Viral Pulmonary Infections


Community acquired pediatric pulmonary infections are caused by a wide variety of organisms. They are most commonly viral in etiology and present in children less than 5 years old. Bacteria and mycoplasma become more common with increasing age.

Respiratory syncytial virus (RSV) is the most frequently encountered viral agent in the infant and toddler population, usually presenting in the winter months. Parainfluenza, influenza, and adenovirus are also common viral pathogens. Viral infections tend to most severely affect the tracheobronchial tree, resulting in bronchiolitis and bronchitis, with relative sparing of the lung parenchyma.

The role of the radiologist in interpreting a CXR in a patient with a respiratory infection is to determine if it is viral or bacterial. These differences will be elaborated in the following sections.

In summary, viral respiratory infections result in bronchitis, which manifests as peribronchial cuffing, dirty hilum and hyperinflation. Bacterial pneumonia will manifest as focal lobar consolidation with pleural effusion being common.