Viral pneumonia is an infectious lesion of the lower respiratory tract caused by respiratory viruses (influenza, parainfluenza, adenoviruses, enteroviruses, respiratory syncytial virus, etc.). Disease occurs acutely with a sudden increase in body temperature, chills, intoxication syndrome, wet cough, pleural pain, respiratory failure. The diagnosis takes into account physical, radiological and laboratory data, the connection of pneumonia with a viral infection. Therapy is based on the appointment of antiviral and symptomatic agents.
J12 Viral pneumonia, not classified elsewhere
Viral pneumonia is an acute inflammation of the respiratory parts of the lungs caused by viral pathogens, occurring with a syndrome of intoxication and respiratory disorders. In childhood, disease accounts for about 90% of all cases of pneumonia. Bacterial pneumonia predominates in the structure of adult morbidity, and viral ones account for 4-39% of the total (people over 65 years of age are more likely to get sick). The frequency of viral pneumonia is closely related to epidemiological outbreaks of acute respiratory viral infections – their rise occurs in the autumn-winter period. In pulmonology, primary viral pneumonia is distinguished (interstitial with a benign course and hemorrhagic with a malignant course) and secondary (viral-bacterial pneumonia – early and late).
Viral pneumonia causes
The spectrum of pathogens of viral pneumonia is extremely wide. The most common etiological agents are respiratory viruses of influenza A and B, parainfluenza, adenovirus. Persons with immunodeficiency are more susceptible than others to viral pneumonia caused by the herpes virus and cytomegalovirus. Pneumonia initiated by enteroviruses, hantavirus, coronavirus, metapneumovirus, Epstein-Barr virus are less often diagnosed. SARS-associated coronavirus is the causative agent of severe acute respiratory syndrome (SARS), better known as atypical pneumonia. In young children, viral pneumonia is often caused by respiratory syncytial virus, as well as measles and chickenpox viruses.
Primary viral pneumonia manifests in the first 3 days after infection, and after 3-5 days bacterial flora joins, and pneumonia becomes mixed – viral-bacterial. People with an increased risk of disease include young children, patients over 65 years of age, people with weakened immunity, cardiopulmonary pathology (heart defects, severe arterial hypertension, coronary heart disease, chronic bronchitis, bronchial asthma, emphysema of the lungs) and other concomitant chronic diseases.
Transmission of viruses is carried out by airborne droplets during breathing, talking, sneezing, coughing; a contact-household route of infection through contaminated household items is possible. Viral particles penetrate into the respiratory parts of the respiratory tract, where they are adsorbed on the cells of the bronchial and alveolar epithelium, cause its proliferation, infiltration and thickening of the interalveolar septa, circular cell infiltration of peribronchial tissue. In severe forms of viral pneumonia, hemorrhagic exudate is found in the alveoli. Bacterial superinfection significantly aggravates the course of viral pneumonia.
Viral pneumonia symptoms
Depending on the etiological agent, viral pneumonia can occur with varying degrees of severity, complications and outcomes. Pneumonia usually joins from the first days of the course of ARVI.
Thus, the defeat of the respiratory parts of the respiratory tract is a frequent companion of adenovirus infection. The onset of pneumonia in most cases is acute, with a high fever (38-39 °), cough, severe pharyngitis, conjunctivitis, rhinitis, painful lymphadenopathy. The temperature with adenovirus pneumonia lasts for a long time (up to 10-15 days), differs in large daily fluctuations. Characterized by frequent, short cough, shortness of breath, acrocyanosis, various-sized wet wheezing in the lungs. In general, adenovirus pneumonia is distinguished by long-term preservation of clinical and radiological changes, a tendency to recurrent course and complications (pleurisy, otitis media).
The incidence of viral pneumonia against the background of influenza increases significantly during epidemics of respiratory infection. In this case, against the background of typical symptoms of acute respiratory viral infections (fever, severe weakness, myalgia, catarrh of the upper respiratory tract), there is noticeable shortness of breath, diffuse cyanosis, cough with rusty sputum, wheezing in the lungs, chest pain when inhaling. Children have general toxicosis, anxiety, vomiting, convulsions, meningeal signs may occur. Influenza pneumonia is usually bilateral in nature, as evidenced by auscultative data and X-ray picture (focal darkening in both lungs). Mild cases of disease caused by the influenza virus are characterized by moderate symptoms and ends in recovery.
