Clinical features and prognosis of Reye's syndrome

Twenty three sporadic cases of Reye's syndrome diagnosed according to widely accepted criteria were seen between 1979 and 1982. The patients were younger than those reported from North America (median age 9 months), girls were twice as common as boys, and the syndrome presented twice as frequently in the summer 6 months. The annual incidence was 1.4 cases/100 000 among children aged less than 4 years. The prodrome consisted of upper respiratory symptoms in 61% of the children and even less specific features in more than 25%; two patients had varicella. Six of the 23 patients presented after a prodrome of less than 24 hours with 'acute collapse', simulating 'near miss' cot death associated with profound hypoglycaemia, and in four of these there was an unfavourable outcome. Intensive care methods including judicious fluid restriction coupled with 'prophylactic' hyperventilation (87%), direct monitoring of intracranial pressure (70%), and barbiturate coma (52%) achieved neurologically intact survival in 74% of patients. Failure to recognise the syndrome early enough or to manage it appropriately resulted in four deaths. To help reduce overall mortality in the United Kingdom paediatricians have a duty to acquaint family doctors and emergency department staff of the earliest clinical features of Reye's syndrome and of the need for immediate hospital referral.

Abnormal regulation of pyridoxal 5'-phosphate in Reye's syndrome

Seeking to determine the effect of liver disease associated with Reye's syndrome on the regulation of plasma pyridoxal 5'-phosphate, we measured this compound in plasma from 11 patients with biopsy-proven Reye's syndrome. Its concentrations in plasma are significantly higher [37.5 (SD 6.13) micrograms/L] at the onset of the disease than after treatment [8.50 (SD 2.9) micrograms/L] or in a group of hospitalized patients with no evidence of liver disease [8.4 (SD 1.5) micrograms/L]. The concentration of pyridoxal 5'-phosphate in plasma at the time the patients entered the hospital correlated significantly with their activities of serum alanine aminotransferase.

Free fatty acids in an animal model of Reye's syndrome

Recent studies have indicated that viral infections, aspirin treatment and hyperammonemia are associated with Reye's syndrome. It has also been reported that free fatty acids in serum and total lipids in the liver of Reye's syndrome patients are elevated during illness. The role of the lipid changes in the development of the disorder cannot be optimally studied in human patients, because infection and aspirin ingestion occur prior to the earliest symptoms of Reye's syndrome. Effects of influenza B infection, aspirin treatment and hyperammonemia on the level of free fatty acids, total lipids and triacylglycerols in serum and liver of an animal model of Reye's syndrome are reported here. Hyperammonemia was produced in young, male ferrets either by feeding them small amounts of an arginine-deficient diet after overnight fasting or by an intraperitoneal injection of jackbean urease. The ferret model resembled Reye's syndrome in developing increased levels of individual and total serum free fatty acids, liver triacylglycerol and total lipids. The results also indicate that influenza infection or aspirin treatment, or both, while increasing the severity of encephalopathy in the deficient ferrets, did not cause a significant change in the level of serum free fatty acids. Other results suggest that elevation of serum ammonia, serum free fatty acid or liver lipids, either singly or in various combinations, does not provide conditions that can explain the rapidly developing encephalopathy in the arginine-deficient ferrets.

Identification of long chain dicarboxylic acids in the serum of two patients with Reye's syndrome

Sera from two patients with Reye's Syndrome were analysed by computerized capillary gas chromatography--mass spectrometry profiling techniques. The most striking abnormalities were the accumulation of long chain dicarboxylic acids. Four saturated dicarboxylic acids (dodecanedioic, tetradecanedioic, hexadecanedioic, and octadecanedioic), and six unsaturated long chain dicarboxylic acids (dodecenedioic, tetradecenedioic, tetradecadienedioic, hexadecenedioic, octadecadienedioic, and octadecenedioic) were identified. The C16 and C13 dicarboxylic acids have never been reported for Reye's Syndrome or any other dicarboxylic acidemias. The data might reflect marked increase of extramitochondrial omega-oxidation of long chain fatty acids or impaired metabolism of omega-dicarboxylic acids formed in Reye's patients.

Measurement of true salicylate concentrations in serum from patients with Reye's syndrome

Patients with Reye's syndrome who have been given aspirin are said to maintain higher-than-anticipated salicylate concentrations in blood, for longer than expected. We explored whether this could be attributed to spurious results from nonsalicylate compounds in the Trinder reaction for salicylates. All of 63 organic acids and amines examined that form colored complexes with Trinder's reagent had detectable absorbance at 540 nm at 0.2 g/L, including some endogenous compounds known to be increased in Reye's syndrome patients and many others endogenous in humans. By subjecting deproteinized sera to thin-layer chromatography and eluting the salicylate fraction before complexing it with ferric ion, true salicylate can be measured quantitatively and differentiated from interfering compounds. In addition, when we examined the effect of salicylate on palmitate binding to serum proteins, we found that salicylate concentrations of 0.2 g/L displaced [16-14C]palmitate binding to protein more in Reye's syndrome patients than in Reye's syndrome survivors or children with influenza. This suggests the presence of atypical binding characteristics for salicylate and palmitate in the acute disorder but not in survivors or children with influenza.

