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Query: UMLS:C0023241 (Legionella)
 6,990 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ten recorded epidemics of Legionnaires' disease are reviewed to gain a working perspective on the epidemiology of the disease. Salient features have included a summer-fall seasonality, a male predominance that may largely reflect increased exposure risk among men, and a striking absence of person-to-person spread. That the disease is spread primarily via the airborne route is well established; air-treatment and air-conditioning equipment has been implicated as the amplification and delivery system in four epidemics. Soils and excavation sites have been suggested as sources of the organism in at least one recorded epidemic. Evidence to date suggests that the Legionnaires' disease bacterium may be widespread in nature. More complete epidemiologic understanding must await development of improved microbiologic and immunologic tests.
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PMID:Epidemiology of Legionnaires' disease. 43 25

The immune response to the Legionnaires' disease (LD) bacterium has been shown serologically. Recent evidence suggests significant differences in seroreactivity depending on the source of antigen; these data now unequivocally show strain variation for the LD bacterium. Nothing is known about the cellular immune reactivity in patients with Legionnaires' disease. There is little evidence that the lesions and manifestations of the disease are due to immunopathologic mechanisms. Possible explanations for the pathogenesis of pulmonary lesions in Legionnaires' disease include toxic factors, bacterial chemotactic factors, neutral proteases (with complement cleaving activity), lipopolysaccharides, and products of lymphocytes.
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PMID:Immunology and immunopathology of Legionnaires' disease. 43 26

A review of the medical records of 123 persons with Legionnaires' disease hospitalized in the 1976 Philadelphia epidemic showed that the manifestations of infection ranged from mild grippe to a severe pneumonia that also involved other organ systems. Early in the illness, constitutional symptoms predominated. Fever, malaise, myalgia, rigors, confusion, headache, and diarrhea were usually followed by nonproductive cough and dyspnea. Physical examination showed few abnormalities other than rales. Moderate leukocytosis with left shift, elevated erythrocyte sedimentation rate, elevation of serum levels of liver enzymes, and hematuria and proteinuria were characteristic. Chest radiograph showed patchy, often nodular, areas of consolidation. Progression of pneumonia led to respiratory failure and the need for mechanical ventilatory assistance for 19 patients; renal failure, primarily after shock, occurred in 18 persons. Twenty-six patients died. Treatment with erythromycin or tetracycline resulted in the lowest case-fatality ratios, but the associations were not statistically significant.
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PMID:Legionnaires' disease: clinical features of the epidemic in Philadelphia. 43 27

An analysis of seven sporadic cases of Legionnaires' disease confirmed clinical features recorded during epidemics and identified aspects of the illness either unreported or not emphasized. Four patients had central nervous system abnormalities. Mental status changes included somnolence, obtundation, delirium, disorientation, and confusion. Three patients experienced visual hallucinations, and one patient without pneumonia had a grand mal seizure with residual memory deficit. Two patients had disseminated intravascular coagulation with thrombocytopenia, elevated split fibrin products, and prolonged partial thromboplastin and prothrombin times. Four patients had severe hypoxia; one patient had an exudative pleuritis. One patient whose treatment included erythromycin had radiologic improvement of his pneumonia despite deteriorating ventilatory function that led to death. The concept of Legionnaires' disease as a severe, diagnostically perplexing pneumonic illness is valid but too narrow. The emerging spectrum is that of a multisystem disease that, besides the lungs, often involves the central nervous system and can be accompanied by disseminated intravascular coagulation.
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PMID:Sporadic cases of Legionnaires' disease: the expanding clinical spectrum. 43 28

Early diagnosis of Legionnaires' disease is difficult because other pathogens cause a similar clinical picture and microbiologic tests are usually only of retrospective value. Since May 1977, 17 patients with sporadic cases of Legionnaires' disease have been admitted, all previously well, the diagnosis being made with standard serologic or bacteriologic criteria. From the clinical, laboratory, and radiologic findings, we propose criteria that may enable the clinician to make a diagnosis earlier in many cases, differentiating them from other pneumonias. Within 24 hours of admission, any three of the following four features are strongly suggestive of Legionnaires' disease: [1] prodromal "viral" illness, [2] dry cough or confusion or diarrhoea, [3] lymphopenia without marked neutrophilia, [4] hyponatremia. Two thirds of cases had at least three of these features, and no false-positive diagnoses would have been made in other pneumonias that were serologically negative for Legionnaires' disease if these proposed criteria had been applied diagnostically. In the next few days the diagnosis is very likely if microbiologic tests are negative and if there is radiologic extension, abnormal liver function test results, or hypoalbuminemia.
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PMID:Early clinical differentiation between Legionnaires' disease and other sporadic pneumonias. 43 29

