Febrile infants less than 3 months old: value of chest radiography.

In the febrile infant less than 3 months old, a chest radiograph is commonly obtained to identify the cause of the fever. The purpose of this study was to evaluate the necessity of obtaining chest radiographs in this population. The clinical records and chest radiographs of 192 febrile infants (greater than 100.5 degrees F, rectal) were reviewed. Nineteen patients had signs of respiratory distress; seven had positive findings on chest radiographs. Of the 173 patients without signs of respiratory distress, five had positive findings on chest radiographs. When chest radiography was considered the gold standard for the presence or absence of pneumonia, findings of respiratory distress on physical examination had a sensitivity of 58% and a specificity of 93% for the detection of pneumonia. The prevalence of positive findings on chest radiographs in febrile infants less than 3 months old was 6%. A chest radiograph should be obtained in febrile infants only when signs of respiratory distress are present.