Sporadic cases of Legionnaires' disease: the expanding clinical spectrum.

An analysis of seven sporadic cases of Legionnaires' disease confirmed clinical features recorded during epidemics and identified aspects of the illness either unreported or not emphasized. Four patients had central nervous system abnormalities. Mental status changes included somnolence, obtundation, delirium, disorientation, and confusion. Three patients experienced visual hallucinations, and one patient without pneumonia had a grand mal seizure with residual memory deficit. Two patients had disseminated intravascular coagulation with thrombocytopenia, elevated split fibrin products, and prolonged partial thromboplastin and prothrombin times. Four patients had severe hypoxia; one patient had an exudative pleuritis. One patient whose treatment included erythromycin had radiologic improvement of his pneumonia despite deteriorating ventilatory function that led to death. The concept of Legionnaires' disease as a severe, diagnostically perplexing pneumonic illness is valid but too narrow. The emerging spectrum is that of a multisystem disease that, besides the lungs, often involves the central nervous system and can be accompanied by disseminated intravascular coagulation.