How do They Test for Reye’s Syndrome?

In the probable cases of Reye syndrome, it is necessary to inquire about previous viral disease, which may precede from 1 to 6 days, and clinical symptoms of vomiting and progressive neurological involvement until reaching a coma. There may be a sympathomimetic state increased with sweating, sometimes fever, tachycardia, tachypnea and pupillary dilation. Increased hyperventilation is another fundamental clinical fact. Seizures do not usually appear until the coma is deep. It may take from 8 hours to 4 days from the first symptoms to the establishment of the coma.

How do They Test for Reye’s Syndrome?

Paraclinical Tests

There does not exist a test to detect Reye syndrome. As an alternative, the analysis for the detection of the syndrome usually begins with blood tests and with an examination to detect disorders of fatty acid oxidation and other metabolic disorders.

Sometimes more invasive diagnostic tests are needed to check other probable causes. For example:

Lumbar Puncture: Useful for ruling out similar diseases, such as an infection in the membranes lining the brain and spinal cord (meningitis) or an inflammation or infection in the brain (encephalitis).

Liver Biopsy: A liver biopsy can help to identify or rule out other diseases that may affect the liver.

Computed Tomography (CT) or Magnetic Resonance Imaging (MRI)

It can help the doctor to identify or rule out other causes of changes in behavior or decreased attention.

In blood, there are constant manifestations of liver dysfunction, with elevation of transaminases, hyperammonemia (especially in the first hours), and hypoprothrombinemia; other serum enzymes (creatine phosphokinase, lactic dehydrogenase, amylase, lipase) are also usually elevated.

The finding of hypoglycemia is common, in relation to the depletion of hepatic glycogen deposits, bilirubin rarely rises above 2-3 m%, phosphorus is usually lowered and uric acid is elevated, and it is usual that there are modifications of the amino acid pattern.

Organic acids (lactic, pyruvic, isobutyric, propionic, isovaleric and caprylic) are elevated; cholesterol, lipoproteins, coagulation factors and components of the complement system are low.

Leukocytosis is frequent (up to 40,000-50,000 / mm3) and the cerebrospinal fluid usually shows increased pressure, with low glucose (relative to plasma), normal proteins, without pleocytosis.

In the histopathological studies it is evidenced, in liver, glycogen depletion, steatosis, proliferation of peroxisomes, deformation of mitochondria, these are also altered in brain and muscle.

All these findings are an expression of the decreased activity of mitochondrial enzymes, which supports the idea that this syndrome represents the metabolic response to a mitochondrial aggression.

In the electroencephalogram, alterations in prognostic value have been described, which correlate with the clinical stages.

The diagnosis of Reye syndrome can be made by assessing the presence of

Clinical Criteria: History of previous viral infection, vomiting, encephalopathy, coma, convulsions, with other laboratory tests: elevation of transaminases and ammonia, lengthening of prothrombin time, cerebrospinal fluid normality; next to it the absence of other causes of encephalopathy or liver disease.

The differential diagnosis must be made with:

Acute Infections: Of the central nervous system. The study of cerebrospinal fluid allows the distinction because it is normal in Reye syndrome (it may show increased pressure and low levels of glucose in cerebrospinal fluid) the discovery of red blood cells or leukocytes, as well as the elevation of proteins go against this syndrome and should suggest other possibilities (meningitis, encephalitis, as well as subarachnoid hemorrhages).

Fulminant Hepatitis: It produces a picture similar to the Reye syndrome, but this is characterized by the absence of jaundice (variable in hepatitis) and liver biopsy allows, in any case, the distinction between these mentioned two entities.

Acute Pancreatitis: It can give a similar clinical picture and difficult distinction since pancreatic involvement is common in Reye syndrome.


Diagnostic doubts in a first phase will be with any acute encephalopathy of unknown origin, encephalitis, salicilic intoxication, drug overdose and acute hepatic failure.

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Pramod Kerkar, M.D., FFARCSI, DA
Pramod Kerkar, M.D., FFARCSI, DA
Written, Edited or Reviewed By: Pramod Kerkar, M.D., FFARCSI, DA Pain Assist Inc. This article does not provide medical advice. See disclaimer
Last Modified On:May 21, 2018

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