Clinical features of Q fever pneumonia.

The aim of the study was to assess the clinical features of Q fever pneumonia in Japan. Four cases of Q fever pneumonia (a female aged 21 and males aged 53, 74 and 87 years) who were diagnosed using the PanBio ELISA test kit, were assessed and their clinical features are described. The frequency of Q fever pneumonia among our cases of community-acquired pneumonia was 1.4% (4/284). A 21-year-old female had a typical case of the disease with (i) a history of owning a cat, (ii) onset with fever and dry cough, (iii) multiple soft infiltrative shadows on CXR, (iv) a normal white blood cell count, and (v) good response to clarithromycin. The pneumonias in the other three cases were considered mixed infections with bacteria such as Streptococcus pneumoniae and Haemophilus influenzae. Their clinical features included the following: (i) an elderly person with an underlying disease, (ii) onset with fever and purulent sputum, (iii) coarse crackles on auscultation, (iv) infiltrative shadows and pleural effusion on CXR, (v) increased white blood cells with elevated BUN and hyponatraemia, and (vi) modest responses to combined therapy with carbapenem and minocycline. Our observations suggest that two types of pneumonia caused by Coxiella burnetti exist; one with the usual features of atypical pneumonia, and the other presenting with the clinical features of bacterial pneumonia in the elderly due to mixed bacterial infection.