Cytomegalovirus infection (CMV) is an infectious disease of viral genesis, transmitted sexually, transplacental, household, blood transfusion. Symptomatically proceeds in the form of a persistent cold. There is weakness, malaise, headaches and joint pains, runny nose, enlargement and inflammation of the salivary glands, excessive salivation. It is often asymptomatic. Disease of pregnant women is dangerous: it can cause spontaneous miscarriage, congenital malformations, intrauterine fetal death, congenital cytomegaly. Diagnostics is carried out by laboratory methods (ELISA, PCR). Treatment includes antiviral and symptomatic therapy.
B25 Cytomegalovirus disease
Other names of cytomegalovirus infection found in medical sources are inclusive cytomegaly, viral disease of the salivary glands, disease with inclusions. CMV infection is a widespread infection, and many people, being carriers of cytomegalovirus, do not even suspect it. The presence of antibodies to cytomegalovirus is detected in 10-15% of the population in adolescence and in 50% of adults. According to some sources, the carrier of cytomegalovirus is determined in 80% of women of the childbearing period. First of all, this applies to the asymptomatic and low-symptomatic course of cytomegalovirus infection.
The causative agent of cytomegalovirus infection – cytomegalovirus – belongs to the family of human herpesviruses. Cells affected by cytomegalovirus multiply in size, so the name of the disease “cytomegalovirus infection” translates as “giant cells”. CMV infection is not a highly contagious infection. Infection usually occurs with close, prolonged contacts with carriers of cytomegalovirus. Cytomegalovirus is transmitted in the following ways:
- airborne: when sneezing, coughing, talking, kissing, etc.;
- sexually: during sexual contact through semen, vaginal and cervical mucus;
- hemotransfusion: with blood transfusion, leukocyte mass, sometimes – with organ and tissue transplantation;
- transplacental: during pregnancy from mother to fetus.
Often, cytomegalovirus has been in the body for many years and may never manifest itself and cause harm to a person. The manifestation of latent infection occurs, as a rule, with a weakening of immunity. Cytomegalovirus poses a threat in its consequences in people with reduced immunity (HIV-infected people who have undergone bone marrow transplantation or internal organs taking immunosuppressants), with a congenital form of cytomegalovirus infection, in pregnant women.
Once in the blood, cytomegalovirus causes a pronounced immune reaction, manifested in the production of protective protein antibodies – immunoglobulins M and G (IgM and IgG) and an antiviral cellular reaction – the formation of CD 4 and CD 8 lymphocytes. Inhibition of cellular immunity in HIV infection leads to the active development of cytomegalovirus and the infection caused by it.
The formation of immunoglobulins M, indicating primary infection, occurs 1-2 months after infection with cytomegalovirus. After 4-5 months, IgM is replaced by IgG, which are found in the blood throughout the rest of life. With strong immunity, cytomegalovirus does not cause clinical manifestations, the course of infection is asymptomatic, hidden, although the presence of the virus is determined in many tissues and organs. By infecting cells, cytomegalovirus causes an increase in their size, under a microscope, the affected cells look like an “owl’s eye”. Cytomegalovirus is detected in the body for life.
Even with an asymptomatic course of infection, the carrier of cytomegalovirus is potentially contagious to uninfected persons. The exception is the intrauterine pathway of cytomegalovirus transmission from a pregnant woman to the fetus, which occurs mainly during the active course of the process, and only in 5% of cases causes congenital cytomegalovirus infection, in the rest it is asymptomatic.
Congenital cytomegalovirus infection
In 95% of cases, intrauterine infection of the fetus with cytomegalovirus does not cause the development of the disease, but proceeds asymptomatically. Congenital CMV infection develops in newborns whose mothers have suffered primary cytomegalovirus infection. Congenital cytomegalovirus infection can manifest in newborns in various forms:
- petechial rash – small skin hemorrhages – occurs in 60-80% of newborns;
- prematurity and intrauterine growth restriction – occurs in 30% of newborns;
- chorioretinitis is an acute inflammatory process in the retina of the eye, often causing a decrease and complete loss of vision.
Mortality in intrauterine infection with cytomegalovirus reaches 20-30%. Of the surviving children, most have mental retardation or hearing and vision disabilities.
Acquired cytomegalovirus infection in newborns
When infected with cytomegalovirus during childbirth (when the fetus passes through the birth canal) or in the postpartum period (with household contact with an infected mother or breastfeeding), in most cases, an asymptomatic course of cytomegalovirus infection develops. However, in premature infants, cytomegalovirus can cause prolonged pneumonia, which is often accompanied by a concomitant bacterial infection. Often, when children are affected by cytomegalovirus, there is a slowdown in physical development, an increase in lymph nodes, hepatitis, rash.
Mononucleosis – like syndrome
In persons who have come out of the newborn period and have normal immunity, cytomegalovirus can cause the development of a mononucleosis-like syndrome. The course of mononuclease–like syndrome in the clinic does not differ from infectious mononucleosis caused by another type of herpesvirus – Ebstein-Barr virus. The course of the mononucleosis-like syndrome resembles a persistent cold infection. At the same time, it is noted:
- prolonged (up to 1 month or more) fever with high body temperature and chills;
- aching joints and muscles, headache;
- pronounced weakness, malaise, fatigue;
- sore throat;
- enlargement of lymph nodes and salivary glands;
- skin rashes resembling a rash with rubella (usually found in ampicillin treatment).
In some cases, mononucleosis–like syndrome is accompanied by the development of hepatitis – jaundice and an increase in liver enzymes in the blood. Even less often (up to 6% of cases), pneumonia is a complication of mononucleosis-like syndrome. However, in individuals with normal immune reactivity, it proceeds without clinical manifestations, being detected only during lung radiography.
