In normal hosts:

* Influenza is most common cause of viral pneumonia
* On radiographs, there is poorly defined, patchy airspace consolidation that rapidly becomes confluent
* On CT, there is ground-glass opacities mixed with consolidation
* Pleural effusion is rare
* In a study of 8 hospitalized patients infected with Avian Influenza (H5N1), chest radiographs showed extensive opacities with segmental and multifocal distribution. Most opacities were in lung bases. No effusion or hilar lymphadenopathy.

In immunocompromised hosts:

* Cytomegalovirus (CMV) and herpesvirus are most common
* CMV is actually a member of herpesvirus family
* On imaging, there is mixed interstitial and airspace opacity that could range from ground-glass opacity, consolidation, nodules, poorly defined centrilobular nodules, bronchial dilatation and septal thickening

Our case is a 50-year-old man, known lymphoma, who developed CMV pneumonia.

1. Kim EA, Lee KS, Primack SL, et al. Viral pneumonias in adults: radiologic and pathologic findings. Radiographics 2002;22:S137-S149.
2. Bay A, Etlik O, Oner AF, et al. Radiological and clinical course of pneumonia in patients with avian influenza H5N1. Eur J Radiol 2007;61:245-250.

Source: Case submitted by RadiologyinThai, Dr. Rathachai Kaewlai