Fusobacterium nucleatum Pleural Empyema in a Patient with Progressive Rheumatoid Arthritis and Immunosuppression.

Fusobacterium nucleatum is an anaerobic oral commensal organism that is often associated with inflammatory bowel disease, adverse pregnancy outcomes, respiratory tract infections, and Lemierre's syndrome. Rheumatoid arthritis is often associated with pleuropulmonary manifestations including noninfectious pleural effusions and interstitial lung disease. We present a case of a 47-year-old man with progressive rheumatoid arthritis on immunosuppressive therapy who was found to have a left-sided pleural effusion, thought secondary to possible pneumonia, and was treated with levofloxacin and methylprednisolone. He presented a month later and was found to have a large left-sided thick-walled fluid collection found to be an empyema. A chest tube was placed, and fluid culture grew Fusobacterium nucleatum. The patient was successfully treated with intrapleural fibrinolytic therapy and amoxicillin-clavulanic acid.