Chapter 23 : Clinical Presentation, Laboratory Diagnosis, and Treatment of Legionnaires’ Disease

Abstract:

The main diagnostic methods for Legionnaires’ disease (LD) are culture, urinary antigen detection, serology, and PCR, all of which are costly to perform and variably subject to false-positive results in low-prevalence populations. There was little support for no testing, even when empiric therapy for LD is given, as testing was regarded as important for epidemiologic and clinical reasons. There is now a considerable amount of data on nucleic acid amplification tests (NAATs), particularly PCR, for diagnosing LD. The need for rigorous assessment of nonrespiratory sample types was emphasized. The choice of empiric antibiotic therapy for CAP depends on several important considerations. Various ancillary treatments have been proposed for LD, including corticosteroids, oxygen, cytokine inhibitors, activated protein C, and glucose control. For some of these treatments there is evidence indicating benefits for treating severe infection/sepsis, although data are lacking for the specific treatment of LD. Corticosteroid therapy may be indicated for adult respiratory distress syndrome caused by LD or bronchiolitis obliterans organizing pneumonia, but this has not been systematically studied. Many who participated in a panel discussion on clinical aspects of LD, agreed that ancillary therapies shown to be beneficial for other types of pneumonia would likely be applicable to the treatment of LD.