Diagnosis of hepatitis of different types: methods, tests, reliability

Diagnosis of hepatitis: Hepatitis is a series of inflammatory diseases of the liver, which are often mistakenly called jaundice by the people – one of the symptoms of the disease. Most often, viruses are the culprits of the disease, but other causes can also lead to the development of hepatitis. How does the disease manifest itself, what tests should be taken to diagnose hepatitis, and how accurate are modern diagnostic methods? Let’s talk about it in the article.

Whatever causes hepatitis, its target is always liver cells: they cease to perform their functions and die. If the disease is detected at the initial stage, serious complications can be avoided. Before talking about the principles of diagnosing hepatitis, we will tell you what the most dangerous of its varieties are.

Viral hepatitis

The most common group of hepatitis. With this diagnosis, destruction in the liver cells occurs due to the penetration of specific viruses into the body. There are several forms of viral hepatitis: A, B, C, D, E and G.

A, B, D and E appear relatively the same: diarrhea, nausea and vomiting, increasing weakness, pain in the stomach and right hypochondrium, yellowing of the skin and whites of the eyes, an increase in liver size. Hepatitis C and G are more insidious – they may not manifest themselves in any way: often for many years the only symptom is enduring fatigue.

Let us dwell in more detail on the common types of viral hepatitis.

Viral hepatitis A

According to the latest data from the World Health Organization, about 1.4 million cases of this disease are registered annually in the world. The actual number of patients is much higher, since for one case of severe infection there are at least 5–10 cases of asymptomatic infection. In addition, in places where the virus is most widespread, residents rarely visit doctors.

Infection with the hepatitis A virus occurs through the use of contaminated food and water, as well as through close physical contact with the patient. This type of hepatitis is also called the disease of dirty hands, because it often infects children in sandboxes. The incubation period lasts 2-4 weeks. Symptoms of the disease are dominated by malaise, fever, loss of appetite, nausea, diarrhea, and jaundice. Almost all patients are completely cured and have lifelong immunity.

Viral hepatitis B

According to WHO statistics, in 2019 there were about 300 million patients with chronic hepatitis in the world. Hepatitis B is a life-threatening infectious liver disease that claims about 800,000 lives per year. Infection occurs through contact with blood and sexual contact. As a rule, hepatitis B develops in young children, and often the disease becomes chronic in them.

From the moment of infection with hepatitis B until the onset of the first symptoms, it can take from one to six months, on average – 80 days. The outcome of the disease can be either a complete cure or a complication in the form of a chronic disease, cirrhosis of the liver and oncology.

Viral hepatitis C

One of the most dangerous varieties of the disease. According to WHO data for 2022, about 58 million people in the world are sick with chronic hepatitis C. Approximately one third of those infected in the first six months after infection achieve a spontaneous cure, the remaining 55–85% develop a chronic disease. According to the latest data, we can talk about 2 million people. The virus is transmitted mainly through the blood – through intravenous drug use, through traumatic cosmetic and medical procedures, less often through sexual contact.

The incubation period of the disease varies from two weeks to six months – the disease is often detected when the liver and other organs and tissues are already damaged. Left untreated, hepatitis C can lead to cirrhosis and liver cancer.

Non-infectious hepatitis and their diagnosis

In addition to viruses, hepatitis can be caused by other factors, ranging from medication to alcohol. Let’s consider some of them.

Toxic and drug hepatitis

Sometimes exposure to toxins of plant and artificial origin can lead to liver damage – toxic hepatitis. The liver is an organ for detoxification: it is responsible for the neutralization of substances formed in the body and toxins coming from outside. Various toxic substances, poisons, which are contained in plants and fungi, can cause the death of liver cells.

The task of laboratory diagnosis of toxic hepatitis is aimed at its differentiation from other liver lesions. For this, the blood content of bilirubin and its fractions, AST, ALT, alkaline phosphatase, GGTP, albumin and prothrombin is examined.

In the same way, a patient with suspected drug-induced hepatitis is examined, which can be caused by taking a variety of drugs, primarily antibiotics, anticonvulsants, antitumor and non-steroidal anti-inflammatory drugs, oral
contraceptives.

