Medicine
Last updated on: January 11th, 2021
Legionnaires' Disease
Clinicals - History
Introduction
Legionnaires' disease (LD), often referred to as legionellosis, is an infection caused by Legionella spp, most commonly L. pneumophila. These are gram-negative, aerobic, facultative intracellular bacilli found as free-living forms in freshwater and soil, or as intracellular parasites within protozoa.
Symptoms of pneumonia
These include fever, nonproductive cough, headache, myalgias, rigors, dyspnea, diarrhea, and delirium. Importantly, these findings are nonspecific, being shared with patients having other types of pneumonia.
Gastrointestinal symptoms
Between one-third to one-half of patients develop prominent gastrointestinal symptoms, including nausea, vomiting, and diarrhea.
Environmental exposure
Legionella infection commonly occurs through exposure to contaminated water or soil following aerosolization of water particles containing the bacterium.
Patients may have a history of exposure to water, such as may occur in periods of increased rainfall; or may work in a garden, for example. Alternately, the source may be a contaminated water supply or cooling system; these can be located in hotels, cruise ships, etc., leading to outbreaks of the disease.
Risk factors
Patients who smoke, suffer from lung disease, are diabetic or have other immunocompromising conditions are at increased risk. Studies also show that males over 55 have a higher chance of developing LD.
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