Severe Legionella pneumonia: Rapid presumptive clinical diagnosis with Winthrop-University Hospital's weighted point score system (modified)

Abstract

Legionnaires' disease is a systemic infection involving the lungs and accompanied by a characteristic pattern of extrapulmonary organ involvement. Legionnaires' disease is one of the non-zoonotic causes of atypical community-acquired pneumonia (CAP). Legionnaires' disease commonly presents as severe CAP requiring hospitalization and intensive care. Each atypical CAP has its own characteristic pattern of extrapulmonary laboratory clinical findings and abnormalities that are the basis of clinical syndromic diagnosis. Studies have been unsuccessful in identifying individual clinical and laboratory parameters that are specific for Legionella. Individually, clinical and laboratory abnormalities lack diagnostic specificity. The diagnostic specificity of clinical and laboratory findings is increased when combined and are the basis of a clinical syndromic diagnosis. The importance of serial nonspecific laboratory abnormalities with Legionnaires' disease is emphasized. The sensitivity and specificity of a clinical syndromic diagnosis are enhanced if they are based on a weighted point score system. A diagnostic weighted point score system is based on the varying diagnostic importance of clinical and laboratory diagnostic findings. The Winthrop-University Hospital's Infectious Disease Division's rapid clinical diagnostic weighted point system is based on a weighted point score of clinical and laboratory findings. The case presented is that of a 55-year-old man with severe CAP who required hospitalization and intensive care admission. The presumptive clinical diagnosis of Legionella CAP was based on the Winthrop-University Hospital Infectious Disease Division's weighted point score system, which permitted early empiric anti-Legionella antimicrobial therapy and prompted specific Legionella testing. Legionnaires' disease is definitively diagnosed by serology or a urinary Legionella antigen test. This case of severe Legionnaires' CAP was confirmed by urinary antigen test reported on hospital day 6. The Winthrop-University Hospital is weighted point score system (modified) permits a rapid clinical presumptive diagnosis of Legionnaires' disease and is an accurate predictor of Legionella CAP.

Severe Q fever community-acquired pneumonia (CAP) mimicking Legionnaires' disease: Clinical significance of cold agglutinins, anti-smooth muscle antibodies and thrombocytosis

“…Because of the pattern of organ involvement and lack of a positive zoonotic vector history, the working diagnosis was Legionnaires' disease. 1,15,[20][21][22][23] Arguing against the diagnosis of Legionnaires' disease was the absence of hypophosphatemia and mild hepatomegaly. 15,[20][21][22][23] During the patient's hospital course, she developed thrombocytosis.…”

C. pneumoniae community-acquired pneumonia (CAP) in mimicking Mycoplasma pneumoniae meningoencephalitis complicated by asthma

“…Against the diagnosis of Legionnaire's disease was the absence of hypophosphatemia, diarrhea, microscopic hematuria, increased serum transaminases, and a minimally non-elevated serum ferritin level. 1,8,9 The most likely alternative diagnosis was severe M. pneumoniae CAP with meningoencephalitis. Against the diagnosis was the dense nature of the focal/ segmental pulmonary infiltrate, the CAP severity, a temperature greater than 102°F, and the absence of highly elevated cold agglutinin titers.…”

“…Legionnaire's disease was ruled out with Legionella serology and urinary antigen results. 1,8,9 Although the patient responded well to quinolone therapy, he subsequently developed permanent asthma. Preexisting asthma may be exacerbated by C. pneumoniae or M. pneumoniae infection.…”

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

“…The modified Winthrop-University Hospital's weighted point system (WUH system) for the diagnosis of LD was developed by Cunha et al in 2008 (8,9) to enable physicians to tentatively diagnose this disease on the day of a patient's encounter. In the present study, patients with CAP caused either by Streptococcus pneumoniae or Legionella species were retrospectively analyzed, and the validity of the WUH system in discriminating the two diseases was investigated.…”