Useful articles / August 8, 2019
People are accustomed to blaming unhealthy food and stress for the occurrence of gastritis and ulcers, although in fact most problems with the gastrointestinal tract are due to the insidious bacterium Helicobacter pylori.
Helicobacter pylori is a spiral-shaped parasitic bacterium that can penetrate the mucous membrane of the stomach and duodenum. It produces toxins that affect the mucous membrane of these organs and cause pathological changes. The peculiarity of Helicobacter pylori is that the aggressive acidic gastric environment is a very comfortable habitat for it. And, if most bacteria die in such an aggressive environment, then Helicobacter adapts well to it. According to statistics, more than 80% of the Russian population is infected with this bacteria.
To accurately diagnose and prescribe treatment for gastrointestinal problems, the patient must be tested for the presence of the bacterium Helicobacter pylori in the body . What laboratory diagnostic methods exist today and how accurate are they?
Detailed description of the study
Helicobacter pylori is a bacterium that affects the gastric mucosa due to its resistance to acidic environments.
It is assumed that infection with this infection occurs at an early age and is transmitted to children from parents or in preschool institutions. The most likely route of infection is considered to be the fecal-oral route of infection when living with an infected person in the same house, as well as during a long stay in a large group.
In addition, the oral route of transmission of infection through saliva and kissing has been recorded. There have been suggestions about the possibility of Helicobacter pylori infection during fibrogastroscopy - an examination through an endoscope that has been insufficiently treated with disinfectants.
After penetration into the stomach, Helicobacter pylori colonizes its mucous membrane, causing gastritis of the antrum of the stomach. The bacterium is protected from exposure to an aggressive acidic environment by producing alkali (ammonia) and some other substances that damage the gastric mucosa.
In response to Helicobacter pylori entering the body, the immune system produces antibodies. Initially, antibodies of class A and M are formed, they are soon replaced by immunoglobulins of class G. In most cases, the body is not able to completely defeat this infection, which predetermines the preservation of a high level of class G antibodies to it.
When combined with other unfavorable conditions, such as stress, poor diet, and infection with this bacterium, it leads to the formation of erosions and stomach ulcers. The following symptoms are noted:
1. pain in the upper abdomen (on an empty stomach);
2. nausea;
3. belching air;
Some people are asymptomatic when infected with Helicobacter pylori. Long-term damage to the gastric mucosa by this bacterium leads to the development of atrophy and decreased acid production. The risk of developing stomach cancer and lymphoma increases. A particularly high risk of developing cancer is observed in those whose relatives suffered from it.
Determining the presence of Helicobacter pylori infection in the body is important for early diagnosis of gastric pathology. Class G antibodies are produced several weeks after infection and are detected throughout life in the presence of bacteria in the body.
This test is relevant, in combination with other antibodies (IgA, IgM), as a primary diagnosis of this infection, but is not recommended for assessing the effectiveness of treatment, because IgG may persist for a long time even after successful therapeutic measures.
How is the Helicobacter test interpreted?
If the research is qualitative, then there can be only two results - “positive” or “negative”. If a quantitative method is used, the analysis standards will depend on the specific laboratory, and only a doctor can interpret them.
How can you become infected with Helicobacter pylori?
The bacterium Helicobacter pylori is called an intrafamilial infection and it occurs in 80% of the Russian population. The main modes of transmission: fecal-oral, oral-oral, household. This could be kissing, sharing utensils, eating insufficiently clean vegetables and fruits, failure to comply with personal hygiene rules... Most often, infection occurs in childhood through household contact. If, for example, parents have the bacterium Helicobacter pylori in their bodies, then it is passed on to their children. Another question is in what period of a person’s life it will manifest itself. Do not forget that most diseases of the upper digestive tract occur precisely because of this bacterium. Gastroenterologists warn that 100% of people with Helicobacter develop gastritis over time. Therefore, it is important to detect it and undergo treatment on time.
