The spectrum of legionnaires' disease: a case series illustrating clinical diversity and outcomes.

BACKGROUND

Legionella pneumophila causes Legionnaires' disease, a severe atypical pneumonia with variable clinical presentation and significant morbidity and mortality. The Centers for Disease Control and Prevention reports that Legionnaires' disease incidence has steadily increased since the early 2000s. Despite over 40 years of recognition, clinical awareness remains suboptimal.

CASE DESCRIPTION: We present five patients with confirmed Legionnaires' disease in a community hospital setting. Patients' ages ranged from 38 to 83 years old with varied comorbidities. Clinical presentations included respiratory symptoms (cough, dyspnea), systemic manifestations (fever, fatigue, malaise), and extrapulmonary features (diarrhea, hyponatremia). Hyponatremia was present in 40% of the cohort. Chest imaging revealed unilateral or bilateral infiltrates. Diagnosis was confirmed via urinary antigen testing detecting Legionella pneumophila serogroup 1. Duration of hospitalization ranged from 3 to 10 days. Four patients were successfully treated with levofloxacin or azithromycin and discharged; one patient with multiple comorbidities died from septic and cardiogenic shock despite appropriate antimicrobial therapy.

CONCLUSIONS

This case series reinforces the variable clinical presentation of Legionnaires' disease and emphasizes the critical importance of clinical suspicion in patients with atypical pneumonia, particularly those with risk factors including advanced age, comorbidities, or exposure to aerosolized water sources. Early recognition and appropriate antimicrobial therapy are essential to reduce morbidity and mortality.