respiratory syncytial virus infection
Introduction
Introduction to respiratory syncytial virus infection Respiratory syncytial virus infection, also known as respiratory syncytial virus infection, can cause characteristic fusion cells in cultured cells, which is a serious lower respiratory tract infection in infants, and a small number may be associated with a rash. The disease is transmitted by the respiratory tract infection. It has the characteristics of wide spread, high infection rate and long duration. It is spread and popular in all countries of the world. It is a major epidemic every year or every other year. It is a virus of severe lower respiratory tract infection in infants. One. basic knowledge The proportion of illness: 0.0035% Susceptible people: good for infants and young children Mode of infection: respiratory secretions Complications: atelectasis, respiratory failure, meningitis
Cause
Respiratory syncytial virus infection etiology
(1) Causes of the disease
It is caused by respiratory syncytial virus or fusion virus (RSV). It is a paramyxovirus RNA type with a diameter of 100-140 nm. The nucleocapsid is composed of 32 symmetric 20-faced capsids. It has a capsule and is not destroyed by ether or chloroform. Human cells, diploid cells and primary monkey kidney cells can be used to culture viruses, and special fusion cells can be produced. The fluorescent antibody technology can be used to detect the virus in the infected cell cytoplasm. The respiratory tract infection has the characteristics of wide spread, high infection rate and long duration. It is spread and popular in all countries of the world, and it has a large epidemic almost every year or every other year. It is one of the viruses of severe lower respiratory tract infection in infants.
(two) pathogenesis
Respiratory syncytial virus infection is caused by airborne droplets or directly into the respiratory tract of susceptible persons. RSV invades the body and first proliferates in the nasopharyngeal mucosa, causing upper respiratory tract infection, immune function is low, infants, the elderly, RSV can be nasopharynx Prolongs to various levels of bronchi and alveoli, which develops into severe bronchitis, bronchiolitis and pneumonia. After the respiratory virus invades the ciliated epithelial cells on the surface of human respiratory tract, it replicates and spreads in it and directly causes damage to the infected cells, resulting in damage. Local lesions or symptoms of systemic toxic blood.
The tissue damage caused by some viruses may be mediated by the body's immune response. For example, respiratory syncytial virus has the least direct damage to respiratory ciliated epithelial cells, but it can cause serious respiratory diseases in infants and young children. The most common age is the mother-in-law. The stage with the highest antibody level; after vaccination, the condition of the naturally infected person is aggravated, etc., suggesting that the pathogenesis may be related to the immune response. The pathological changes of respiratory virus infection include nasal, pharyngeal, laryngeal mucosal congestion, edema, exudation and mononuclear. Infiltration of cells, some cells may undergo degeneration, necrosis, shedding, and inclusion bodies in the cytoplasm or nucleus of epithelial cells. The degree of lesions is related to the type, type and location of the virus. In a few days, the epithelial cells can regenerate and return to normal. If the lesion involves the bronchioles, epithelial cell necrosis, exfoliation, extensive mononuclear cell infiltration in the bronchioles, fibrin, cell debris and sticky mucus can block the lumen and cause atelectasis, emphysema, viral pneumonia The initial manifestation is progressive reduction of cilia, formation of vacuolar cells in epithelial cells, degeneration of epithelial cells, substantial necrosis of alveoli, and wilting Alveolar wall can also be seen necrosis and thickening, interstitial edema and monocytes, lymphocyte infiltration, and bacterial infection, mucosal congestion, neutrophil infiltration and mucopurulent secretions can be seen, severe lung abscess can occur , sepsis and suppurative changes in multiple organs.
Prevention
Respiratory syncytial virus infection prevention
Respiratory tract discharge should be strictly disinfected, breast milk feeding can increase antibodies, breastfeeding should be encouraged, live attenuated vaccine, 95% of children can produce neutralizing antibodies, antibodies can also be detected in nasal secretions, and newly developed temperature sensitive in recent years. (ts) Fission vaccination can be used to protect children and adults with antibodies, but not for children with negative serum antibodies.
Complication
Respiratory syncytial virus infection complications Complications, atelectasis, respiratory failure, meningitis
In severe cases, airway obstruction, atelectasis, hypoxia, cyanosis, respiratory failure and even suffocation may occur. Some patients may develop meningitis and myelitis.
Symptom
Symptoms of respiratory syncytial virus infection Common symptoms Shortness of breath, respiratory tract obstruction, respiratory failure, conduction block, inhalation, insomnation, ataxia, atresia, maculopapular alopecia, atelectasis
It mainly occurs in infants and young children from 6 months to 4 years old, mostly in winter and spring. The incubation period is 4 to 5 days. The infants mainly present with fever, bronchitis and bronchial pneumonia, with cough, vomiting, shortness of breath, and a few with pleural effusion. Liquid, X-ray examination can be seen in the lung inflammatory infiltration, severe cases can occur airway obstruction, atelectasis, hypoxia, cyanosis, respiratory failure and even suffocation death, and some children may develop meningitis, myelitis, ataxia, Hemiplegia, myocarditis, complete conduction block, etc. Some sick children can suddenly die without aura symptoms. Larger children and adults show common upper respiratory tract infection symptoms. Individual children can have diffuse erythema and plaque on the face and trunk. The papules spread to the forearms, buttocks, and there may be a small amount of ecchymosis. The rash subsides for 1 day and the body temperature drops.
In the winter season, such as infants with bronchiolitis and pneumonia should first consider the disease, detect RSV antigen, conditional for virus isolation and serum complement binding test and neutralizing antibody detection.
Examine
Respiratory syncytial virus infection check
White blood cell count is generally (5 ~ 15) × 109 / L, most <10 × 109 / L, neutrophils more than <70%, nasopharyngeal secretions can be cultured to isolate virus, adult complement binding assay and neutralizing antibody An increase in titer can confirm the diagnosis.
X-ray examination showed inflammatory infiltration of the lungs.
Diagnosis
Diagnosis and identification of respiratory syncytial virus infection
It needs to be differentiated from upper respiratory tract infection, airway obstruction, and bacterial lung infection.
