[A case of severe interstitial pneumonia probably due to Chlamydia pneumoniae].

A 64-year-old male was admitted to our hospital with dyspnea and high fever. The patient had a relative bradycardia and severe hypoxemia. Velcr rales were heard throughout the entire lung fields. Leucocytosis was absent. Chest X-ray showed bilateral diffuse reticular shadows. Corticosteroid pulse therapy and minocycline were introduced on the suspicion of either idiopathic interstitial pneumonia or Chlamydial pneumonia. Subsequently, his symptoms gradually improved. Although the patient had no history of exposure to birds, the titer of complement fixation test for Chlamydia was 1:32 during the acute illness. Microplate immunofluorescence antibody technique proved infection with Chlamydia pneumoniae. We consider this is a rare case of severe pneumonia caused by C. pneumoniae.