Influenza virus pneumonia
Introduction
Introduction to influenza virus pneumonia The onset of the disease often has general flu symptoms, such as sudden onset of illness, cough, sore throat, accompanied by fever, headache, myalgia, discomfort, persistent symptoms, high fever, shortness of breath, cyanosis, cough, hemoptysis, sputum Often very few, but can bring blood. Secondary bacterial infections often occur within 2 weeks of onset, manifested as hyperthermia or once the symptoms are relieved and then aggravated, sputum is purulent, symptoms and signs of bacterial pneumonia appear. The pathogens are mostly Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae and the like. Influenza virus pneumonia is common in chronic heart and lung diseases, chronic metabolic diseases and chronic kidney disease, leading to the deterioration of basic diseases. Chest X-ray examination showed inflammatory infiltration along the lung door toward the periphery. Later, there were scattered flaky and flocculent shadows, which were often distributed in multiple lung fields. In the late stage, fusion changes were observed, mostly concentrated in the lung field. Belt, similar to pulmonary edema, influenza virus pneumonia diagnosis depends on the onset of influenza epidemics and typical clinical manifestations, sputum secretions and lung tissue isolated from influenza virus, and need to exclude bacterial and other pathogen infections such as meningitis, legion Disease, mycoplasmal pneumonia, etc., diagnosis of secondary bacterial pneumonia can be confirmed by bacterial culture of sputum, lung tissue, pleural effusion, blood and other specimens. basic knowledge Sickness ratio: 65% Susceptible people: more common in young people, pregnant women and elderly people over 65 years old Mode of infection: contagious Complications: pneumonia bacteremia meningitis
Cause
Influenza virus pneumonia
(1) Causes of the disease
Influenza virus belongs to the family of Orthomyxoviridae, an RNA virus, which is spherical or elongated, with a diameter of 80-120 nm. Its internal dense core is a nuclear protein composed of 8 fragments of single-stranded RNA and protein. The outer membrane surface has glycoprotein protrusions composed of hemagglutinin and neuraminidase. Hemagglutinin is the main surface antigen of influenza virus. Antibodies against hemagglutinin can neutralize the virus and play a major role in the immunity against influenza virus. Anti-neuraminidase antibodies can limit the release of influenza virus and reduce the occurrence of infection. According to the specificity of nucleoprotein, influenza virus is usually divided into type A, B, C type 3, and type A virus is prone to gene fragment rearrangement and antigen replacement. (shift), it is easy to occur regular antigenic variation, produce new subspecies and varieties, causing a worldwide pandemic; B virus only occurs in point mutations of gene fragments, causing antigenic drift (drift), due to less antigenic variation Only forms variants, so it often causes local outbreaks and small epidemics; type C has no antigenic variation, only appears in scattered form, there were five world influenza pandemics in the 19th century, and the 1918 epidemic caused The death of 20 million people occurred in China from the 1950s to the 1980s. There were more than ten epidemics caused by influenza A virus. In the 1980s, the flu epidemic was mainly caused by sporadic and small outbreaks, and there was no obvious epidemic. Since the 1990s, there have been several outbreaks of influenza B in northern China.
(two) pathogenesis
The population is generally susceptible to influenza virus, and the infection is not long after infection. After the influenza virus-containing droplets are inhaled into the lower respiratory tract, the viral neuraminidase can destroy the neuraminic acid, the glycoprotein receptor is exposed, and the virus hemagglutinin In combination, the virus is adsorbed in the airway epithelial cells of the respiratory tract for replication. Every 4 to 6 hours, a large number of respiratory mucosal epithelial cells are infected, causing degeneration of mucosal epithelium, including particle formation, vacuolation, cell swelling, nuclear pyknosis, etc. The cells eventually necrosis, disintegration, shedding, and the lesions spread downward, causing diffuse lymphocytic infiltration of the bronchial wall, congestion, edema, pulmonary interstitial edema, alveolar red blood cells, monocytes, macrophages and cellulose. Edema fluid, type I and type II cells fall off, transparent membrane formation, serous hemorrhagic bronchopneumonia changes, lung congestion, edema, complicated with bacterial infection, lung leaf consolidation, abscess and interstitial pneumonia, etc. The virus stimulates the body to produce humoral antibodies, local antibodies and cell-mediated immune responses, and protects against infection. It is related to serum anti-hemagglutinin antibody, but IgA secreting antibody also plays a very important role. Cell-mediated immunity includes T lymphocyte proliferation, T lymphocyte cytotoxicity, NK cell activity, and interferon production in disease. It can be detected early that cell-mediated immune responses play a role in disease rehabilitation.
