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Every year, the frequency of infection of pregnant women with viral infections is increasing. This affects the increase in the number of miscarriages, miscarriages, stillbirths, intrauterine growth retardation and malformations of various organs, generalized viral infections of newborns.
A separate place among these viral diseases is occupied by cytomegalovirus infection (CMVI). Obstetrician-gynecologists often do not pay due attention to this virus, considering it relatively safe in obstetric terms. The probable reason for such an attitude of doctors to CMVI is its frequent latent course. It often does not manifest itself in any way in adults, although it causes irreparable harm to a child developing in utero.
The latent course of CMVI creates difficulties for its timely diagnosis. Insufficient attention to the problem of cytomegalovirus has led to the fact that, according to medical statistics, up to 2,5% of children are currently born infected with cytomegalovirus. Families planning the birth of a child should study the problem of CMVI in detail and be properly examined before such a responsible step.
What is CMVI
Cytomegalovirus is a virus from the herpesvirus family, which also includes herpes simplex and herpes zoster viruses. Cytomegalovirus got its name due to the fact that the cells affected by it increase significantly in size and acquire a specific appearance – the “owl’s eye”.
The virus is characterized by low virulence and slow replication (DNA reproduction), which explains its frequent latent course. On environmental objects, the pathogen persists for a long time. Dies at temperatures above +56°C or below -20°C.
Infection with the cytomegalovirus occurs sexually (through sperm, cervical mucus, vaginal secretion), hematogenous (through infected blood), vertical (through the blood-brain barrier, during childbirth), lactogenic (through breast milk), contact (through saliva) way.
Children can become infected during natural childbirth when passing through the birth canal of a sick mother, through breast milk. Children transmit the infection to each other in preschool institutions, for example, through bites. In the scientific literature, there is information about the transmission of infection by the fecal-oral and contact-household route.
Clinical manifestations
The presence of CMVI in the body does not mean that a person is sick. The causative agent of cytomegaly can circulate in the blood of a person all his life, but never manifest himself. In this case, a person with the virus can infect those in contact with him, for example, a sexual partner or a child.
In some cases, cytomegalovirus causes a disease similar to a common cold, without any special consequences for its carrier.
The main manifestations of CMVI are:
- subfebrile fever (up to 38 ° C);
- catarrh of the nasopharynx;
- coryza;
- enlargement of the salivary glands;
- whitish plaque on the oral mucosa;
- an increase in submandibular lymph nodes;
- headache;
- weakness;
- general malaise;
- fast fatiguability.
CMVI poses a great danger to people with reduced immunity. In such patients, the virus can proceed as a generalized infection and even serve as a provoking factor for the development of oncological pathologies.
However, active primary cytomegalovirus is most dangerous for pregnant women, since it can lead to the development of congenital CMVI.
In the first trimester of pregnancy, cytomegalovirus can lead to:
- intrauterine fetal death (miscarriage, missed pregnancy);
- congenital malformations (absence or underdevelopment of the brain, hydrocephalus, deafness, intrauterine growth retardation, heart and vascular defects);
- delayed psychomotor development of the child;
- increased convulsive activity or muscle weakness, paralysis.
With intrauterine infection of the fetus at later stages of pregnancy (in the second or third trimester), the newborn may develop an acute generalized cytomegalovirus infection with multiple organ damage (liver, spleen, brain).
Diagnostic methods
Laboratory diagnosis of CMVI is based on the detection of virus DNA in biological material (blood, urine) and discharge from various organs (saliva, vaginal secretion, cervical mucus, urethral scraping, semen). The virus is detected by cytological (the “owl’s eye” phenomenon), virological (infection of a culture of fibroblasts or thyroid cells with a biomaterial), molecular genetic (using polymerase chain reaction) methods.
To identify the activity of the process and the level of viral load in the blood serum, the total concentration of antiviral antibodies and their individual fractions (immunoglobulins of classes M and G) is determined. This study is carried out using various serological methods (enzymatic immunoassay, neutralization reactions, complement fixation or indirect hemagglutination).
Indications for examination
Only a large-scale examination for CMVI can detect and cure cytomegalovirus in a timely manner.
