Viral pneumonia

Introduction to viral pneumonia Viral pneumonia is a bronchial pneumonia caused by a variety of viral infections, which occurs mostly in winter and spring. Clinical manifestations are generally mild. The main symptoms are dry cough, fever, difficulty breathing, purpura and loss of appetite, less signs of lungs, normal or slightly elevated white blood cell count. Chest X-ray examination has patchy inflammatory shadows, and the general course of disease is about 1-2 weeks. Viral pneumonia occurs mostly in winter and spring, and can spread epidemics or outbreaks. In non-bacterial pneumonia, viral infection accounts for about 25% to 50%. Most of the patients are children. Adults are relatively rare. In recent years, immunosuppressive drugs have been widely used. The incidence of cancer, organ transplantation, and AIDS is increasing year by year. Herpes simplex virus, varicella-zoster virus, cytomegalovirus, etc. can cause severe pneumonia. Viral pneumonia is an inhalation infection. The droplet infection is mainly caused by the downward spread of upper respiratory virus infection. basic knowledge The proportion of illness: 10% Susceptible people: no special people Mode of infection: non-infectious Complications: bacterial pneumonia Myocarditis

Cause of viral pneumonia

Virus infection (35%):

Viral pneumonia is a bronchopneumonia caused by a variety of viral infections, usually influenza virus, followed by parainfluenza, cytomegalovirus, adenovirus, rhinovirus, coronavirus and certain enteroviruses, such as Coxsackie , Echo virus, etc., as well as chickenpox, rubella, measles virus, respiratory syncytial virus.

Infection begins with the upper respiratory tract, the airway epithelium is extensively damaged, the mucosa is ulcerated, the fibrin membrane is covered, the airway's defense function is reduced, and bacterial infection is easily caused. The immune status is low, and the fungus, the protozoa, especially the card Pneumocystis infection, simple viral pneumonia caused by interstitial pneumonia, alveolar septum with large mononuclear cell infiltration, alveolar edema, covered with transparent membrane containing plasma protein and fibrin, so that alveolar mucosal distance thickened, pneumonia For focal or extensive diffuse, or even consolidation, viral inclusion bodies can be seen in alveolar cells and macrophages, and there are exudates in the bronchioles. Pulmonary fibrosis and even nodular calcification can be left after the lesions are absorbed.

Route of infection (30%):

In recent years, due to the widespread use of immunosuppressive drugs in cancer, organ transplantation, and the increasing number of AIDS cases, herpes simplex virus, varicella-zoster virus, cytomegalovirus, etc. can cause severe pneumonia. Viral pneumonia is an inhalation infection caused by human-to-human droplets, mainly caused by the spread of upper respiratory virus infection, often accompanied by tracheal-bronchitis, and livestock such as horses and pigs sometimes have some epidemic Cold virus, occasionally contact with infection. The fecal infection is seen in the enterovirus, and the respiratory syncytial virus is transmitted through the dust. Cases of organ transplantation can cause blood transfusions through multiple blood transfusions, even in the donor's organs. Viral pneumonia spread by blood is not associated with tracheal-bronchitis.

Viral pneumonia prevention

Viral pneumonia occurs mostly in winter and spring, and can spread epidemics or outbreaks. In non-bacterial pneumonia, viral infection accounts for about 25% to 50%. Most of the patients are children. Adults are relatively rare. In recent years, immunosuppressive drugs have been widely used. The incidence of cancer, organ transplantation, and AIDS is increasing year by year. Herpes simplex virus, varicella-zoster virus, cytomegalovirus, etc. can cause severe pneumonia. Viral pneumonia is an inhalation infection. The droplet infection is mainly caused by the downward spread of upper respiratory virus infection, often accompanied by tracheal-bronchitis, livestock such as horses, pigs, etc. sometimes with some influenza virus, occasionally contact infection, fecal infection In the case of enteroviruses, respiratory syncytial virus is transmitted through dust. Organ transplants can cause blood transfusions through multiple blood transfusions, even in the donor's organs. The viral pneumonia spread by blood is not associated with tracheal-bronchitis.

