Cytomegalovirus disease

Introduction to cytomegalovirus disease Cytomegalovirus (CMV) infection has been paid more and more attention. Because the infected cells are giant cells, inclusion bodies are visible in the cytoplasm and nucleus, it is also known as cytomegalic inclusion disease (CID). After infection, the virus can be confined to the parotid gland, and some can cause systemic infection. Most CMV infections are subclinical, and those with dominant infections have diverse clinical manifestations, and severe cases can be fatal. Because cytomegalovirus can cause stillbirth, miscarriage, and premature birth through intrauterine infection, it can also lead to congenital malformation. Therefore, the prevention and treatment of this disease affects eugenics and population quality. basic knowledge Proportion of the disease: the incidence rate of children is about 1% Susceptible people: no special people Mode of infection: non-infectious Complications: abortion, rubella, herpes simplex

Cause of cytomegalovirus disease

(1) Causes of the disease

CMV belongs to the subfamily of human herpesvirus, has obvious host species specificity, is the largest and most complicated virus in human herpesvirus family; CMV is spherical, about 300nm in diameter, composed of double-layered fat The outer membrane of the protein is coated; its genome is a 230kb linear double-stranded DNA molecule containing about 200 kinds of protein coding genes. CMV has poor resistance to the outside world, heating at 65 °C for 30min, ultraviolet irradiation for 5min, ether can kill it. Live, not acid-resistant, CMV has only one serotype, commonly used ADl69 as a representative strain for serological testing.

(two) pathogenesis

Cytomegalovirus can be widely present in the tissues of various organs of infected patients, and infection can directly cause damage to infected host cells; in addition, pathogenic effects may be produced by immunopathological mechanisms.

Cytomegalovirus mainly invades epithelial cells, and all major organs (lung, liver, brain, kidney, spleen, heart, intestine), glands (parotid gland, gonad), and nervous system can be involved, and the infected cells are degenerated. The volume increases with giant cell, then disintegrates, leading to local necrosis and inflammation. Granuloma and calcification can occur after necrosis of brain tissue. The giant cell-like changes of the infected cells have the following characteristics: the cell volume is significantly enlarged. 10 ~ 40 m; the nucleus also becomes larger, the cytoplasm is relatively less, inclusion bodies can appear in the cytoplasm and nucleus, eosinophilic inclusion bodies can be seen in the nucleus, red, surrounded by a translucent halo, It is separated from the nuclear membrane to make it look like an owl eye.

Cytomegalovirus disease prevention

Pregnant women with positive CMV antibody should strengthen perinatal medical care. If necessary, amniotic fluid should be taken for CMV antibody detection. Positive patients (especially anti-CMV IgM positive) suggest that intracranial infection of CMV has occurred. According to the survey, this type of investigation The probability of intrauterine infection of the fetus in the fetus after re-pregnancy is reduced, so it is possible to discuss with the patient whether the pregnancy considers abortion, especially the time of the intrauterine infection may be within the first 4 months of pregnancy, and This pregnancy is the first pregnancy of this woman, with a higher risk of intrauterine infection of CMV. Abortion may be beneficial to eugenics, but if the couple is not easy to conceive for some reason, this pregnancy is a precious child, then it cannot If you make a decision, you can use B-ultrasound to check the fetus to help make decisions.

Strengthening screening for cytomegalovirus disease in donors of organ transplants (including bone marrow transplants), including screening for cytomegalovirus disease for blood sources used in organ transplant surgery, can help prevent cytomegalovirus disease or latency The onset of sexual infections increases the success rate of organ transplantation.

Vaccines for the prevention of cytomegalovirus disease have been developed and are still being tested.

Cytomegalovirus complications Complications, abortion, herpes simplex

Intrauterine infection of CMV is an important cause of abortion and congenital disability. About 5% to 10% of intrauterine infected neonates that appear normal at birth will appear to varying degrees within a few years after birth. Physical or mental developmental disorders such as dullness, abnormal behavior, and motor disorders, in view of toxoplasmosis ("T"), other pathogens ("O"), rubella virus ("R") , cytomegalovirus ("C"), herpes simplex virus (here "H") can cause similar harm through intrauterine infection, so together they are collectively referred to as "TORCH syndrome", is reproduction One of the important topics currently facing health care.

In addition, studies have shown that CMV infection may have carcinogenic effects and may be one of the causes of coronary stenosis.

Symptoms of cytomegalovirus disease Common symptoms Deadborn fetus umbilical cord hepatosplenomegaly convulsions chills abortion coma HIV infection body pain

Acquired infection

Most cases of latent infection or mild symptoms, but a few patients with clinical manifestations are more serious, neonatal patients with perinatal infection (some of which may be infected in the uterus) may be prolonged pneumonia; giant cells in children and adults Viral hepatitis (symptoms and signs similar to general viral hepatitis), some patients can be expressed as chills, fever, sore throat, headache, body pain, blood lymphocytes, up to 10% to 20%, its clinical The performance is similar to the infectious mononucleosis caused by EB virus infection, but the heterophilic agglutination test is negative and can be identified. According to statistics, about 8% of patients with infectious mononucleosis are caused by CMV. Caused by infection.

