What Is Viral Pneumonia?

Viral pneumonia is inflammation of the lungs caused by the upper respiratory tract virus infection, which spreads downward. The disease can occur all year round, but most of them occur in winter and spring, and can be outbreaks or sporadic. Clinical manifestations are fever, headache, general soreness, dry cough, and pulmonary infiltration. The occurrence of viral pneumonia is related to the virulence of the virus, the route of infection, the age of the host, and the state of immune function. The pediatric incidence is generally higher than that of adults.

Basic Information

Visiting department

Respiratory Medicine

Multiple groups

child

Common locations

lung

Common causes

Parainfluenza virus, cytomegalovirus, adenovirus and other viral infections

Common symptoms

Fever, headache, general soreness, dry cough, and lung infiltration

way for spreading

Have

Causes of viral pneumonia

Viral infections account for 90% of acute respiratory infections, and viral infections are mainly from the upper respiratory tract, including common cold, pharyngitis, laryngo-tracheobronchiolitis, bronchiolitis, infantile herpes angina, and epidemic chest pain. Pneumonia-causing viruses are rare, of which influenza viruses are common, others are parainfluenza virus, cytomegalovirus, adenovirus, rhinovirus, coronavirus, and certain enteric viruses, such as Coxsackie and Echovirus And other viruses such as herpes simplex, chickenpox-zoster, rubella, and measles. Infants and young children also often develop pneumonia from respiratory syncytial virus infection. Viral pneumonia occurs mostly in the winter and spring seasons, and can spread epidemic or outbreak. In nonbacterial pneumonia, viral infections account for 25% to 50%, and most patients are children, and adults are relatively rare.

In recent years, immunosuppressive drugs have been widely used in tumors, organ transplants, and the number of AIDS patients has increased year by year. Herpes simplex virus, chickenpox-zoster virus, cytomegalovirus, etc., can cause severe pneumonia. Viral pneumonia is an inhalation infection. It is transmitted by droplets from person to person. It is mainly caused by the downward spread of upper respiratory virus infection. It is often accompanied by tracheobronchitis. Domestic animals such as horses and pigs sometimes have some epidemic. Cold virus, occasional contact infection. Fecal oral infection is seen in enteroviruses, and respiratory syncytial virus is transmitted through dust. Organ transplant cases can be caused by multiple blood transfusions and even donor organs. Hematogenous viral pneumonia is not associated with tracheobronchiolitis.

Clinical manifestations of viral pneumonia

The clinical manifestations of this disease are generally mild, similar to the symptoms of mycoplasma pneumonia. Onset is slow with headache, fatigue, fever, cough, and a small amount of sticky sputum. Signs are often absent. X-ray examination of the lungs showed spotty, flaky, or even shadows. The total number of white blood cells can be normal, decreased or slightly increased. The course of disease is usually 1 to 2 weeks. In patients with immune deficiency, viral pneumonia is often more severe, with persistent high fever, palpitations, shortness of breath, cyanosis, extreme failure, and can be accompanied by shock, heart failure, and azotemia. Due to the alveolar interstitial and alveolar edema, respiratory distress syndrome can occur in severe cases. Physical examination may have wet rales. X-ray examination showed diffuse nodular infiltration, more common in two 2/3 lung fields.

Viral pneumonia test

Etiological examination

Virus culture is difficult and it is not easy to carry out routinely. Sputum smears of patients with pneumonia only found scattered bacteria and a large number of nucleated cells, or no pathogens could be found. The possibility of viral pneumonia should be suspected.

2. Serological examination

In the acute and recovery phases of serum, the antibody titer of the complement binding test, neutralization test or serum inhibition test is increased 4 times or more. In recent years, serum-specific IgM antibodies have been used to monitor the virus for early diagnosis. Immunofluorescence, enzyme-linked immunosorbent assay, enzyme-labeled histochemical method, horseradish peroxidase-anti-horseradish peroxidase method, etc. can be used for rapid virus-specific rapid diagnosis.

3. White blood cells

The count is normal, slightly high, or low, and the erythrocyte sedimentation is usually in the normal range. The white blood cells seen in the sputum smear are mostly monocytes, and the sputum culture often does not grow pathogenic bacteria.

4. Chest X-ray

Examination showed increased lung texture, small patch infiltration or extensive infiltration. In severe cases, diffuse nodular infiltration of both lungs was observed, but those with large lobe consolidation and pleural effusion were rare. The cause of viral pneumonia is different, and its X-ray signs have different characteristics.

Viral pneumonia diagnosis

The diagnosis of viral pneumonia is based on clinical symptoms and x-ray changes, and pneumonia caused by other pathogens is excluded. Confirmation depends on pathogenic tests, including virus isolation, serological tests, and detection of viral antigens. Inclusion bodies in the nucleus of respiratory tract secretions may indicate viral infection, but they do not necessarily come from the lungs, and further collection of lower respiratory tract secretions or lung biopsy specimens are required for culture to isolate the virus. The common method for serological examination is to detect specific IgG antibodies, such as complement binding test, hemagglutination inhibition test, and neutralization test, but it can only be used as a retrospective diagnosis and has no early diagnostic value.

Viral pneumonia treatment

The main treatment is symptomatic treatment, bed rest, air circulation in the room, isolation and disinfection, and prevention of cross infection. Give enough vitamins and protein, drink plenty of water and eat soft food a few times, intravenous infusion and oxygen as appropriate. Keep the airway unobstructed and remove the upper airway secretions in time. In principle, antibiotics should not be used to prevent secondary bacterial infections. Once bacterial infections have been identified, sensitive antibiotics should be selected in a timely manner.

Currently, more effective virus inhibitors have been proven: Ribavirin has a broad-spectrum antiviral function, including respiratory syncytial virus, adenovirus, parainfluenza virus, and influenza virus. Acyclovir is a chemically synthesized antiviral drug, which has the characteristics of broad spectrum, potency and fast onset. Clinically used for herpes virus, chickenpox virus infection. Especially for immunodeficiency or immunosuppressants should be applied as soon as possible. Ganciclovir is an acyclic guanosine analog, which inhibits DNA synthesis. It is mainly used for cytomegalovirus infection. Oseltamivir is a neuraminidase inhibitor, which has a good effect on influenza A and B viruses and has a low incidence of drug resistance. Adenosine is a purine nucleoside compound, which has a wide range of antiviral effects. It is mostly used to treat herpes virus and chickenpox virus infection in immunodeficiency patients. Amantadine is a synthetic amine drug, which can prevent certain viruses from entering human cells and reducing fever. Clinically used for infections such as influenza virus.