Legionnaires' disease. Clinical findings and one-year follow-up.

The cases of six patients with Philadelphia Legionnaires' disease were studied during the acute phase and throughout the following year. This multisystems disease process developed abruptly with symptoms of chills, fever, myalgias, and headache. The unusual clinical association of fever with relative bradycardia was noted frequently. Pneumonia developed after the first few days and rapidly progressed to life-threatening respiratory failure despite penicillin and cephalosporin therapy. Improvement occurred within 48 hours after tetracycline or chloramphenicol was administered. No permament sequelae were noted on the one-year follow-up examination, and no secondary cases of infection occurred.