Relevance and epidemiology
Viral hepatitis causes colossal economic damage: per single case, it leads all infectious pathologies in the Russian Federation, and in total damage, it is second only to acute respiratory infections and influenza. There are hundreds of millions of infected people worldwide, which requires general practitioners to have confident diagnostic and therapeutic skills.
True (primary) acute viral hepatitis is classified as independent nosological entities. They are caused by specific viruses (A, B, C, D, E). Viral hepatitis A is characterized by an enteral transmission mechanism. It is precisely the taxonomy and biological properties of the pathogen that determine the routes of infection. When taking an epidemiological history, it is extremely important to consider the patient's living conditions: for example, living in a dormitory is a strict epidemiological indication for isolating and hospitalizing the patient.
Pathogenesis and clinical presentation
Studying acute viral hepatitis of various etiologies in a single block is advisable due to the universality of their basic characteristics: shared pathogenesis links, similar clinical and laboratory syndromes, and general principles of therapy. The mechanism of infection development follows a complex path from the entry portal to the stage of viremia and direct hepatocyte damage.
Acute viral hepatitis has a typical (cyclical) course, which is strictly divided into four periods:
- Incubation
- Preicteric
- Icteric
- Convalescence (recovery) period
The clinical presentation is based on several key syndromes: cytolysis (destruction of liver cells), cholestasis (impaired bile flow), mesenchymal inflammation, and general intoxication. In severe cases, life-threatening outcomes such as acute liver failure (ALF) and acute hepatic encephalopathy (AHE) may develop.
Laboratory diagnostic algorithm
To assess the nature of jaundice, the depth of hepatocyte damage, and the severity of the disease, a comprehensive examination plan is prescribed:
- Blood biochemistry test: evaluates total protein, bilirubin (total and its fractions to determine the type of hyperbilirubinemia), cytolysis markers (ALT, AST), cholestasis markers (ALP, GGT), and a coagulogram (specifically, the prothrombin index — PTI).
- General clinical tests: standard complete blood count (CBC) and urinalysis (UA).
- Etiological verification: serological blood testing to detect specific markers of viral hepatitis.
Differential diagnosis and treatment
Differential search is primarily conducted based on the leading syndrome — jaundice. The physician must clearly rule out suprahepatic (hemolytic) and subhepatic (obstructive) jaundice, as well as parenchymal lesions of other etiologies.
It should be remembered that the clinical presentation of acute liver damage can be not only an independent disease, but also secondary hepatitis — a specific manifestation or severe complication of other systemic infections (e.g., caused by herpesviruses, enteroviruses, or adenoviruses). Furthermore, in modern practice, the pathomorphosis of infections is observed: the number of combined lesions (mixed hepatitis) such as co-infection or superinfection is increasing.
The basis of therapy for viral hepatitis A is pathogenetic treatment. Adequate detoxification therapy and timely relief of emerging symptoms come to the forefront.
For quick memorization of the periods of the typical cyclical course of hepatitis, use the acronym IPRC: Incubation, Preicteric, Icteric, Reconvalescence (Recovery).
Class and exam questions
Which blood biochemistry indicators indicate cytolysis syndrome?
To assess the cytolysis syndrome and the depth of hepatocyte damage, ALT and AST enzyme levels are determined in the biochemical blood test.
With which types of jaundice does viral hepatitis A need to be differentiated?
Differential diagnosis is performed with suprahepatic (hemolytic), subhepatic (obstructive), and parenchymal (hepatic) jaundice of other etiologies.
What is the basis of treatment for hepatitis A?
The basic approach includes pathogenetic treatment, where detoxification therapy plays the leading role, along with symptom relief.
Does acute liver damage always indicate primary viral hepatitis?
No, secondary hepatitis syndrome exists. It acts not as an independent nosology, but as a manifestation of other systemic viral infections (for example, in herpesvirus or adenovirus infection).
What else to study on this topic
- Mechanisms of development of acute liver failure (ALF) and encephalopathy.
- Development of post-infection immunity and prevention measures for hepatitis A.
- Pathogenesis of mesenchymal inflammation syndrome in viral liver damage.
- Clinical and laboratory criteria for assessing the severity of acute viral hepatitis.
- Risk of chronicity, development of cirrhosis, and hepatocellular carcinoma in hepatitis with a parenteral transmission mechanism.
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