Medical expert of the article

Pulmonologist

New publications

Viral pneumonias

Alexey Kryvenko, medical expert
Last reviewed: 12.07.2025

All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.

We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.

If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.

Viral pneumonia is caused by various viruses. In adults, the most common cause is influenza A and B viruses, parainfluenza, respiratory syncytial virus, adenovirus. It should be noted once again that primary viral pneumonia, caused directly by viruses, usually occurs in the first 1-3 days, and from the 3rd to the 5th day, pneumonia becomes viral-bacterial.

Influenza pneumonia

This viral pneumonia begins acutely: the body temperature rises rapidly, chills are common, and severe symptoms of intoxication are observed (intense headache, aching bones, muscle pain, loss of appetite, nausea, and even vomiting). Symptoms of damage to the upper respiratory tract (nasal congestion, difficulty breathing through the nose), a dry, paroxysmal cough, and then mucous sputum (sometimes mixed with blood) begins to separate.

Percussion of the lungs shows virtually no changes in percussion sound. A distinct shortening (dullness) of the percussion sound is observed with the development of viral-bacterial pneumonia and the appearance of foci of pulmonary tissue infiltration. However, muffling of the percussion sound over the root of the lung can often be detected. Auscultation of the lungs most often reveals harsh breathing, with the development of viral-bacterial pneumonia - fine bubbling rales and crepitations in various parts of the lungs. Also characteristic is a rapid (within 1-2 days) alternation of foci of harsh or weakened breathing, dry wheezing with foci of crepitations, and wet wheezing. Such dynamism of the auscultatory picture is due to abundant exudate blocking the lumen of the bronchi and the development of dynamic atelectasis.

Due to widespread bronchitis and bronchospasm, severe shortness of breath is possible.

X-ray examination of the lungs reveals predominantly interstitial lesions with increased vascular pattern and peribronchial infiltration. With the development of viral-bacterial pneumonia, signs of damage to the lung parenchyma appear in the form of focal (less often lobar) darkening.

A general blood test reveals leukopenia and lymphopenia.

There is a special form of influenza pneumonia - hemorrhagic pneumonia. It is characterized by a severe course and pronounced symptoms of intoxication. From the first day of the disease, a cough appears with the separation of serous-bloody sputum, the amount of which then increases sharply. High body temperature, shortness of breath, cyanosis are characteristic.

In the following days, against the background of high body temperature and pronounced dyspnea, respiratory failure increases, pulmonary edema and hypoxemic coma develop. Hemorrhagic influenza pneumonia often ends in death.

Pneumonia caused by other viruses

The clinical picture of pneumonia caused by other viruses (parainfluenza, adenoviruses, respiratory syncytial virus ) is mainly manifested by symptoms similar to influenza pneumonia. However, with pneumonia caused by the parainfluenza virus, fever is less pronounced, tracheitis is more often observed, and slow resolution of the inflammatory process in the lungs is characteristic.

Adenovirus pneumonia is accompanied by catarrhal tracheobronchitis with prolonged cough, often hemoptysis, nasopharyngitis, persistent fever, enlargement and soreness of the lymph nodes in the neck, radiologically small foci of darkening and sometimes enlargement of the lymph nodes in the root of the lung. Adenovirus infection is also characterized by eye damage in the form of conjunctivitis. As a rule, pneumonia in adenovirus infection is viral-bacterial.

Pneumonia caused by the respiratory syncytial virus is characterized by a high body temperature for 7-10 days, chest pain, wet and dry wheezing in various parts of the lungs, and is accompanied by symptoms of nasopharyngitis. X-ray examination of the lungs reveals an increase in the pulmonary pattern, and it is possible to identify areas of compaction of the lung tissue.

Where does it hurt?

Chest pain

Chest pain in children

What's bothering you?

High fever in a child

Diagnostic criteria for viral pneumonia

When diagnosing viral pneumonia, the following points must be taken into account:

the presence of an epidemiological situation regarding influenza and other acute respiratory diseases;
characteristic clinical manifestations of influenza or other acute respiratory diseases;
predominantly interstitial changes in the lungs on X-ray examination;
detection of the virus in mucus of the pharynx, nose, nasopharyngeal swabs using the immunofluorescence method with monoclonal antibodies;
an increase in antibody titers in the blood of patients to the corresponding viruses by 4 times or more 10-14 days from the onset of the disease (retrospective diagnosis of viral infection).