Diagnosis | Hepatitis B

Diagnosis

In the patient interview (anamnesis), the path-breaking symptoms and causes can be identified or other causes can be excluded. For example, specific questions about previous vaccinations against hepatitis B, previous transfusions or i. v. drug addiction can provide clues. During the physical examination, an acute hepatitis often reveals a painful pressure in the right upper abdomen and a palpable enlargement of the liver.

The acute infection with the hepatitis B virus is detected by the detection of immunoglobulin M in the blood, which is directed against the antigen of the core (“core”) (IgM anti-HBc). This immunoglobulin is 100% detectable in hepatitis B infection at the onset of the disease. IgM is an immunoglobulin that is produced as the earliest antibody in the course of an immune response.

It serves to activate the complement system that is part of the immune defense. In the later course of the disease, IgM is replaced by immunoglobulin G (IgG), which is produced by the B lymphocytes or plasma cells and remains in the body for a lifetime. IgG is either a sign of expired hepatitis B or a chronic course of the hepatitis.

Hepatitis B serology is the term used to describe laboratory tests that are used to assess whether a (acute or chronic) hepatitis B infection exists and what the vaccination status is. There are several different hepatitis B virus components that can be detected in the blood.Components directly associated with the virus include the HBs antigen (hepatitis B-S antigen) and the HBe antigen (hepatitis B-E antigen). In addition, serology is used to detect antibodies to components of the virus circulating in the blood.

These include anti-HBs, anti-HBe and anti-HBc. Depending on which of these antigens or antibodies are positive or negative, this allows different conclusions to be drawn about hepatitis B infection. For example, if HBs antigen is detected in the blood, this is evidence of a hepatitis B infection.

This is an acute infection because virus components are still circulating in the blood. If anti-HBc and anti-HBs are positive, but all other values are negative, this indicates that the infection has taken place but is no longer active, i.e. clinically cured. One of the values, the anti-HBs value, is used to test the vaccination status.

If the anti-HBs value is positive and all other values are negative, this proves that a vaccination against hepatitis B has taken place. When this vaccination has taken place cannot be determined from these values. While the hepatitis B serology tests the blood qualitatively for different hepatitis B markers, the titer determination involves a quantitative measurement of the anti-HBs vaccination marker.

If this value is above 100 IU/l, this indicates that the vaccination protection is (still) sufficient, a refreshment of the vaccination is not necessary. If the value is below 100, no sufficient vaccination protection is guaranteed. The titer determination is important because there are no consistent results for the hepatitis B vaccination as to whether and when a booster vaccination is necessary after the basic immunization.

Therefore, the level of the anti-HBs value is used to decide whether or not a booster vaccination is necessary. The hepatitis virus is surrounded by an envelope. Surface proteins are embedded in this envelope.

Derived from the English word for surface, they are called HBs antigen. HBs is therefore a component of the hepatitis B virus. If HBs is detected in the blood, this is an indication of an acute infection with hepatitis B.

There are several hepatitis B antigens. These are different components of the hepatitis B virus against which the human body develops antibodies when infected with the virus. The HBs antigen is a surface protein that occurs in the virus envelope.

The HBc antigen is a protein that is found in the virus nucleus. The c stands for the word core. During the replication of the virus in the human body another antigen is released, the HBe antigen.

E stands for excretory. The Hepatitis B antigens are virus components that can be detected in the blood and are markers for an infection. In an ultrasound examination, the abdomen (acute abdomen) and its organs are visualized with the help of ultrasound waves.

The transducer emits ultrasound waves that are absorbed or reflected by the various tissues it encounters. The transducer receives the reflected waves, which are converted into electrical impulses and displayed on a screen in different shades of grey. In symptomatic acute hepatitis B, the liver may be enlarged and appear slightly less echoic (i.e. darker) due to an accumulation of fluid in the liver (edema).

Chronic hepatitis B usually manifests itself with atypical changes that resemble a fatty liver-like condition. This means that the liver appears enlarged, it is more echoic (i.e. lighter) and appears smoother and rounded edges. If the chronic hepatitis persists for a longer period of time, the signs of cirrhosis of the liver are also more evident.

Depending on the stage of the cirrhosis, changes of varying severity can be observed. The caliber of the liver vessels decreases in the process of the disease. As the disease progresses, the liver shrinks and can sometimes be only 10 cm in size in the late stage.

It then also appears very bright, apparently consisting only of nodules and the edge of the liver appears uneven and bumpy. Sonography is not used to find a diagnosis because it cannot distinguish between different causes of hepatitis, but helps to estimate the extent of the disease. Liver puncture allows liver tissue to be obtained, which can then be examined finely (histologically) by the pathologist using a microscope.

There are different ways of obtaining liver tissue.The simplest type is liver blind puncture, in which, as the name suggests, the liver is “blindly” punctured with a hollow needle. In this way a tissue cylinder is obtained. This method is relatively easy to perform with a little practice and without any major aids, and is particularly suitable for diagnosing diffuse liver diseases, e.g. hepatitis or cirrhosis of the liver, which affect the entire liver.

The targeted puncture of the liver is supported by an imaging technique such as sonography or computed tomography. The needle is inserted into the liver under visual control, so to speak, so that a specific section of the liver can be punctured. Targeted puncture is always indicated in the case of diseases that affect a defined part of the liver, for example in the case of unclear spatial requirements (e.g. tumors, metastases, etc.). In such localized findings, a punch biopsy is often used because it allows more tissue to be obtained. Both puncture types are performed under local anesthesia.