Neonatal cytomegalovirus infection
Introduction
Introduction to neonatal cytomegalovirus infection Neonatal cytomegalovirus infection is the most common congenital viral infection in humans. It refers to the birth of a child born to a mother infected with CMV. CMV infection is confirmed within 2 weeks of birth. It is caused by intrauterine infection, and the incidence is in live births. 0.18 ~ 6.2%. The incidence of CMV infection in newborns in underdeveloped countries was 1.2% (0.9 to 1.3%), and in moderately developed countries it was 0.39% (0.3 to 0.5%). Because the typical change of infected cells is that the cells become larger, and inclusion bodies appear in the nucleus and cytoplasm, this disease is also known as cytomegalic inclusion disease (CID), which is also one of the important causes of congenital malformations. basic knowledge The proportion of illness: 0.05%-0.09% Susceptible people: infants and young children Mode of infection: vertical infection of mother and baby Complications: hydrocephalus, convulsions in children, interstitial pneumonia, thrombocytopenic purpura, epilepsy
Cause
Neonatal cytomegalovirus infection etiology
(1) Causes of the disease
The population is generally susceptible to HCMV and can be repeatedly infected.
Early infection (45%):
The virus is present in the host's pharynx, salivary glands, cervix, vaginal secretions, urine, semen, milk and blood, which can cause congenital infections, perinatal infections and early postnatal infections. Perinatal mother-to-child transmission is most common. Including transplacental infection, retrograde infection through the cervix, infection through the birth canal.
Postpartum infection (35%):
It mainly refers to postpartum level infections. Infants are infected by breastfeeding. Because the sick infants can emit viruses from the mouth, respiratory tract and urine, the horizontal transmission of the baby can occur in the middle of the baby, causing the infection of the disease in infants.
(two) pathogenesis
HCMV has the biological characteristics of latent activity, and it mainly causes two changes after invading the human body:
1. Perform virus replication: produce a typical cytomegalovirus called a toxigenic infection.
2. No progeny virus replication: does not cause cytopathic conditions called non-toxic infection or latent infection (nontoxigenic or latent infection), endogenous latent virus can be activated under certain conditions to cause recurrent infection, The cells infected with HCMV are obviously enlarged, the diameter can reach more than 20m, the nucleus also increases, often on the side of the cell, and the inclusion body is on the side of the nucleus. There is an unstained halo separating it from the nuclear membrane. The cells are changed to a typical "owl-like" state. There are often plasma cells in the vicinity of giant cells, lymphocytes infiltrate, and HCMV lurks in the placental choriocarcinal tissue after infection of HCMV in pregnant women, causing morphological changes of the placenta and enabling the growth and development of the fetus. And conditions worsen, resulting in repeated fetal infection, HCMV will also affect the secretion of chorionic gonadotropin, placental lactogen, etc., resulting in intrauterine growth retardation, stillbirth, premature birth and stillbirth, etc., early pregnancy can lead to normal embryo development Effects, fetal malformations, stillbirths, etc.
The lesions caused by HCMV infection are multi-system, multi-organ. There are data showing that the brain is a typical invaded site, which is characterized by hydrocephalus, cerebral calcification, local softening and hemorrhage, stellate cell hyperplasia, perivascular inflammation. Sexual infiltration and dural nodules, mainly involving the proximal tubules when the kidney is involved, often with interstitial cell infiltration; giant cells in the alveolar and bronchial epithelium, and mononuclear cell infiltration, in neonatal cases, can be found Extramedullary blood cell formation and round cell infiltration or giant cells can also be seen; liver pathological changes can be seen in hepatocyte edema and similar chronic hepatitis-like changes, can also cause severe hepatitis changes, inclusion bodies involving intrahepatic bile duct epithelial cells, causing cholangitis, Cholestatic and jaundice.
Prevention
Neonatal cytomegalovirus infection prevention
First, pre-pregnancy check: If you take 2 ml of blood for screening, if you suspect that there is a virus infection, you need to re-diagnose, you need to draw blood; if you find a virus infection, you need blood test after treatment to check the treatment. effect.
Second, if the pregnant woman does not have a pre-pregnancy check, but is infected with the virus after pregnancy, it needs immediate treatment, but also an intrauterine prenatal diagnosis, the chance of pregnant women infected with the virus to the fetus is about 30%, so the child should be taken Organize the test. If it is found within 60 days of pregnancy, you can use the fluff to check. If you are pregnant for about 6 months, you can take the cord blood for testing, and also monitor the fetus, such as ultrasound monitoring. Once the fetus is found to be deformed, it is recommended. Termination of pregnancy.
Complication
Neonatal cytomegalovirus infection complications Complications, hydrocephalus, convulsions, interstitial pneumonia, thrombocytopenic purpura, epilepsy
The disease is often multi-system, multiple organs involved, more complications, such as nervous system damage to microcephaly, hydrocephalus, brain calcification, convulsions and chorioretinitis; often interstitial pneumonia, thrombocytopenia Sexual purpura, sequelae common growth retardation, mental retardation, dyskinesia, epilepsy, vision loss (optical atrophy), hearing impairment (neural deafness).
Symptom
Symptoms of neonatal cytomegalovirus infection common symptoms deafness convulsions skin ecchymosis thrombocytopenia jaundice optic atrophy hepatosplenomegaly calcified hair hydrocephalus hydrocephalus
The clinical manifestations of this disease vary depending on the patient's infection pattern, age, immune status, and comorbidities.