Prevention
Influenza virus pneumonia prevention
Patients should be isolated, prevent and treat cross-infection, and use live attenuated vaccines and inactivated vaccines to prevent them. Because each strain of influenza is often mutated, the vaccine strain should be as close as possible to the strains in the epidemic period. Alkanolamine and rimantadine have certain effects in preventing influenza A. Early application can reduce the incidence of influenza virus pneumonia, but it is not effective for influenza B. Therefore, it is necessary to determine the type of epidemic strain in the early stage of epidemics, and try to prevent Chinese herbal medicine.
Complication
Influenza virus pneumonia complications Complications pneumococcal meningitis
Secondary bacterial pneumonia. Symptoms of upper respiratory tract infection and symptoms of poisoning such as sore throat, nasal congestion, runny nose and fever, headache and body aches. After 24 hours of onset, the condition is rapidly aggravated, and there is high fever, irritability, severe cough, blood stasis, and difficulty breathing. And cyanosis, lungs breath sounds low, covered with dry, wet voice, but no signs of complications of lung consolidation. Pneumococcal will take the opportunity to invade the lungs to cause infection. Infections caused by pneumococci include both "invasive" and "non-invasive" infections. Invasive pneumococcal infection can cause three serious diseases: pneumonia (pulmonary infection), bacteremia (blood infection), and meningitis.
Symptom
Influenza virus pneumonia symptoms common symptoms sore throat high fever retrograde bacterial infection breath sounds low air acute snoring muscle pain hemoptysis
Influenza virus pneumonia is more common in young people, pregnant women and elderly people over 65 years old, especially in the left atrial pressure, such as mitral stenosis, but can also occur in normal people, for direct and serious lung virus infection, the incidence There are often general flu symptoms, such as sudden onset, cough, sore throat, fever, headache, myalgia, discomfort, persistent symptoms, high fever, shortness of breath, cyanosis, cough, hemoptysis, convulsions Very few, but can carry blood, secondary bacterial infection often occurs within 2 weeks of onset, manifested as hyperthermia or symptoms once relieved and then aggravated, sputum turned into purulent, bacterial pneumonia symptoms, signs, pathogens mostly Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae, etc., common in chronic heart, lung disease, chronic metabolic diseases and chronic kidney disease, leading to deterioration of basic diseases, low lung breath sounds during physical examination, in lesions The corresponding parts can smell dry and wet voices, but there are no real signs.
The diagnosis of influenza virus pneumonia depends on the onset and typical clinical manifestations during the influenza epidemic, the secretion of influenza virus from secretions such as sputum and lung tissue, and the exclusion of bacterial and other pathogen infections such as meningitis, Legionnaires' disease, mycoplasma pneumonia, etc. Can be diagnosed, influenza virus can be cultured in tissue cells or yolk sac, isolated from respiratory secretions and lung tissue, usually 48 to 72 hours, using immunofluorescence technology and enzyme-linked immunosorbent assay technology can be used from early tissue culture or nasopharyngeal The virus antigen is detected in the exfoliated cells of the lotion, which is rapid and sensitive, and has early diagnostic value. Other detection methods include hemagglutination inhibition test, complement fixation test, and detection of acute strains using current domestic representative strains or newly isolated strains. The serum antibody in the recovery period and recovery period has a diagnostic value of more than 4 times. The diagnosis of secondary bacterial pneumonia can be confirmed by bacterial culture of specimens such as sputum, lung tissue, pleural effusion, and blood.
Examine
Influenza virus pneumonia check
Other laboratory tests do not help with specific diagnosis. The white blood cell count varies greatly, often low in the early stage, and can be normal or slightly increased in the future. In the case of significant viral or bacterial infection, severe leukopenia can occur when the white blood cell count exceeds At 15 × 109 / L (15000 / l), it is often suggested that there is a secondary bacterial infection.
Chest X-ray examination showed inflammatory infiltration along the lung door toward the periphery. Later, there were scattered flaky, flocculent shadows, often distributed in multiple lung fields, and fusion changes in the late stage, mostly concentrated in the lung field. Belt, similar to pulmonary edema.
Diagnosis
Influenza virus pneumonia diagnosis
Differential diagnosis
It is differentiated from mycoplasmal pneumonia and bacterial pneumonia. It can be manifested as asthma, fever, increased respiratory rate, cough, and cough. Patients with viral pneumonia are older and have more common heart-based diseases than those with bacterial pneumonia. The situation of the disease combined with the flu can occur in all seasons. The peak of the epidemic in northern China generally occurs in winter and spring, while the southern part is popular throughout the year, with peaks occurring in summer and winter. Pay attention to the identification.
