Concurrent legionnaires' disease and active pulmonary tuberculosis.

A 68-yr-old man was admitted to the hospital with severe Legionnaires' disease, which was serologically confirmed by a 6-fold increase in antibody titers to Legionella pneumophila, serogroup 1. The patient improved dramatically with intravenously administered erythromycin therapy but was discharged from the hospital with residual debility and pulmonary complaints later recognized as being caused by active pulmonary tuberculosis. The diagnostic and therapeutic confusion engendered by the concurrence of these pulmonary infections is discussed.