References
- Ivashkin V.T., Maev I.V., Abdulganieva D.I., Alekseenko S.A., Ivashkina N.Yu., Korochanskaya N.V., Mammaev S.N., Poluektova E.A., Trukhmanov A. S., Uspensky Yu.P., Tsukanov V.V., Shifrin O.S., Zolnikova O.Yu., Ivashkin K.V., Lapina T.L., Maslennikov R.V., Ulyanin A.I. . Practical recommendations of the Scientific Community for Promoting the Clinical Study of the Human Microbiome (NSOM) and the Russian Gastroenterological Association (RGA) on the use of probiotics for the treatment and prevention of gastroenterological diseases in adults. Russian Journal of Gastroenterology, Hepatology, Coloproctology. 2020
- GuevaraB, CogdillAG. Helicobacter pylori: A Review of Current Diagnosticand ManagementStrategies. DigDisSci. 2020
- Choi IJ, Kim CG, Lee JY. Family History of Gastric Cancer and Helicobacter pylori Treatment. N Engl J Med. 2020
FGDS with Helicobacter pylori
The endoscopic examination method is considered the most accurate test. A biopsy of the gastrointestinal tract reveals not only the presence or absence of bacteria, but also determines the stage of the disease, and also allows you to immediately find out whether the organs are affected or not.
This study is carried out using a gastroscope (a long tube inserted into the gastrointestinal tract through the mouth and equipped with a camera and a device for taking a tissue sample). In addition to taking biomaterial for biopsy, the gastroenterologist visually examines the condition of the walls of the duodenum and stomach.
Two hours before the biopsy, you should not smoke or drink, and your last meal should be 12 hours before.
FGDS with Helicobacter pylori can be performed under anesthesia. The procedure lasts about twenty minutes. The doctor will determine the ulcer, if any, during the examination, and the patient will receive the test results the next day.
Our clinic has the opportunity to conduct FGDS with Helicobacter pylori and other studies.
How can Helicobacter be detected by blood?
The body of any person reacts to an infectious pathogen by developing a protective reaction. The level of antibodies in the blood increases. They are formed by specific protein complexes and cells. The diagnostic level allows you to identify:
- the presence of antibodies and quantify them;
- the structure of proteins (immunoglobulins) that are involved in the antigen-antibody reaction;
- DNA of cells involved in inflammation.
Accordingly, the methods used are called:
- enzyme immunoassay (ELISA);
- analysis for antibodies and their protein components (immunoglobulins);
- polymerase chain reaction (PCR) method.
PCR is one of the necessary diagnostic methods
Method for studying specific immunoglobulins
Immunoglobulins (Ig) are special proteins that take an active part in the fight against the infecting antigen.
Immunoglobulins are located on the surface of immune cells and reach the microorganism anywhere in the body
But they are not produced immediately. In the diagnosis of Helicobacter infection, importance is attached to three types of immunoglobulins, designated: A, M, G. Each plays a role in the inflammatory process:
- IgG - is considered a marker that confirms the presence of bacteria in the body; it can be detected already in the third or fourth week after the introduction of the pathogen; it is important that high IgG titer numbers remain in a person for several months after recovery and death of Helicobacter;
- IgM is an indicator of early infection, it is rarely detected, the patient does not yet have any symptoms of the inflammatory process, so detection can establish infection in the family;
- IgA - indicates an early stage of infection or a pronounced inflammatory process; it can be detected in the saliva and gastric juice of an infected person, which indicates the high activity and infectiousness of the pathogen.
The positive side of the method can be considered:
- high efficiency of laboratory testing, IgG is detected in 95-100% of patients, IgA - in 67-82% of cases, IgM - 18-20%;
- Using a blood test, by comparing immunoglobulin titers with previous indicators, you can monitor deviations from the norm, the development of the pathological process, and the effectiveness of treatment;
- the test is more likely than antibodies in the blood to prove infection.
Flaws:
- a month must pass before the main marker (IgG) appears, this plays into the hands of a delay in diagnosis;
- after treatment, especially in elderly patients, the titer remains high for a long time (IgG is detected in half of the patients for a year and a half);
- there is no way to recognize the acute form of the disease from the passive entry of bacteria into the stomach.
To compensate for the shortcomings of the method, a total count of immunoglobulins is used.
general characteristics
The pathogenic microorganism H. pylori, causing gastritis, duodenitis, gastric ulcer (in 70% of cases) and duodenal ulcer (in 90%). Recent data indicate a close connection between Helycobacter pillory and the development of cancer. Determination of the level of immunoglobulins is the most reliable (specificity 91%, sensitivity 97%), the most accessible, least invasive method for diagnosing Helicobacter pylori infection. These antibodies appear 1-2 weeks after infection and are indicators of an acute process. Used to diagnose the acute period of Helicobacter pylori infection. Women are characterized by higher serum IgA levels. An increase in the proportion of IgA in the IgA/IgG ratio is a prognostic sign in the development of gastric cancer.