Sera of 24 patients with an unexplained pneumonia were tested for the presence of antibodies against the Legionnaires' disease bacterium. Fifteen patients had positive serology. The series comprised 12 male and three female patients ranging in age from 17 to 66 years (mean, 51.1 years). All of the patients had a high fever, little or no sputum production, and radiographic evidence of pneumonia. The radiographic abnormalities ranged from a patchy infiltrate to extensive consolidation. In eight patients with confirmed Legionnaires' disease, severe confusion was one of the most striking signs. A variety of antibiotics had no clear effect on the duration of the illness in these cases, although the severity seemed to be influenced. Two of the patients died, and in three the course was protracted. All cases were sporadic. Eight patients had been infected abroad and seven in the Netherlands, two of whom were on immunosuppressive therapy and were infected in a hospital.
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PMID:Sporadic cases of Legionnaires' disease in the Netherlands. 43 30

Retrospectively, we clinically compared community-acquired cases of Legionnaires' disease, pneumococcal, and mycoplasmal pneumonias. Relative to pneumococcal and mycoplasmal pneumonias, patients with Legionnaires' disease were significantly more likely to present with unexplained encephalopathy, hematuria, and elevation of serum glutamic-oxalacetic transaminase than were those with pneumococcal and mycoplasmal pneumonias. We found upper respiratory symptoms infrequently in patients with Legionnaires' disease, and progression of pulmonary infiltrates occurred commonly. Differentiation of Legionnaires' disease pneumonia without encephalopathy from pneumococcal and mycoplasmal pneumonias may be difficult because of demographic, clinical, laboratory, and radiographic similarities.
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PMID:Comparative features of pneumococcal, mycoplasmal, and Legionnaires' disease pneumonias. 43 31

We used the whole lung section technique to review the macroscopic pathology in 12 patients who died with Legionnaires' disease. None of these patients had been treated with erythromycin. Consolidation was evenly distributed throughout all lobes without a consistent segmental distribution. The smallest lesions were around bronchioles or bounded by lobular septa. In most cases there was confluent involvement of multiple lobules. Extensive consolidation made distinction between a lobar and confluent lobular distribution difficult. Abscesses were present in two cases and nodular infiltrates in two others. In five additional patients, Legionnaires' disease had been treated with erythromycin. Four had a clinical response to treatment, and the fifth had diffuse staphylococcal pneumonia as the predominant lesion. Because the lungs of all five patients contained bacteria other than the Legionnaires' disease bacterium at the time of autopsy, it was difficult to ascertain the role of Legionnaires' disease bacterium in the pathology.
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PMID:Macroscopic pathology of the lungs in Legionnaires' disease. 43 32

Patients with acute Legionnaires' disease (LD) pneumonia may have persistent chronic pulmonary changes, as shown by the histologic appearance of specimens of lung from patients who had survived and autopsy specimens from patients who died after a protracted clinical course. Acute pneumonia was not seen in these lungs, and LD organisms could not be identified by the direct fluorescent antibody technique or the Dieterle silver impregnation strain; instead, there was organizing pneumonia with various degrees of interstitial inflammation and fibrosis. The LD pneumonia may fail to resolve, and the lung parenchyma in areas of previous acute inflammation is not restored to normal in some patients.
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PMID:Pulmonary sequelae of acute Legionnaires' disease pneumonia. 43 33

Open lung biopsies from three patients with Legionnaires' disease were examined by light and transmission electron microscopy. The patients had serious underlying disease. All developed a rapidly progressive pneumonia unresponsive to penicillin, oxacillin, and gentamicin. One patient, who received erythromycin, survived. Light microscopy in all three showed severe acute bronchopneumonia. The Legionnaires' disease bacterium was seen in tissue sections and confirmed by direct immunofluorescence. Transmission electron microscopy showed numerous rod-shaped intracellular organisms that were morphologically similar to other gram-negative bacteria and the Rickettsieae. They were within phagolysosomes, free in the cytoplasm, and rarely within structures resembling dilated rough endoplasmic reticulum. Lung tissue changes included marked detachment and necrosis of alveolar pneumocytes, septal and alveolar exudate with lysis, and prominent endothelial cell swelling and degeneration. Capillary and epithelial basement membranes were consistently intact, suggesting that the tissue changes are potentially capable of reverting to normal structure and function.
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PMID:Ultrastructure of lung in Legionnaires' disease. Observations of three biopsies done during the Vermont epidemic. 43 34


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