1. Congenital infection: In addition to abortion, stillbirth in infected fetuses, about 5% of live infants show typical systemic CID, ie multiple systems, multiple organ involvement, and 5% of atypical clinical manifestations The remaining 90% are subclinical. The neonatal CID is characterized by mononuclear-macrophage system and central nervous system involvement, such as small for gestational age, microcephaly, jaundice, hepatosplenomegaly, and skin ecchymosis. , hydrocephalus, brain tissue calcification, etc. According to Boppana et al (1992) analysis of 106 cases, the main signs and symptoms of this disease are purpura (76%), jaundice (67%), hepatosplenomegaly (60%), Microcephaly (53%), underweight (50%), premature delivery (34%) and chorioretinitis, hydrocephalus, brain calcification and low calcium convulsions, etc., severe cases are many days or weeks after birth Within the death; survivors 90% have sequelae, such as growth retardation, mental retardation, dyskinesia, epilepsy, vision loss (optical atrophy), hearing impairment (neural deafness).
2. Perinatal infection: Mainly through the birth canal infection during delivery or retrograde infection through the cervix and postpartum lactation infection, there are no symptoms of infection at birth, 2 to 4 months after the onset, mostly subclinical, with respiratory tract and Main symptoms of the digestive system, such as stimulating cough (pertussis-like), shortness of breath, cyanosis, interstitial pneumonia, jaundice, hepatosplenomegaly, thrombocytopenic purpura, the mortality rate of this disease can reach 30%, Pneumonia combined with respiratory failure is the main direct cause of death. Some studies have found that HCMV primary infection in the first trimester, damage to the fetal nervous system is more serious than secondary infection and secondary infection in the second trimester and third trimester.
Examine
Examination of neonatal cytomegalovirus infection
You can diagnose with any of the following items.
1. Isolation of HCMV: Isolation of HCMV from tissues such as urine, blood, saliva, and milk.
2. Detection of cytomegalovirus: Except for other viral infections, a typical cytomegalovirus is seen in the cells of the test tissue.
3. Serum specific antibody detection
(1) Serum anti-CMV IgG: Conversion from negative to positive indicates primary infection.
(2) Serum anti-CMV IgM: Positive results indicate HCMV infection; if the antibody CMV-IgG is negative at the same time, indicating primary infection; but the ability of newborns to produce IgM is poor, so even if infected with HCMV, false negatives can occur.
4. Specific monoclonal antibody detection: CMV antigen is detected from a test tissue or cell by a specific monoclonal antibody to indicate HCMV activity, and CMV antigen is also detected from peripheral blood cells, which is also called CMV antigenemia.
5. Molecular hybridization or polymerase chain reaction method: A CMV-DNA specific fragment is detected from a test material by molecular hybridization or polymerase chain reaction, indicating that the CMV infection may be a latent infection or an active infection.
6. X-ray examination: The lungs showed interstitial pneumonia.
7. B-ultrasound: There are changes such as hepatosplenomegaly.
8. EEG: Abnormal waveform.
Diagnosis
Diagnosis and diagnosis of neonatal cytomegalovirus infection
Diagnostic criteria
The diagnostic criteria for this disease (Trial, October 1994, Wuhan) includes both clinical and laboratory evidence:
1. Clinical diagnosis basis: It can be confirmed that HCMV invasion in the host body is called CMV infection regardless of whether there is any symptom or lesion.
(1) Classified according to the way the infection is obtained:
1 congenital infection (congenital infection): children born to mothers infected with HCMV, confirmed within 14 days of birth (including 14 days) HCMV infection, caused by intrauterine infection.
2 Perinatal infection: Children born to mothers infected with HCMV have no HCMV infection within 14 days of birth, and HCMV infection is confirmed within 3 to 12 weeks after birth, which is the baby's birth or sucking. Breast milk infection.
3 postnatal infection or acquired infection: infection from postpartum levels, mainly through breastfeeding infections and horizontally transmitted infections caused by infants.
The first two ways in newborns are the most important.
(2) Classification according to clinical signs:
1 Symptomatic infection: symptoms and signs associated with HCMV infection, when damage to two or more organs or systems of the host, called systemic infection, more common in congenital infections; mainly concentrated in the host An organ or system, such as the liver or lungs, is called CMV hepatitis or CMV pneumonia.
2 subclinical infection: no clinical symptoms and signs, in non-primary types in newborns.
Differential diagnosis
It should be differentiated from other diseases in TORCH syndrome (rubella, herpes simplex and toxoplasmosis), in addition to syphilis, Listeria or other bacterial and infectious encephalopathy, such as sepsis, infectious mononucleosis Identification, lymph node tuberculosis, etc., mainly rely on pathogens and immunological examination to confirm the diagnosis.
1. Congenital Toxoplasma infection: CMV performance and prognosis are similar to congenital toxoplasma infection, mainly relying on laboratory tests for differential diagnosis.
2. Infant hepatitis: Liver pathological changes can be seen in hepatocyte edema and similar chronic hepatitis-like changes, which can cause severe hepatitis changes, inclusion bodies involving intrahepatic bile duct epithelial cells, causing cholangitis, cholestasis and jaundice, the main point of identification is CMV clinical manifestations For multi-system, multiple organ damage and laboratory confirmation of HCMV invasion in the host, a diagnosis of CMV infection can be made.
3. Others: Pathological jaundice and other infectious encephalopathy with other causes, identification of meningoencephalitis, mainly relying on laboratory test results.