The duration of the course of mononucleosis-like syndrome is from 9 to 60 days. Then a complete recovery usually occurs, although residual phenomena in the form of malaise, weakness, enlarged lymph nodes may persist for several months. In rare cases, activation of cytomegalovirus causes relapses of infection with fever, sweating, hot flashes and malaise.
Cytomegalovirus infection in people with weakened immunity
The weakening of immunity is observed in people suffering from congenital and acquired immunodeficiency syndrome (AIDS), as well as in patients who have undergone transplantation of internal organs and tissues: heart, lung, kidney, liver, bone marrow. After organ transplantation, patients are forced to constantly take immunosuppressants, leading to pronounced suppression of immune reactions, which causes cytomegalovirus activity in the body.
In patients who have undergone organ transplantation, cytomegalovirus causes damage to donor tissues and organs (hepatitis – during liver transplantation, pneumonia during lung transplantation, etc.). After bone marrow transplantation in 15-20% of patients, cytomegalovirus can lead to the development of pneumonia with high mortality (84-88%). The greatest danger is the situation when the donor material infected with cytomegalovirus is transplanted to an uninfected recipient.
Cytomegalovirus affects almost all HIV-infected people. At the beginning of the disease, malaise, joint and muscle pain, fever, night sweats are noted. In the future, these signs may be joined by cytomegalovirus lesions of the lungs (pneumonia), liver (hepatitis), brain (encephalitis), retina (retinitis), ulcerative lesions and gastrointestinal bleeding.
In men, disease can affect the testicles, prostate, in women – the cervix, the inner layer of the uterus, vagina, ovaries. Complications of cytomegalovirus infection in HIV-infected people can be internal bleeding from the affected organs, loss of vision. Multiple organ damage by cytomegalovirus can lead to their dysfunction and death of the patient.
In order to diagnose cytomegalovirus infection, a laboratory examination is performed. The diagnosis of cytomegalovirus infection is based on the isolation of cytomegalovirus in clinical material or with a fourfold increase in the titer of antibodies.
- ELISA-diagnostics. It includes the determination of specific antibodies to cytomegalovirus in the blood – immunoglobulins M and G. The presence of immunoglobulins M may indicate primary infection with cytomegalovirus or reactivation of chronic CMVI. Determination of high IdM titers in pregnant women may threaten fetal infection. An increase in IdM is detected in the blood 4-7 weeks after infection with cytomegalovirus and is observed for 16-20 weeks. An increase in immunoglobulin G develops during the period of attenuation of the activity of cytomegalovirus infection. Their presence in the blood indicates the presence of cytomegalovirus in the body, but does not reflect the activity of the infectious process.
- PCR diagnostics. To determine the DNA of cytomegalovirus in blood and mucous cells (in the materials of scrapings from the urethra and cervical canal, in sputum, saliva, etc.), the method of PCR diagnostics (polymerase chain reaction) is used. It is especially informative to conduct quantitative PCR, which gives an idea of the activity of cytomegalovirus and the infectious process caused by it.
Depending on which organ is affected by cytomegalovirus infection, the patient needs to consult a gynecologist, andrologist, gastroenterologist or other specialists. Additionally, according to the indications, ultrasound of the abdominal cavity, colposcopy, gastroscopy, MRI of the brain and other examinations are performed.
Uncomplicated forms of mononuclease-like syndrome do not require specific therapy. Usually, measures are carried out that are identical to the treatment of a common cold. To relieve the symptoms of intoxication caused by cytomegalovirus, it is recommended to drink a sufficient amount of liquid.
Treatment of cytomegalovirus infection in persons at risk is carried out with the antiviral drug ganciclovir. In cases of severe cytomegalovirus infection, ganciclovir is administered intravenously, because tablet forms of the drug have only a preventive effect against cytomegalovirus. Since ganciclovir has pronounced side effects (causes hematopoiesis depression – anemia, neutropenia, thrombocytopenia, skin reactions, gastrointestinal disorders, fever and chills, etc.), its use is limited in pregnant women, children and people suffering from renal insufficiency (only for vital indications), it is not used in patients without violations of immunity.
For the treatment of cytomegalovirus in HIV-infected people, the most effective drug is foscarnet, which also has a number of side effects. Foscarnet can cause a violation of electrolyte metabolism (a decrease in blood plasma of magnesium and potassium), ulceration of the genitals, impaired urination, nausea, kidney damage. These adverse reactions require careful use and timely dose adjustment of the drug.
Cytomegalovirus is particularly dangerous during pregnancy, as it can provoke miscarriage, stillbirth or cause severe congenital deformities in a child. Therefore, cytomegalovirus, along with herpes, toxoplasmosis and rubella, is one of those infections that women should be examined for prophylactically, even at the stage of pregnancy planning.
The issue of prevention of cytomegalovirus infection is particularly acute in people at risk. The most susceptible to infection with cytomegalovirus and the development of the disease are HIV-infected (especially AIDS patients), patients after organ transplantation and persons with immunodeficiency of a different genesis.
Non-specific methods of prevention (for example, personal hygiene) are ineffective against cytomegalovirus, since infection with it is possible even by airborne droplets. Specific prevention of cytomegalovirus infection is carried out by ganciclovir, acyclovir, foscarnet among patients at risk. Also, in order to exclude the possibility of infection with cytomegalovirus of recipients during organ and tissue transplantation, careful selection of donors and monitoring of donor material for the presence of cytomegalovirus infection is necessary.