Reviewed By: Pramod Kerkar, MD, FFARCSI

Can a Virus Cause your Liver Enzymes to be Elevated?

Liver damage, which can be caused by a virus, is invariably associated with serum elevation of aminotransferases. Both AST and ALT are very concentrated in the liver; AST is also found in heart, skeletal muscle, kidneys, brain, and red blood cells while ALT is found in low concentration in skeletal, muscle and kidneys. Therefore, the elevation of ALT is more specific for liver damage.

The elevation of liver enzymes can cause liver damage or alteration of the bile flow. It can occur in a patient with symptoms or symptoms compatible with liver disease or it can occur in isolation, as an unexpected finding, during a routine laboratory study.

The liver is a complex organ, the central metabolism of carbohydrates, fats and proteins. In addition, it synthesizes and secretes bile, lipoproteins and plasma proteins, including coagulation factors. They maintain blood glucose levels through the uptake and storage of glucose as glycogen (glycogenesis), by its degradation to glucose when necessary (glycogenolysis) and through the formation of glucose from other sources, such as amino acids (gluconeogenesis). With the exception of most lipids, products that are absorbed from food pass directly from the intestine to the liver through the portal system. Microscopically, the primary functional unit of the liver is the acinus, territory supplied by each terminal branch of the hepatic artery and the portal vein. The liver is divided into 3 zones according to the blood supply; zone 3 is the one with the lowest perfusion and the one with the highest number of mitochondria (organelle whose function is the production of energy). Liver diseases often result in elevated enzymes, with levels exceeding two standard deviations from normal values, whereas their decrease, with the exception of albumin, has no clinical significance.

Viral Hepatitis

Acute viral hepatitis are part of a pathological entity that lasts less than 6 months and can present asymptomatically with minimal alterations of laboratory tests, until rapid evolution of the acute lesion towards extensive necrosis, associated with fatal prognosis. When thinking about viral hepatitis, there is a tendency to evaluate mostly hepatitis viruses; however, other infectious agents must be considered to make a good differential diagnosis.

Viral hepatitis is produced mainly by viruses phylogenetically different from each other, which are known as hepatitis A, B, C, D, E, F and G viruses. In all these cases, hepatocytes are the main host cells and target infection, although they are also capable of infecting other cells. Viral hepatitis also includes acute syndromes of liver disease due to other human viruses that are not specifically hepatotropic, among which, in particular, the human cytomegalovirus (CMV) and the Epstein-Barr virus (EBV) stand out; acute hepatitis associated with herpes simplex virus (HSV), varicella-zoster virus (VZV), rubella virus (RV), human B19 parvovirus and adenovirus infections have also been reported.

Enzyme tests include the alanine transaminase (ALT), an unilocular enzyme because it has a higher percentage of localization in the cytoplasm and is found more frequently in liver tissue and aspartate aminotransferase (AST) located at the cytoplasmic and mitochondrial levels, so it denominates bilocular. It is widely distributed in skeletal muscle, kidney, brain, liver, and heart. Any alteration in these tissues will be reflected in an increase of these enzymes, which will be directly proportional to the tissue damage.

The elevation of the alkaline phosphatase (ALP) may be indicative of cholestatic disease fundamentally, as well as hepatic infiltrative processes. As for gamma-glutamyltraspeptidase (GGT), it identifies the liver as the organ responsible for the elevation of alkaline phosphatase; both elevated enzymes are indicative of damage to the liver cell. Total bilirubin and its direct form are considered an actual value of hepatic glucuronidation function, because they reflect the ability of the liver to collect, process and secrete bilirubin into bile, whose increased serum causes jaundice. The liver is the main site in which the synthesis of most of the plasma proteins is carried out, mainly albumin, alpha and beta globulins, and the coagulation factors that therefore provide useful information to assess the synthesis and liver production.

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Pramod Kerkar

Written, Edited or Reviewed By:

, MD,FFARCSI

Pain Assist Inc.

Last Modified On: June 7, 2018

This article does not provide medical advice. See disclaimer

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