Viral pneumonia is inflammation of the lung parenchyma due to lower respiratory tract viral infection, most commonly influenza virus, parainfluenza virus, respiratory syncytial virus, adenovirus, or metapneumovirus. The exact pathophysiology is dependent on the organism, but disruption of normal epithelial cell function and loss of mucociliary clearance is common.
Clinical manifestations may include upper respiratory symptoms, conjunctivitis, and rhinitis in association with fever, nonproductive cough, and malaise.
Physical examination findings often reveal tachypnea, diffuse rales, and wheezes and may reveal cyanosis and hypoxemia.
Patients at higher risk for development of viral pneumonia are those with underlying cardiopulmonary disease, eg, valvular heart disease or chronic obstructive pulmonary disease, and those who are immunocompromised or pregnant.
Complications include development of acute respiratory distress syndrome or secondary bacterial pneumonia, which usually occurs 2-14 days after an improving clinical course with recurrence of fever, cough, and dyspnea.
