Other viral pneumonia

Introduction to other viral pneumonia In addition to common viral pneumonia, human viral pneumonia can be caused by other viruses such as respiratory syncytial virus, parainfluenza virus, adenovirus, rhinovirus, etc. Respiratory syncytial virus (RSV) was first diagnosed by Morris in 1955. It is isolated from the nasal secretions of respiratory tract gorillas and belongs to the genus Pneumovirus of the Paramyxoviridae family, with only one serotype. The incidence of infants under 6 months is the highest, and the infection of infants with pneumonia accounts for 25% of the virus infection and 75% of bronchiolitis. Parainfluenzavirus belongs to the family Paramyxoviridae. There are four types of serotypes: 1, 2, 3, and 4. The main cause of pneumonia is type 3. The adenovirus (adenovirus) is first isolated from the adenoid tissue of the human body. The virus has 41 serotypes that can cause human diseases. Among them, there are types 3, 4, 7, 11, 14 and 21 that are prone to cause pneumonia. Types 3 and 7 are the most common. According to the virus monitoring in Beijing, Shanghai, Guangzhou, Hebei, Xinjiang and other places in recent years, adenovirus and respiratory syncytial virus in children with lower respiratory tract infection account for 1st and 2nd, respectively. Bit. basic knowledge The proportion of sickness: 0.00003% Susceptible people: no specific population Mode of infection: non-infectious Complications: heart failure, shock

Other viral pneumonia causes

Causes:

In addition to the aforementioned common viral pneumonia, human viral pneumonia can be caused by other viruses such as respiratory syncytial virus, parainfluenza virus, adenovirus, rhinovirus and the like.

Pathogenesis

At present, the pathogenesis of viral pneumonia is not fully understood, but the study found that the immune system not only plays a protective role in controlling infection and promoting the recovery of the body, but also participates in the pathogenesis of the virus. The type and quantity of the virus, as well as the host itself, the role of cellular immunity in the host's protective mechanism is particularly important. Therefore, patients with impaired cellular immune function often have serious illness and long course of disease.

Respiratory virus invades the respiratory tract and stimulates the body to release humoral factors. For example, rhinovirus can release bradykinin, IL-1 and IL-8. After RSV infection, histamine, leukotriene C4 and virus-specific IgE can be released. A series of immune reactions, at the same time, viral infection can also change the colony forming ability of the bacteria and increase its adhesion to the airway, reduce the mucociliary clearance rate and reduce the phagocytic ability of the host cells to the bacteria, thus reducing the host immune defense ability It can further contribute to the formation of the following respiratory tract in bacterial infections at normal sterile sites. Because of this, it is estimated that about 53% of community-acquired bacterial pneumonia is infected with the virus, and most viruses have faster antigenic variation, so Humans cannot obtain lasting immunity.

Other viral pneumonia prevention

Prevention should promote breastfeeding, enhance the protective ability of infants with lower respiratory tract infections, do not go to public places during the epidemic period, and prevent the use of high-valent immunoglobulin in infants during the RSV epidemic period. In combination with ribavirin, there is synergy, children It is not advisable to inoculate a respiratory syncytial virus vaccine. The condition of the patients who have used the vaccine is more serious, which may be related to the production of immune complexes caused by IgG antibodies and subsequent infection of respiratory syncytial virus after vaccination, causing local severe allergic reactions. Military oral attenuated enteric-active adenovirus vaccine can reduce the incidence of this disease, but it should not be used in other populations, especially in children, to prevent the infection of parainfluenza virus type I, II, III, and has been proven It is antigenic. However, the preventive effect is not satisfactory.

Other viral pneumonia complications Complications heart failure shock

In severe cases, the three concave signs and the nasal wing fan can be seen. The lungs can smell a wide range of dry and wet voices and wheezing sounds, and can have ARDS, heart failure and acute renal failure, and even shock.

