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What causes hepatitis A?
Last reviewed: 06.07.2025
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[ Pathogenesis of hepatitis A
In hepatitis A, a direct cytopathic effect of the virus on the liver parenchyma is assumed. Taking this into account, the pathogenesis of the disease can be presented as follows. The virus penetrates the stomach with saliva, food masses or water, and then into the small intestine, where it is apparently absorbed into the portal bloodstream and penetrates hepatocytes through a related receptor, where it interacts with biological macromolecules involved in detoxification processes. The consequence of such interaction is the release of free radicals, which initiate the processes of lipid peroxidation of cell membranes. Increased peroxidation processes lead to a change in the structural organization of the lipid components of the membranes due to the formation of hydroperoxide groups, which causes the appearance of "holes" in the hydrophobic barrier of biological membranes and, consequently, increases their permeability. The central link in the pathogenesis of hepatitis A occurs - cytolysis syndrome. Biologically active substances move along the concentration gradient. In the blood serum, the activity of hepatocellular enzymes with cytoplasmic, mitochondrial, lysosomal and other localization increases, which indirectly indicates a decrease in their content in intracellular structures, and, consequently, a reduced bioenergetic mode of chemical transformations. All types of metabolism (protein, fat, carbohydrate, pigment, etc.) are disrupted, resulting in a deficit of energy-rich compounds and a decrease in the bioenergetic potential of hepatocytes. The ability to synthesize albumin, blood clotting factors, various vitamins is impaired, the use of glucose, amino acids for the synthesis of protein, complex protein complexes, biologically active compounds worsens; the processes of transamination and deamination of amino acids slow down, difficulties arise in the excretion of conjugated bilirubin, cholesterol esterification and glucuronidation of many other compounds, which indicates a sharp violation of the detoxifying function of the liver.