ROENTGENOGRAPHIC FINDINGS OF PNEUMONIA CAUSED BY CHLAMYDIA-PNEUMONIAE- COMPARISON WITH STREPTOCOCCUS-PNEUMONIA

Background: Pneumonia caused by Chlamydia pneumoniae or Streptococcus pneumoniae cannot be reliably differentiated by clinical signs or symp toms. Objective: To find differences in the roentgenographic patterns of community-acquired pneumonia caused by C pneumoniae, S pneumoniae, or both in hospitalized patients during a C pneumoniae epidemic in Fin land. Methods: The patients were divided into 3 groups: 24 patients wi th serologic evidence of C pneumoniae only; 8 patients with combined C pneumoniae and S pneumoniae infection; and 13 patients with infection caused by S pneumoniae only. The chest roentgenograms obtained on adm ission to the hospital, during the hospital stay, and at follow-up vis its were reevaluated by one of us (S.L.) who was unaware of the causat ive organism. In the final study groups, other causes of community-acq uired pneumonia were excluded by a large pattern of microbiological me thods. Results: Bronchopneumonia was observed in 21 (88%) of the group with C pneumoniae and 10 (77%) of the group with S pneumoniae (P=.67) . Lobar or sublobar (air space) pneumonia was seen in 7 (29%) of the p atients with C pneumoniae compared with 7 (54%) with pneumonia caused by S pneumoniae. In the combined group, bronchopneumonia was seen as f requently as in the group with C pneumoniae, and air-space involvement was seen as frequently as in the group with S pneumoniae. The pneumon ic shadowing was usually unilateral and in the lower lobes in all grou ps. Of the patients in the C pneumoniae group, 17% had residual abnorm alities at follow-up visits.