Aspirin and Reye's disease: a reinterpretation

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.

Plasma salicylate analysis: a comparison of colorimetric, HPLC and enzymatic techniques

Three colorimetric techniques and one enzymatic technique have been compared with an HPLC method for the analysis of salicylate in the plasma of patients after self-poisoning with aspirin. The enzymatic technique was specific but expensive to perform. The colorimetric techniques were simple, cheap and precise. The Keller method, however, was susceptible to interference from endogenous substances. We report a modification of the Keller method that eliminates most of this interference and improves the accuracy of the analysis. The new method is easier and safer to perform under emergency conditions than the Trinder technique.

Salicylate measurement: clinical usefulness and methodology

The salicylates are the most commonly used analgesic, antipyretic, and anti-inflammatory drugs. They are available in hundreds of preparations, many of which are over-the-counter medications. The easy access to large quantities of the drug and the widespread perception that the drug is harmless have contributed to salicylate intoxication becoming a serious and common problem, particularly among the pediatric and geriatric populations. Salicylate is still the major drug for the treatment of rheumatic diseases. The use of salicylate in high doses for the management of these patients requires close monitoring of serum salicylate levels because of the large interindividual variation in dose-serum level relationships and the narrowness of the therapeutic range. Thus, both for the management of patients intoxicated with salicylate and patients who are on high-dose salicylate therapy, the measurement of serum salicylate levels is an important clinical laboratory service. Recent research on the inhibitory effect of aspirin on platelet aggregation has led to the prophylactic use of aspirin in low doses as an antithrombotic drug. This new therapeutic use of aspirin can be aided by monitoring low serum levels of salicylate and perhaps aspirin itself. This article reviews the current state of the knowledge of the pharmacokinetics and clinical toxicology of salicylate, the clinical usefulness of salicylate measurement by the clinical laboratory, and recent development in the analytical technology for salicylate analysis.

Salicylate toxicity

Understanding of the pharmacologic principles and the pathogenesis of salicylate toxicity provides a basis for the optimization of clinical management. The role of salicylate as a scientifically proven cause of Reye's syndrome remains controversial despite epidemiologic data. The management guidelines discussed illustrate treatment details based on the pathophysiology of salicylate toxicity.

Confirmation of serum salicylate levels in Reye's syndrome: a comparison between the Natelson colorimetric method and high performance liquid chromatography

Serum was obtained from 11 patients with Reye's syndrome at admission and analyzed for the presence of salicylates by the Natelson colorimetric technique and high performance liquid chromatography. Salicylate levels obtained by the Natelson method had a mean of 6.00 mg/dl +/- 4.58; the mean HPLC salicylic acid level was 5.09 mg/dl +/- 5.14. The correlation coefficient was 0.985 with a linear regression line y = 0.8788x + 1.527. No other salicylate metabolites nor interfering substances were identified. Once the accuracy of the Natelson method was confirmed, the charts of 82 patients were reviewed for admission salicylate levels. The overall mean was 8.63 mg/dl (survivors, 8.45 mg/dl +/- 8.56; fatalities, 9.28 mg/dl +/- 5.34). There was no correlation found between admission salicylate level and peak ammonia level, another important index of disease severity.