size of lipid droplets and the location of nuclei in hepatocytes that it was not possible to provide any clue for defining a diagnosis. These results confirmed the legitimacy of the diagnostic criteria of RS which included a liver biopsy as one of the mandatory conditions. They also indicated that RS-mimicking clinical pictures can be presented by miscellaneous conditions in which liver histology does not necessarily helpful in establishing definite diagnosis.

Medium-chain acyl CoA dehydrogenase deficiency: electron microscopic differentiation from Reye syndrome

Inborn errors involving the oxidative metabolism of fatty acids may present clinically with a Reye syndrome-like picture. This case report of a patient with medium-chain acyl CoA dehydrogenase (MCAD) deficiency illustrates that electron microscopy may help to differentiate this disorder from Reye syndrome even if a liver biopsy is performed in a patient who recovered from an acute metabolic decompensation. Together with this case, a review of the few reports in the literature of pathological findings in MCAD deficiency is given. Changes uncharacteristic for Reye syndrome are a large-droplet steatosis and the presence of distinctive mitochondrial abnormalities on electron microscopy. The detection of an electron dense mitochondrial matrix and a widened space of inner mitochondrial membranes rules out Reye syndrome and is suggestive of a disorder of mitochondrial fatty acid oxidation.

Liver fatty acid-binding protein in two cases of human lipid storage

FABPs in the various tissues play an important role in the intracellular fatty acid transport and metabolism. Reye's syndrome (RS) and multisystemic lipid storage (MLS) are human disorders characterized by a disturbance of lipid metabolism of unknown etiology. We investigated for the first time L-FABP in these two conditions. Affinity purified antibodies against chicken L-FABP were raised in rabbits, and found to cross-react specifically with partially purified human L-FABP. L-FABP content in liver samples of two patients with RS and MLS was investigated by immuno-histochemistry, SDS-PAGE and ELISA. L-FABP immuno-histochemistry showed increased reactivity in the liver of RS patient and normal reactivity in MLS liver. L-FABP increase in RS liver was confirmed by densitometry of SDS-PAGE and ELISA method. By these two methods the increase amounted to 180% and 199% (p less than 0.02), respectively, as compared to controls. A possible role of L-FABP in the pathogenesis of RS is discussed.

Hypothermia: an unusual manifestation of Reye's syndrome

A four year old girl manifested with seizures, raised intracranial tension and altered consciousness. Laboratory investigations suggested Reye's syndrome. Later she developed fatal hypothermia. Rarity of such a case is highlighted. Probable pathogenesis of hypothermia in Reye's syndrome is discussed.

Microvesicular fatty liver in rats with resembling Reye's syndrome induced by 4-pentenoic acid

To produce an animal model of Reye's syndrome (RS), 20 adult male Wistar rats were given 10 repeated i.p. injections of 50 mg/kg 4-pentenoic acid (PA) each separated by an 8-h interval. Then, 90 min after the tenth dose, they were given a final i.p. injection of 150 mg/kg PA. Thirteen control animals were injected with vehicle only using the same time schedule. More than half the animals in each group were fed a common diet, but the others were fasted during the terminal 10-h stage. All rats were sacrificed 30 min after the last injection. At the terminal stage, in comparison with the vehicle-injected controls, hypolipemia, hypoglycemia and high titers of serum ammonia and urea N were estimated significantly in the PA-treated rats fed throughout the whole period. Hypolipemia and hypoglycemia were more prominent in the terminally fasted group than the group fed continuously. Only in the PA-treated rats fed throughout the whole period moderate morphological signs of microvesicular fatty liver were exhibited. Ultracytochemical findings and biochemical determinations showed that the major lipids in the microvesicular fatty livers were triglycerides. Morphometric analysis revealed distinct hepatic mitochondrial swelling in the PA-treated rats. Therefore, the above treatment with PA was able to induce microvesicular fatty liver in rats with resembling RS, which were fed throughout the treatment procedure, but not in the terminally fasted rats.