Alcoholic hepatitis

In people who abuse alcohol, there is a destruction of the main cells of the liver – hepatocytes. In fact, hepatitis is the second stage of alcoholic liver disease. First, potentially reversible asymptomatic steatosis occurs, then alcoholic hepatitis, and the final stage of the disease in 20–40% of cases is cirrhosis of the liver. In cases of severe alcoholic hepatitis, the risk of mortality is high – up to 50%.

For the diagnosis of hepatitis, a liver biopsy is most informative, although there is a practice of using non-invasive diagnostics. Thus, alcoholic hepatitis is characterized by an increase in ALT, AST, bilirubin levels, GGTP, and sometimes alkaline phosphatase. At the same time, there is a decrease in albumin and prothrombin. The inflammatory process in the liver is accompanied by an increase in ESR up to 40–50 mm/h, leukocytosis, and anemia. However, not a single indicator is a reliable marker of alcoholic hepatitis.

autoimmune hepatitis

This is a rare form of hepatitis. Scientists still cannot explain why it occurs. With this type of hepatitis, immunity fails and begins to attack liver cells, as if they were foreign organisms. This form of hepatitis often accompanies other autoimmune diseases, but can also develop independently.

The main indicator of the disease is autoantibodies. ASMA, ANA, AAA, anti-LKM-1, anti-LC-1, anti-SLA, anti-SLA/LP have diagnostic value. The preferred method for their determination is RNIF, an indirect immunofluorescence reaction.

In this way, the presence of antinuclear antibodies – ANA, antibodies to smooth muscles, or SMA, and antibodies to liver and kidney microsomes – anti-LKM1 are determined. The method is also suitable for the detection of rare anti-LC1 and anti-LKM3 antibodies, if anti-LKM1 is absent. In the case of a positive result of the research, a liver biopsy is performed, which allows to get an idea of ​​the activity of the inflammatory process.

Also, if autoimmune hepatitis is suspected, it is worth checking the indicators of bilirubin, alkaline phosphatase, AST – an increase in their level is characteristic of the disease.

Methods for laboratory diagnosis of viral hepatitis

Let us dwell on the methods of laboratory diagnosis of the most common – viral – hepatitis. The universal biological material for their detection is venous blood. It is examined by ELISA and PCR methods. At the same time, instrumental examination methods, including CT, MRI, ultrasound, are ineffective for diagnosing hepatitis. They can provide information about the state and structure of the liver, but not about which specific virus hit the body and how long ago it happened. As a rule, the therapist prescribes a number of laboratory tests.

Hepatitis A

According to the clinical picture, hepatitis A does not differ from other types. Accurate diagnosis is confirmed by the following studies:

Clinical blood test with leukocyte formula and ESR. In the uncomplicated course of the disease, a decrease in the number of leukocytes and platelets, an increase in ESR, in advanced cases, the number of leukocytes, on the contrary, increases, ESR decreases.

Biochemical blood tests: study of the level of total bilirubin, free and bound bilirubin, determination of ALT, AST, gamma-glutamyl transferase GGTP, alkaline phosphatase.

Analysis for the presence of IgM antibodies to the hepatitis A virus by ELISA. These antibodies can be detected at the very beginning of the disease, when the first symptoms appear.

Determination of hepatitis A virus RNA in the blood by PCR.

Hepatitis B

For the diagnosis of hepatitis B, the same clinical and biochemical blood tests with a coagulogram are recommended as in the determination of hepatitis A, with the addition of the following studies:

in the biochemical blood test, in addition to the above, the determination of the level of cholesterol and protein fractions by electrophoresis should be included;

analysis for the presence of IgM antibodies to the hepatitis B virus by ELISA. It is considered the most reliable specific marker of the disease;

analysis for the determination of antigens and antibodies to hepatitis B. The earliest marker of this virus is HBsAg antibodies. However, it is necessary to take into account the stage of the disease – after 4-6 months, these antibodies disappear. During the incubation period of the disease, simultaneously with HBsAg in the blood serum, the HBe antigen, a marker of active reproduction of the virus, circulates.

Hepatitis C

Diagnosis of infection with the hepatitis C virus is carried out in two stages:

Determination of total IgG and IgM antibodies to hepatitis C virus in the blood.
In the case of a positive result, to confirm a chronic infection, testing is prescribed for the presence of hepatitis C virus RNA in the patient’s blood. This analysis is performed by PCR.
As an additional study to determine the degree of liver damage, a biopsy may be prescribed.