After the virus infection, the antibody appears later, and it has little effect on the control of infection. Interferon has a protective effect on the virus infection of susceptible cells, preventing the development of the disease and preventing its dissemination. Cellular immunity has a controlling effect on certain viruses, such as The cellular immunodeficiency of leukemia or Hodgkin's disease is very susceptible to herpes and varicella virus, but it is not susceptible to other viruses. At present, attenuated measles live vaccine has been widely vaccinated in infants and young children. Measles is extremely rare, measles Pneumonia is even rarer.

Viral pneumonia complications Complications, bacterial pneumonia, myocarditis

Secondary bacterial pneumonia: The most common pathogens are Streptococcus pneumoniae, Staphylococcus aureus or Haemophilus influenzae. The patient's condition is gradually worsening, or the clinical symptoms are further aggravated after a temporary improvement, coughing, coughing, and appearance. Signs of lung consolidation, X-ray found flaky and patchy shadows in the lungs, Reye syndrome, myocarditis: It has been reported that influenza virus pneumonia can be complicated by myocarditis.

Symptoms of viral pneumonia Common symptoms Headache dry cough high heat fatigue nodular lung texture thickening azotemia hilar widening around the lower lobe of the lungs...

The clinical manifestations of this disease are generally mild, similar to the symptoms of mycoplasmal pneumonia, slow onset, headache, fatigue, fever, cough, and cough a small amount of sticky phlegm, signs often absent, X-ray examination of lung inflammation is spotted, Shape or uniform shadow, the total number of white blood cells can be normal, reduced or slightly increased, the course of disease is generally 1 to 2 weeks, in patients with immunodeficiency, viral pneumonia is often more serious, persistent high fever, palpitations, shortness of breath, cyanosis, extreme exhaustion May be associated with shock, heart failure and azotemia, due to alveolar interstitial and alveolar edema, severe respiratory distress syndrome may occur, physical examination may have wet rales, X-ray examination shows diffuse nodular infiltration, more Seen in two 2/3 lung fields.

Examination of viral pneumonia

1, blood routine, urine routine, fecal routine.

2. X-ray inspection.

3, body fluid immunoassay.

4, liver function tests, renal function tests.

5. Bacterial culture.

6, CT examination.

7, endoscopy.

Diagnosis and identification of viral pneumonia

diagnosis

First, medical history, symptoms:

The onset is slow. In the early stage, there are many dry upper respiratory symptoms such as dry throat, sore throat, sneezing, runny nose, fever, headache, anorexia and body aches. The lesion may involve cough (mostly paroxysmal dry cough) and chest pain. Symptoms such as shortness of breath, medical history should pay special attention to the presence or absence of immunodeficiency or immunosuppression.

Second, physical examination found:

Signs are not obvious, sometimes you can smell small blisters in the lower part of the lungs.

Third, auxiliary inspection:

(1) X-ray chest radiograph, the two lungs are mesh-like shadows, the lung texture is thickened and blurred, and in severe cases, diffuse nodular shadows can be seen in the lower lungs, and the consolidation is rare.

(B) blood test: white blood cell count is generally normal, but also slightly higher or lower, white blood cell count and neutrophils can increase when secondary bacterial infection.

(3) Pathogen examination: It is difficult to carry out virus culture and it is not easy to carry out routinely. The sputum smear of pneumonia patients only find scattered bacteria and a large number of nucleated cells, or can not find pathogenic bacteria, and the possibility of viral pneumonia should be suspected.

(4) Serological examination: double serum in the acute phase and recovery phase, complement fixation test, neutralization test or serum inhibition test antibody titer increased by 4 times or more has a diagnostic significance. In recent years, serum-specific virus-specific IgM antibodies have been used. It can help early diagnosis, immunofluorescence, enzyme-linked immunosorbent assay, enzyme labeling method, horseradish peroxidase-anti-horse root peroxidase method, etc., for virus-specific rapid diagnosis.

Differential diagnosis

Bacterial pneumonia, SARS, AP, influenza virus pneumonia, tuberculosis, pulmonary fungal pneumonia and other diseases.

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