The syndrome of afebrile pneumonitis in infants is a relatively common disease that has gone by myriad names in the medical literature. Appellations for this clinical syndrome have included atypical pneumonia, infantile pneumonitis, interstitial pneumonia, viral pneumonia, or nonbacterial pneumonia.<sup>5 Boyer K.M., Cherry J.D. Non-bacterial pneumonia Pediatric Infectious Diseases Philadelphia: WB Saunders (1992).  254-264

Cliccare qui per andare alla sezione Riferimenti</sup> Despite this confusion of names, most clinicians are familiar with the clinical picture of a patient with a pneumonia that is not a typical lobar or lobular process as seen with pyogenic bacteria such a Streptococcus pneumoniae. For this article, afebrile pneumonia is defined as a pneumonitis with the following:

This definition is intended to apply to the majority of children, but clearly there are exceptions. For instance, some infants with an atypical pneumonia present with fever. Terms that imply a etiologic agent such as nonbacterial pneumonia should be avoided because bacterial agents are actually common causes of afebrile pneumonia, as is discussed. This article focuses mainly on afebrile pneumonia in infants, in particular, those younger than 6 months of age. Comparison are made to pneumonia in older children. Etiologic agents are discussed as well as the clinical presentations, diagnosis, and treatment of afebrile pneumonia in infancy.