For patients with immunosuppressive status, CMV infection can lead to serious clinical manifestations. Because organ transplant recipients often need immunosuppressive treatment, CMV infection is one of the major causes of serious complications after organ transplantation, such as hepatitis. , ulcerative gastrointestinal inflammation, pneumonia, etc.; some can lead to postoperative death, or forced to remove the transplanted organs, such patients with CMV infection mainly from donors (donor organs and a large number of transplants required) CMV infection may be lurking in blood transfusions, but it may also be due to the activation of the original CMV concealed infection, but the latter may be milder than the former, and human cytomegalovirus disease is also common in HIV (human immunodeficiency virus). Infected people, after HIV infection becomes an AIDS patient, it is easy to form a systemic disseminated CMV infection, which is an important cause of death for AIDS patients.

2. Intrauterine infection

It is one of the important ways for human cytomegalovirus infection to infect the fetus in the uterus through the placenta. 90% of the infected fetus is a recessive infection, and only 10% is a clinical infection, but sometimes the consequences are more Severe, especially when the infection occurs within the first 4 months of pregnancy, it is more likely to cause fetal damage. For example, some infected fetuses are stunted, underweight at birth, or have various forms of congenital malformations, such as microcephaly, limbs. Malformation, congenital heart disease, squinting, blindness, etc., or short-term jaundice, hepatosplenomegaly, pneumonia, myocarditis, bleeding tendency, lethargy, coma, convulsions and other multi-system organ damage, can die within weeks .

Intrauterine infection of CMV can also cause stillbirth, miscarriage, and premature birth. In a group of 3810 neonatal epidemiological investigations, the positive detection rate of anti-CMV-IgM in cord blood samples was 1.5%; in this group of 40 cases In the cord blood specimens of stillbirth and stillbirth, the positive detection rate of anti-CMV-IgM was as high as 32.5%.

In neonates, infants with interstitial pneumonia, or hepatitis with mononucleosis, variant lymphocytes, especially those with congenital malformations, should consider this disease, adults receive blood transfusion, organ transplantation, or immunosuppression After treatment, mononuclear cells appear, and there are variant lymphocytes, fever, rash, and hepatosplenomegaly. The disease should also be considered.

Peripheral blood anti-CMV IGM positive indicates the recent presence of CMV infection, which can be diagnosed in infants and young children. Because pregnant women's peripheral blood IgM type antibodies cannot pass through the placental barrier, CMV can be diagnosed if the neonatal cord blood anti-CMV IgM test is positive. Intrauterine infection (preservation of umbilical cord blood samples should be taken to avoid maternal blood contamination), infants and young children with only a single anti-CMV IgG test positive, should be followed up for 6 to 12 months, to observe whether the titer has a significant increase High, because the detection rate of CMV antibody in adult population is very high, the detection of CMV antibody for adult patients has limited significance in the diagnosis of this disease.

Inspection of cytomegalovirus disease

Heavier patients may have increased white blood cell counts and mutated lymphocytes in the blood; infants and young patients often have anemia, and platelet counts decrease; patients with CMV hepatitis in the liver may have abnormal liver function.

The use of PCR technology for CMV gene detection can provide direct evidence of the presence of virus in patients; its sensitivity is high, and it can be used to report in a few hours, which has become an important means for clinical diagnosis of CMV infection or poisonous state; It should be carried out in an experimental medical laboratory that has passed the technical certification, and care should be taken to avoid contamination during the operation, and the reaction conditions should be strictly controlled to eliminate the false positive reaction that may be caused by PCR technology.

The patient's urine, saliva, blood or biopsy tissue samples were collected and inoculated with human diploid fibroblasts for in vitro culture. The virus can be diagnosed by isolation of the virus; however, CMV growth is slow, and cultured cell lesions can be observed 4 to 6 weeks after inoculation. , can not be used to meet complex equipment conditions, so it is still difficult to promote the application in clinical practice.

Cell smear pathology or biopsy can be used to detect characteristic giant cell-like cells and eosinophilic inclusions in the nucleus, which is helpful for the diagnosis of this disease, but its detection rate is not high. And can not only be used as a basis for diagnosis, if the detection of CMV antigen by cell immunohistochemistry technology can improve the positive detection rate, and can be diagnosed accordingly.

Immunoelectron microscopy can be used for virus identification.

Diagnosis and diagnosis of cytomegalovirus disease

Detection of cytomegalovirus genes in patient specimens by PCR can help to diagnose the disease; early in the first 3 weeks after birth, the presence of CMV can be detected from the urine or saliva samples of newborns, which is the intrauterine CMV. Provide evidence for infection.

In recent years, it has been reported that for positive donors and recipients of kidney transplant surgery, quantitative detection of serum CMV antigen titer using a highly sensitive kit can help determine whether to perform antiviral therapy.

The patient's heterophilic agglutination test is negative, and can be differentiated from infectious cytomegaloosis caused by EB virus. The differential diagnosis should be distinguished from viral hepatitis and other causes of liver enlargement and jaundice. For patients with congenital malformations, or stillbirth, abortion, premature birth and other so-called "TORCH syndrome", it should be associated with other causes of such diseases, namely toxoplasmosis, rubella virus infection, herpes simplex virus infection, and other possible pathogens. Infection (such as treponema pallidum, etc.) one by one identification.

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