Parainfluenza pneumonia more often affects newborns and young children. It has a small focal (less often drain) character and proceeds against the background of catarrhal phenomena. Respiratory disorders and intoxication syndrome are moderately pronounced, body temperature usually does not exceed subfebrile values. Severe forms of viral pneumonia with parainfluenza in children occur with severe hyperthermia, seizures, anorexia, diarrhea, hemorrhagic syndrome.
A feature of respiratory syncytial pneumonia is the development of severe obstructive bronchiolitis. The defeat of the lower respiratory tract is marked by an increase in body temperature to 38-39 ° C, deterioration of the general condition. Due to spasm and blockage of small bronchi with mucus and desquamated epithelium, breathing becomes sharply difficult and rapid, cyanosis of the nasolabial and periorbital areas develops. Cough is frequent, moist, but due to the increased viscosity of sputum, it is unproductive. With this type of viral pneumonia, attention is drawn to the discrepancy between intoxication (moderately expressed) and the degree of respiratory insufficiency (extremely pronounced).
Enterovirus pneumonia, the causative agents of which are Coxsackie and ESNO viruses, proceed with scant physical and radiological data. In the clinical picture, concomitant meningeal, intestinal, and cardiovascular disorders that complicate diagnosis come to the fore.
Severe forms of viral pneumonia occur with constant high fever, respiratory failure, collapse. Among the complications, influenza encephalitis and meningitis, otitis, pyelonephritis are frequent. The addition of a secondary bacterial infection often leads to the appearance of lung abscesses or pleural empyema. A fatal outcome is possible during the first week of the disease.
A thorough study of the anamnesis, epidemiological situation, assessment of physical and laboratory radiological data will help to correctly recognize the etiological form of pneumonia and identify the causative agent. Viral pneumonia usually develops during periods of epidemic outbreaks of acute respiratory viral infections, occurs against the background of catarrhal syndrome, accompanied by signs of respiratory failure of varying severity. Small bubbly wheezes are heard auscultatively in the lungs.
Lung radiography reveals an increased interstitial pattern, the presence of fine-focal shadows more often in the lower lobes. To confirm the viral etiology of pneumonia, the study of sputum, tracheal aspirate or bronchial flushing waters by the method of fluorescent antibodies helps. In the blood in the acute period, there is a fourfold increase in the titers of AT to the viral agent. A comprehensive assessment of objective data by a pulmonologist will make it possible to exclude atypical, aspiration pneumonia, obliterating bronchiolitis, infarct pneumonia, bronchogenic cancer, etc.
Viral pneumonia treatment
Hospitalization is indicated only for children under 1 year old, patients of the older age group (over 65 years old), as well as those with severe concomitant diseases (COPD, heart failure, diabetes mellitus). Patients are prescribed bed rest, copious drinking, fortified, high-calorie nutrition.
Etiotropic therapy is prescribed depending on the viral pathogen: remantadine, oseltamivir, zanamivir – for influenza pneumonia, acyclovir – for herpes viral pneumonia, ganciclovir – for cytomegalovirus infection, ribavirin – for respiratory syncytial pneumonia and hantavirus infection, etc. Antibacterial agents are added only with the mixed nature of pneumonia or the development of purulent complications. Expectorants and antipyretics are used as symptomatic treatment. In order to facilitate the discharge of sputum, medicinal inhalations and drainage massage are carried out. With severe toxicosis, intravenous infusion of solutions is carried out; with the development of respiratory insufficiency, oxygen therapy is performed.
Prognosis and prevention
In most cases, viral pneumonia ends with recovery within 14 days. 30-40% of patients have a prolonged course of the disease with the preservation of clinical and radiological changes for 3-4 weeks, followed by the development of chronic bronchitis or chronic pneumonia. Morbidity and mortality from disease are higher among young children and elderly patients.
Prevention of disease is closely related to the immunization of the population, first of all, preventive seasonal vaccination against influenza and the most dangerous childhood infections. Nonspecific measures to strengthen immunity include hardening, vitamin therapy. During periods of acute respiratory viral infections, it is necessary to observe personal precautions: if possible, exclude contact with patients with respiratory infections, wash hands more often, ventilate the room, etc. Especially these recommendations concern the contingent of increased risk for the development and complicated course of viral pneumonia.
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