Features of infection in children
Morbidity statistics show that 35% of preschool children and 75% of schoolchildren are infected with helicobacteriosis in Russia. Small children get the infection from mothers licking nipples, spoons when feeding, from saliva during kissing, and sharing utensils.
Detection of antibodies in the blood allows a timely course of therapy to cure the child. But at the same time, you should look for bacteria carriers among adult family members. Since it has been established that 3 years after the course of treatment, 35% of children experience re-infection. After a period of 7 years, the number of infected reaches 90%.
The most common clinical picture of the lesion develops in a child:
- from nausea;
- refusal to eat;
- dyspepsia (excessive regurgitation, bloating);
- unclear pain.
Preparing for analysis
To obtain objective indicators, you need to carefully prepare for testing for Helicobacter pylori.
Necessary preparations:
- Complete smoking cessation the day before the test. Nicotine negatively affects the gastric mucosa, distorting test results.
- Complete abstinence from alcohol. The reason is the same.
- Prohibition on drinking tea and coffee, which negatively affect the gastrointestinal tract.
- Temporary restriction on food intake for 8 hours before analysis.
Since blood for Helicobacter testing is taken from a vein on an empty stomach, you can take some food and water with you to the clinic.
Diagnostic capabilities of the PCR method
Using polymerase chain reaction, bacterial DNA, the basis of the microorganism's gene composition, can be detected in the patient's blood. Therefore, this method is considered the most reliable. The result is assessed as positive (the bacterium is in the body) or negative (the patient does not have the bacterium). While confirming the presence of Helicobacter, the method does not provide information about its pathogenicity. It is known that the pathogen does not cause illness in many people.
In addition, when taking the test, you need to take into account that no treatment should be carried out (not just antibiotics). This is hardly achievable, since all patients take some kind of medication to relieve discomfort or pain. The analysis is carried out in specialized centers, so its availability is low.
Decoding the analysis results
Despite the fact that the decoding of the indicators should be entrusted to the doctor who referred for the examination, all patients want to find out their results on their own.
How much is the norm for Helicobacter pylori? The norm of bacteria content when testing venous blood: 0-0.9 units/ml .
Interpretation of other meanings:
- 0.9-1.1 units/ml – the likelihood of Helicobacter pylori infection is doubtful;
- More than 1.1 units/ml – bacteria are definitely present in the body. High risk of developing stomach ulcers and stomach cancer.
The norm for the urease test is the absence of crimson color in the color of the material. The norm for bacterioscopic examination is the absence of pathogens.
Indications for testing
It is difficult to imagine that a person who does not have symptoms of the disease would go for a full-scale examination unnecessarily.
Symptoms predisposing to testing for Helicobacter pylori:
- Gastralgia (pain in the stomach and intestines) of varying intensity. Appear during or after meals, caused by enzyme deficiency and impaired digestion of food and its stagnation in the stomach.
- "Hunger pains." They appear 2-3 hours after eating and disappear during meals. Due to damage to the mucous membrane, its sensitivity worsens, the patient feels how food and water pass through the digestive tract.
- Intense heartburn. It occurs due to the backflow of aggressive gastric juice into the esophagus that is not intended for this, and with frequent repetitions it is a symptom of pathology.
- A feeling of heaviness that occurs even after taking minimal portions of food. The patient has a feeling of a full stomach.
- Frequent nausea not caused by objective reasons (for example, toxicosis of pregnancy).
- A combination of stomach pain with vomiting and inability to eat and drink.
- Slight discomfort in the projection of the stomach, loss of appetite, mild heaviness. Often appear at the initial stage of heliobacteriosis.
- The presence of mucus in the stool.
Any of these symptoms is a reason to immediately consult a doctor for examination and treatment.
How does the procedure work?
The study allows you to determine the level of antibodies in the blood against bacteria, including Helicobacter pylori. The basis of the method is donating blood for analysis. Basically, serum is required, which is collected from a vein.
The biomaterial is collected in a container with a coagulant gel. With its help, plasma is released that is used in further research.
The only complication during the procedure is the occurrence of bruises when a vein is punctured. To make the hematoma resolve faster, it is enough to apply a dry, warm object.
The immunoglobulin G test result can be obtained 24 hours after blood collection. To study the IgA type indicator, an additional 8 hours will be required.
The price for the procedure ranges from 340 rubles for one specific antibody to 900 rubles for all three types.
Contraindications for carrying out
ELISA analysis should be abandoned in the following cases:
- during pregnancy;
- with possible convulsions;
- with damage to the skin or subcutaneous fat;
- with phlebitis of the vein.
