Discrimination between Legionnaires' Disease and Pneumococcal Pneumonia Based on the Clinical and Laboratory Features: A Quantitative Approach Using the Modified Winthrop-University Hospital Weighted Point System

• Published in: Internal Medicine Vol. 56; no. 5; pp. 487 - 491
• Main Authors: Hamada, Yohei, Urakami, Tosiharu, Aoki, Yosuke, Yamakuchi, Hiroki
• Format: Journal Article
• Language: English
• Published: Japan The Japanese Society of Internal Medicine 01.01.2017; Japan Science and Technology Agency
• Subjects: Adult; Aged; Community-Acquired Infections - diagnosis; Diagnosis, Differential; Female; Hospitalization; Hospitals, University; Humans; Internal medicine; Legionella; Legionnaires' disease; Legionnaires' Disease - complications; Legionnaires' Disease - diagnosis; Male; Middle Aged; Original; Patients; pneumococcal pneumonia; Pneumonia; Pneumonia, Pneumococcal - complications; Pneumonia, Pneumococcal - diagnosis; Retrospective Studies; Sensitivity and Specificity; Streptococcus pneumoniae; WUH system
• ISSN: 0918-2918; 1349-7235; 1349-7235
• DOI: 10.2169/internalmedicine.56.7399

Objective Legionnaires' disease (LD) is a common form of lobar pneumonia, but the optimum diagnostic modality has long been a subject of debate due to incomplete sensitivity and specificity. A delay in the initiation of specific therapy for LD is associated with increased mortality. The decision to treat a patient for Legionella must be made quickly. The purpose of this study was to evaluate the ability of the modified Winthrop-University Hospital WUH system to identify LD while discriminating against pneumococcal pneumonia at the time of hospitalization for community-acquired pneumonia. Methods Five patients with LD and 13 patients with pneumococcal pneumonia were retrospectively analyzed. Results The WUH system identified 4 of 5 patients with LD (sensitivity, 80%) while excluding legionellosis in 12 of 13 patients with pneumococcal pneumonia (specificity, 92%). The positive and negative likelihood ratios were 10.4 and 0.2. The area under the receiver operating characteristic curve was 0.969. Conclusion The WUH system is useful for obtaining a rapid presumptive clinical diagnosis of LD. Further investigation with a larger number of patients is strongly recommended.