Testing is recommended for women who:
- planning a pregnancy;
- have a burdened obstetric history (miscarriage, miscarriage, stillbirth, birth of children with intrauterine infection or malformations);
- are pregnant and, according to the results of ultrasound, an intrauterine infection was detected in the fetus;
- pregnant and immunocompromised.
Together with these women, children born by them earlier and sexual partners of women are also subject to a comprehensive examination for CMVI.
Interpretation of results
In itself, the detection of a virus in human biological material does not mean a disease. In people with a normal immune system, the CMVI pathogen may not cause clinical manifestations, but such a person is a potential source of infection. At the same time, the absence of the cytomegalovirus in the biomaterial also does not always mean that the person is healthy.
The causative agent may not be detected for several reasons:
- laboratory diagnostic error;
- violation of the method of sampling, storage of biomaterial or analysis;
- low sensitivity of laboratory test systems;
- low viremia (viral load);
- low immune response (immunodeficiency).
A false-negative result can only be detected with the help of a comprehensive examination: a simultaneous analysis for the genes of the virus and antibodies to it.
In the first weeks after infection, the so-called “acute antibodies” are actively produced in the human body – class M immunoglobulins (IgM). They provide the body’s primary defense and serve as an immune shield until the body begins to produce mature antibodies to infection – immunoglobulins G (IgG). The presence of IgG in the blood indicates the age of the infection. The presence of immunoglobulins of two classes at the same time – M and G – indicates an active infectious process in the body.
The results of laboratory tests for CMVI are interpreted depending on the combination of the sought-after indicators found.
| The presence of the pathogen CMVI | Class M immunoglobulins | Immunoglobulin class G | Interpretation of the result |
|---|---|---|---|
| No | No | No | Seronegative, no CMV infection |
| Discovered | No | No | Possible “serological window” (antibodies have not yet developed) |
| Discovered | No | No | False-positive result possible, repeat after 2 weeks |
| Discovered | Discovered | No | Possible initial stage of CMVI, repeat antibody test after 2 weeks |
| Irrelevant | None or found in titer less than 1:200 | Discovered | High chance of chronic CMVI |
| Irrelevant | Found in titer over 1:200 | Discovered | High probability of recent primary CMVI infection, recurrence in 2 weeks |
Thus, only a comprehensive assessment of the presence or absence of viral DNA in the patient’s biomaterial, as well as immunoglobulins of different classes and their titer (concentration) in the blood, makes it possible to establish the diagnosis of CMVI, its form (acute, chronic) and stage (replication, latent).
For screening diagnostics of pregnant women, it is recommended to carry out the determination of IgM and low-avid IgG. Low-grade antibodies are detected in the blood during the first 3-5 months after infection, therefore they are a sign of a “fresh” infection. In case of questionable results, a re-examination of the patient after 2 weeks is recommended.
To clarify the form and stage of the disease, other highly sensitive studies can also be used (determination of antibodies to individual proteins of the virus, antibody titer A and IgG avidity, and others).
Treatment and prevention
Drug treatment of a viral infection involves the appointment of antiviral drugs (Isoprinosine, Groprinosin, Normomed), which act directly on the DNA of the virus. The course of treatment with these drugs is at least 20 days, with breaks of up to 10 days, and at least three courses in a row. Antiviral agents, even if they do not relieve the patient of CMVI, however, they suppress the activity of the pathogen and transfer the disease from the replication stage to the latent one.
CMVI in patients with a normal level of immunity is not subject to treatment. The same applies to pregnant women, but for a different reason – the medications used can do more harm to the developing child than good. Therefore, it is recommended to be examined for this infection and, accordingly, to treat it before pregnancy.
There is no specific prevention of CMVI. Live and killed vaccines have not been shown to be effective against the pathogen. Preventive measures are reduced to observing the rules of personal hygiene and maintaining immunity (vitamin-mineral complexes).
Limiting contact with children under 5 years of age (if possible) also helps pregnant women avoid infection.
Screening for the presence of antibodies to CMVI is carried out in antenatal clinics without fail for all pregnant women when they are registered. However, this method of examination only states the fact of infection of the pregnant woman, but does not reduce the likelihood of intrauterine infection of the fetus. The most competent way to avoid congenital cytomegalovirus infection is only the examination of a married couple for CMVI at the stage of pregnancy planning, when it is possible to influence the activity of the pathogen with medication, and not expectantly.