Influenza and Viral Pneumonia

Abstract

Influenza and other respiratory viruses are commonly identified in patients with community-acquired pneumonia, hospital-acquired pneumonia, and in immunocompromised patients with pneumonia. Clinically, it is difficult to differentiate viral from bacterial pneumonia. Similarly, the radiological findings of viral infection are nonspecific. The advent of polymerase chain reaction testing has enormously facilitated the identification of respiratory viruses, which has important implications for infection control measures and treatment. Currently, treatment options for patients with viral infection are limited, but there is ongoing research on the development and clinical testing of new treatment regimens and strategies.

Keywords: Antiviral; Epidemiology; Influenza; Pneumonia; Polymerase chain reaction; Symptoms; Virus.

Fig. 1

Number of studies according to most commonly identified viral pathogen. RSV, respiratory syncytial virus.

Fig. 2

Proportion of pneumonia and associated outcomes in patients admitted to the hospital with influenza infection.

Fig. 3

Probability of influenza according to presence of combined cough and fever in patients presenting during influenza season (A) and outside the influenza season (B).

Fig. 4

Chest radiograph and computed tomography of the chest of a 42-year-old male patient admitted with pneumonia and 2009 H1N1 influenza infection leading to acute respiratory failure. Chest radiograph (A) reveals diffuse consolidation, and the computed tomography of the chest (B) reveals bilateral patchy ground-glass opacities and dense consolidation in the dorsal areas.

Fig. 5

Computed tomography of the chest revealing diffuse ground-glass opacities and small bilateral pleural effusion in a 62-year-old female patient with respiratory syncytial virus infection who developed pneumonia and acute respiratory distress syndrome.

Fig. 6

Treatment approach in patients presenting with community-acquired pneumonia.

Fig. 7

Viral pathogen-directed therapy. CMV, cytomegalovirus; HSV, herpes simplex virus; IV, intravenous; RSV, respiratory syncytial virus; VZV, varicella zoster virus.