Chlamydia infection

C. psittaci commonly infects birds and mammals from which humans acquire the disease psittacosis. Clinically patients may have a mild fever and headache. Occasionally severe fever and chills as well as severe respiratory symptoms are noted. Radiographically a variety of abnormalities have been described including scattered hazy lung opacities, lobar consolidation, and perihilar and lower lobe linear and reticular opacities. Occasionally, hilar and mediastinal lymphadenopathy and pleural effusions occur. Slow improvement follows antibiotic therapy.

C. pneumoniae is a frequent cause of mild community-acquired pneumonia. Spread from human to human via droplet transmission is suspected. Radiographically, homogeneous opacities in single or multiple lobes as well as small effusions are observed.

C. trachomatis is more commonly a cause of conjunctivitis than pneumonia in newborns and infants. The chest film demonstrates bilateral heterogeneous or homogeneous opacities with overinflation of lungs. In immunosuppressed adults C. trachomatis may produce similar abnormalities.

Treatment with erythromycin for C. psittaci and C. pneumoniae is generally effective.

PGO