Ornithine carbamoyltransferase deficiency in an adult male patient: significance of hepatic ultrastructure in clinical diagnosis

Ornithine carbamoyltransferase (OCT) activity was deficient (8% of control) in the liver of a 21-year-old man who died after suddenly becoming comatose. Activities of other enzymes of the urea cycle in the liver were normal. There was no known prior illness or injury; the patient, however, had been taking liquid protein supplements to his diet. Hyperammonemia and orotic aciduria were present, and the concentration of lysine in the plasma was elevated. Survey of earlier reports indicates that neither the specific deficiency of hepatic OCT nor the urine and plasma findings provide a basis for definitive diagnosis of the patient's illness as primary OCT deficiency or as Reye's syndrome. Indeed, the age of the patient at onset of symptoms and the absence of any prodromal infection argue against the OCT deficiency being either primary or a sequel to Reye's syndrome. We suggest that it was secondary to mitochondrial injury caused by an unknown agent. Electron microscopic study of hepatocyte ultrastructure lends support to this view; abnormalities of the patient's mitochondria (bizarre, elongated shapes) do not resemble those seen in Reye's syndrome, nor have abnormalities been found in primary OCT deficiency.

Abnormal polyunsaturated fatty acid patterns of serum lipids in Reye's syndrome

Fatty acid patterns of the serum lipids were measured in 17 children with Reye's syndrome (RS). Serial measurements of total serum free fatty acids (FFA) showed that levels were increased during RS and, after recovery, were significantly lower in the patients who survived. Fatty acid patterns of serum FFA, triglycerides, and phospholipids in patients with RS were significantly different from those in controls. In RS the polyunsaturated fatty acid content of phospholipids was less than control values; in the FFA, it was higher. This was consistent with the possible involvement of increased phospholipase activity. The increase in polyunsaturated fatty acids in FFA, the precursors of prostaglandins, suggests that a grossly disturbed prostaglandin pattern may occur in RS. These changes in lipid metabolism may be related to the abnormal hepatic and neurological functions observed in RS.

Serum salicylate concentrations in Reye's disease. A study of 130 biopsy-proven cases

Serum salicylate concentration was measured at admission in 130 children with liver-biopsy-confirmed Reye's disease. Mean serum salicylate was 12.3 mg/dl and mean salicylate concentrations by neurological grade (Lovejoy) were: stage I, 12, stage II, 13, stage III, 11, stage IV, 13, and stage V, 13 mg/dl. However, mean serum salicylate (15 mg/dl) at admission in 21 patients who died or had serious neurological deficits was significantly higher than that in 103 patients who survived without neurological sequelae (10 mg/dl). Serum salicylate in a group of 27 age-matched, community-matched control children collected consecutively over the period 1978-80 was less than 2 mg/dl, and children with varicella or influenza had salicylate concentrations indistinguishable from apparently well classmates or siblings. It is impossible to determine from this data whether salicylates are involved in the aetiology of or in determining the outcome of Reye's disease. Increased concentrations of salicylates at admission could be the result of excessive dosage because of a greater severity of the prodromal illness, or to diminished excretion because of impaired hepatic metabolism. It seems likely that serum salicylate concentrations entered the toxic range in many patients with Reye's disease before they presented for treatment. Most had been vomiting and had diminished oral intake for 33-55 h before hospital admission. Since the average number of hours from the beginning of vomiting to admission was no different in non-comatose and comatose cases, the time at which salicylate concentration was measured in relation to the last dose was probably similar in the two groups and therefore does not account for the higher levels in children with poor outcome. Salicylates are mitochondrial toxins and mitochondria are known to be significantly injured in Reye's disease; therefore, it seems wise to avoid the use of aspirin in children during outbreaks of Reye's disease.

Encephalopathy of Reye's syndrome: a review of pathogenetic hypotheses

The pathogenesis of Reye's syndrome encephalopathy was analyzed in terms of uniform criteria designed to clarify and assist evaluation of the leading hypotheses. Three of these hypotheses derive from known metabolic sequelae of hepatic mitochondrial dysfunction and the severe systemic catabolism of protein, fats, and carbohydrates that characterize the syndrome biochemically: hyperammonemia, hyperfattyacidemia, and hyperlactatemia. In addition, there is a fourth hypothesis of generalized mitochondrial insult affecting brain, muscle, and other organs as well as liver. The weight of evidence favors hyperammononemia as a sufficient factor while recognizing important interrelationships with the other observed biochemical derangements. How the catabolism and hepatic mitochondrial dysfunction are produced by the triggering viral infection remains unknown. Therapeutic efforts have thus far not succeeded in definitive metabolic intervention. Such reversal of the clinical syndrome would lead to confirmation of the necessary pathogenetic factors; this type of intervention remains the chief goal of metabolic research in Reye's syndrome.

