Viral pneumonia

Alternative names:

pneumonia - viral

Definition:

Inflammation of the lungs caused by a viral infection. See also respiratory syncytial virus (RSV) and influenza.

Causes, incidence, and risk factors:

Pneumonia is a common serious illness that affects 1 out of 100 people annually. Viral pneumonia can range in seriousness from a mild illness to moderately severe (respiratory syncytial virus) or sometimes fatal (Hantavirus pulmonary disease). Influenza, parainfluenza, adenovirus, rhinovirus, herpes simplex, and cytomegalovirus may cause pneumonia. Viral infections are usually diagnosed when there are no bacterial organisms in a sputum culture (because it is difficult to isolate viruses in culture). Respiratory syncytial virus (RSV) and influenza are two of the more common viral infections that can cause pneumonia. Annual epidemics of both viruses occur with incubation periods between 1 and 4 days. The infections affect young children and the elderly more severely. Infants with congenital heart disease are at risk for severe or fatal RSV infection. The incidence is 2 out of 10,000 people.