Other symptoms of viral pneumonia Common symptoms Diarrhea, nasal congestion, bloating, nose flaps, dry cough, rash

Viral pneumonia is slow onset, and the condition is generally mild. The course of the disease is more than 2 weeks. Most patients have symptoms of upper respiratory tract infection such as sore throat, nasal congestion, runny nose, fever, headache, and further development of the lesion involves the lung parenchyma. Pneumonia, manifested as cough, mostly paroxysmal dry cough, shortness of breath, chest pain, persistent high fever, infants and children with immunodeficiency, more serious illness, persistent high fever, severe cough, blood stasis, heart palpitations, shortness of breath, Difficulty breathing and cyanosis, viral pneumonia signs are often not obvious, some patients can smell small blisters in the lower lungs, severely visible three concave signs and nose flaps, the lungs can smell a wider range of dry, wet sounds And wheezing, and can appear ARDS, heart failure and acute renal failure, and even shock, more than half of adenovirus pneumonia cases have vomiting, bloating, diarrhea and other gastrointestinal symptoms, generally believed to be related to adenovirus in the intestinal tract About 2/3 of patients with respiratory syncytial virus pneumonia have a hyperthermia, paroxysmal cough, severe asthmatic symptoms, and even red skin Rash, and more audible lung wet rales wheeze, signs of pulmonary consolidation may occur.

Examination of other viral pneumonia

The white blood cell count is generally normal, but it can be slightly higher or lower. When the bacterial infection is secondary, the total number of white blood cells and neutrophils are increased, and the erythrocyte sedimentation rate is often normal. The leukocytes seen by sputum smear are mostly occupied by monocytes. Most of the sputum cultures often have no pathogenic bacteria to grow.

Chest X-ray signs are often not commensurate with the symptoms, often with severe symptoms and no obvious X-ray findings, usually with interstitial pneumonia, showing increased lung texture, small pieces or extensive infiltration, severe cases showing diffuse lungs Nodular infiltration, but large leaf consolidation and pleural effusion are rare. Respiratory syncytial virus pneumonia often has enlarged hilar shadows, thickened lung texture, small patches around the bronchi, or some Qualitary lesions, emphysema is obvious; adenovirus pneumonia has small spots in the lungs, irregular reticular shadows, which can be fused into a sheet-like infiltrating foci. In severe cases, the diffuse infiltration shadows of both lungs are similar to those of acute respiratory distress syndrome. .

Diagnosis and identification of other viral pneumonia

diagnosis

The diagnosis of viral pneumonia mainly depends on the basic characteristics of the virus infection, the clinical manifestations of pneumonia, laboratory tests and X-ray changes, and excludes pneumonia caused by other pathogens. Because of the lack of specific specificity among various types of pneumonia, the final diagnosis It is often necessary to use pathogenic examinations, including virus isolation, serological examination, and detection of viral and viral antigens. Inclusion bodies in the nucleus of respiratory secretions may indicate viral infection, but not necessarily from the lungs. Lower respiratory secretions or lung biopsy specimens for culture and isolation of viruses, immunofluorescence and enzyme-linked immunosorbent assay for the determination of viral antigens in respiratory secretions, the positive rate can reach 85% to 90%, the commonly used method of serological examination is to detect blood Medium specific IgG antibodies, such as complement fixation test, hemagglutination inhibition test, neutralization test, but can only be used as a retrospective diagnosis, and have no early diagnostic value. It has been reported that a single phase of serum is used to detect syncytial virus. The specific IgM antibody of the parainfluenza virus has higher sensitivity and specificity and makes up for The deficiency of double serodiagnosis can be used as an early diagnostic indicator. Serological detection of specific IgA in nasopharyngeal secretion can be diagnosed early, but early specific IgM elevation should not be used as a diagnostic basis for respiratory syncytial virus infection in infants.

Differential diagnosis

The differential diagnosis is mainly related to bacterial pneumonia, mycoplasma, chlamydial respiratory infection and some infectious diseases. It is worth noting that on the basis of respiratory virus infection, the respiratory function and systemic resistance of the respiratory tract are weakened to varying degrees. Therefore, it is easier to secondary bacterial infection in the lungs, among which Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae and hemolytic streptococcus are more common, usually more than 1 to 4 days after the viral infection heat retreat, patients Recurrence of chills and fever, increased respiratory symptoms, cough, phlegm and blood stasis, and bacterial symptoms such as systemic viral symptoms.

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