Serum enzyme alterations in arginine-deficient, influenza-infected ferrets: a potential animal model of Reye's syndrome

Young male ferrets developed hyperammonemia and encephalopathy soon after eating a diet lacking arginine. Because of this characteristic and their known susceptibility to influenza infections, they were further tested as an animal model for Reye's syndrome (RS), a childhood disorder which sometimes develops following influenza and which is characterized in part by encephalopathy, hyperammonemia, and elevated serum transaminase levels. Either the deficiency or infection alone resulted in minor elevations of serum ornithine carbamyl transferase (S-OCT) activities and together resulted in substantial elevations. These and associated alterations are discussed in relationship to the metabolic disorders occurring in RS.

Red blood cell insulin binding studies in Reye's syndrome survivors and families

RBC insulin binding was examined in Reye's survivors and families of affected patients to determine whether their previously reported hyperinsulinemic responses to oral glucose are accompanied by alterations in insulin binding and could contribute to the hypercatabolism seen in this disorder. The mean (125I)-insulin binding to 3 X 10(9) RBC's was 5.7 +/- SEM 0.4 percent in survivors compared to 6.6 +/- 0.3 in siblings (p less than .05) and 6.6 +/- 0.4 in control children (p = .05). Sex and maturity differences were found with higher binding values in men than women as well as higher values in men than boys. Receptor numbers in survivors were comparable to control values. Average affinities varied widely. Plasma insulin levels were low in the fathers (9 +/- SEM 1.4 uU/ml compared to 18.3 +/- 1.8 for control men and 20 +/- 4.5 for mothers of affected patients). The acute syndrome is accompanied by hypercatabolism in the presence of increased plasma insulin levels and familial clustering of cases and recurrences are known to occur. Reduction in insulin binding may play a role in the acute disease if such is shared by more traditionally hormone-responsive cells.

Serum ornithine carbamyl transferase activities in Reye's syndrome

Serum levels of ornithine carbamyl transferase (S-OCT), glutamic oxaloacetic transaminase and glutamic pyruvic transaminase were compared for 37 Reye's syndrome patients with regard to variation with clinical stage an serum ammonia levels. In stage I patients, the mean S-OCT activities were greater and the serum ammonia levels lower than found with patients in the more advanced stages. Covariation of these two parameters was found only in the more advanced stages. No significant correlation with stage or serum ammonia levels was found for S-GOT or S-GPT activities. These observations are discussed in terms of their relevance to reports of an early transient decrease of hepatic OCT activity in Reye's syndrome.

Lactic acidemia in Reye's syndrome

Plasma lactate level was measured in 21 patients with Reye's syndrome and was compared with neurologic state as rated on a simple coma scale. Significant elevations in plasma lactate, ranging from 2 to 15 mEq/liter, were noted in all patients. There was a close correspondence between stage of coma at the time the sample was drawn and lactate levels. The correlation of plasma lactate level with clinical stage could not be accounted for by differences in glucose. PO2, PCO2, pH, blood pressure, or serum osmolality. In contrast, blood ammonia level correlated with the severity of the encephalopathy early in the course only and often returned to normal in patients with persistent coma. Only measurements of hepatic dysfunction such as SGOT and SGPT levels of failed to correlate with clinical state. All patients had a metabolic acidosis; in five patients it was uncompensated. Lactate accounted for nearly all (mean 81%) of the observed base deficit. The findings suggest that lactic acidemia is an important metabolic component of Reye's syndrome.

Ultrastructural alterations of the lymphocytes from a patient with Reye's syndrome

The ultrastructural alterations of the peripheral blood mononuclear cells of a patient with Reye's syndrome are reported. The involved cells were lymphocytes which showed marked nuclear changes such as irregular or highly convoluted nuclei, multilobulated nuclei, presence of scanty chromatin, and large nucleoli. Changes of the cytoplasmic organelles involved the mitochondria and dense bodies with well defined surrounding membrane appeared. The possibility that these findings indicate a viral etiology of the disease is discussed.

Aflatoxin and Reye's syndrome: a case control study

Aflatoxin levels were determined in serum and urine of 17 patients with Reye's syndrome and in control subjects. No significant difference in aflatoxin levels was found for the two groups. However, 23% of all persons studied had levels of aflatoxin indicative of recent exposure. Aflatoxin levels were associated with ingestion of cornmeal and corn bread but not peanut-containing products. This prevalence of aflatoxin may be of public health importance.