Clinical features of patients with Legionnaires disease showing initial clinical improvement but radiological deterioration: A retrospective single-center analysis.

ABSTRACT: Patients with Legionnaires disease occasionally experience initial clinical improvement but radiological progression. However, data on this issue are so far limited. The aim of this study was to investigate changes in chest radiograph findings in patients with Legionnaires disease who showed initial clinical improvement and to identify risk factors and outcomes in these patients.All patients diagnosed with Legionnaires disease at a tertiary hospital in South Korea between March 2011 and May 2020 were retrospectively enrolled. Legionnaires disease was defined as abnormal chest radiographs accompanied by a positive finding on at least one of the following tests: urinary antigen test, sputum Legionella polymerase chain reaction, and sputum Legionella culture. Clinical improvement was defined as defervescence and decreased C-reactive protein level. Clinical and radiological records were reviewed on treatment days 7 and 14 and at discharge. We describe the characteristics of patients with clinical improvement but radiological deterioration on treatment for Legionnaires disease and compared them with patients with initial clinical improvement and stable or resolving chest radiograph findings.Of 140 patients with Legionnaires disease, 33 (24%) showed initial clinical deterioration, while the remaining 107 (76%) showed initial clinical improvement on day 7. The latter 107 patients were analyzed in this study; 22 (21%) showed radiological progression despite the clinical improvement. Risk factors for these patients were a high pneumonia severity index score and the use of mechanical ventilation. Mortality did not significantly differ between those with initial clinical improvement but radiological deterioration and those with both initial clinical and radiological improvement (28% vs 12%, P = .49).About one-fifth of patients with Legionnaires disease, especially those who had a high pneumonia severity index score and underwent mechanical ventilation, showed radiological deterioration despite of clinical improvement 1 week after appropriate treatment, while outcomes were not significantly worse in these patients. Therefore, our findings support that close monitoring without modification of antibiotics use is warranted in those who have clinical improvement regardless of radiologic findings.

Clinical and computed tomographic features of Legionella pneumonia with negative urine antigen test results.

BACKGROUND: Legionella spp. can cause severe pneumonia and most Legionella pneumonia (LP) cases are diagnosed using the urine antigen test (UAT). However, diagnosis of LP with negative UAT results (LPNUAT) is challenging. We investigated the clinical and radiological features of LPNUAT. METHODS: We retrospectively collected LP cases with positive UAT (LPPUAT) and cases of suspected LP with negative UAT that were examined by Legionella culture between July 2014 and March 2020. We investigated the clinical and CT findings for LP that showed negative UAT results and was diagnosed by culture and compared these findings with those for other pneumonias suspicious for LP with negative results in UAT and Legionella culture (OPSLP). RESULTS: Eight LPNUAT, 20 LPPUAT, and 19 OPSLP cases were included in this study. There were no significant differences in the clinical and CT findings between LPPUAT and LPNUAT when examined by UAT. In LPNUAT, dyspnea, renal dysfunction, liver dysfunction, and bilateral lesions were more commonly observed and inflammatory changes and the number of affected lobes were significantly higher when examined by culture than when examined by UAT. Comparison to OPSLP, LPNUAT did not show such differences, but rather showed disturbances in consciousness, hyponatremia and rhabdomyolysis. Furthermore, lobar consolidation was observed more frequently and bronchial wall thickening and centrilobular nodules were observed less frequently in LPNUAT. CONCLUSIONS: LP characteristics such as disturbance of consciousness, hyponatremia, rhabdomyolysis, lobar consolidation, and less bronchial wall thickening and centrilobular nodule contribute to the diagnosis of LP in patients with negative UAT results.

Legionella pneumophila Pneumonia in Pregnancy: A Case Report and Review of the Literature.

L. pneumophila is an unusual cause of pneumonia with a prevalence of 2.7%, and it is even more uncommon in pregnancy. To date, only 11 cases of Legionnaire's Disease in pregnancy have been reported, though this small number could possibly be attributed to underdiagnoses and under documentation. Case Presentation: In this paper, we present a 31-year-old Hispanic female, gravida 4, para 1 from the southwest United States who presented with a 3-week history of fever, worsening cough, dyspnea on exertion, and hypoxemia. Chest x-ray showed bibasilar infiltrates, with positive serology for Legionella IgM and IgG (1:250 and 1:640 respectively), as well as positive urinary antigen. Despite appropriate treatment with azithromycin 500 mg, she continued to have dyspnea and mild respiratory distress. Conclusion: Upon follow up, mother and fetus initially remained stable without any signs of sequelae from Legionnaire's disease, but the patient miscarried 5 weeks after the second admission to the hospital. The chest x-ray eventually cleared up after almost 21 days of azithromycin.

Study of the radiologic features of Legionnaires' disease with mediastinal adenopathy: Legionella or lymphoma?

An index case of Legionnaires's disease with mediastinal adenopathy prompted us to review our recent experience with Legionnaires' disease to determine the incidence of mediastinal adenopathy of this finding in Legionnaires' disease. We reviewed the radiographic findings of 90 hospitalized adults with Legionnaires' disease from 2015 to 2017. Excluded were 11 patients with mediastinal adenopathy due to non-Legionnaires' disease causes, e.g., lymphoma. Thirty-seven of the remaining patients had both chest films and chest computed tomography (CT) scans. Of the 37 Legionnaires' disease cases, 13/37 (35%) had mediastinal adenopathy and 8/27 (24%) also had unilateral hilar adenopathy. These chest CT findings were not seen on chest films. Chest CT scans are needed to detect mediastinal adenopathy in Legionnaires' disease. Mediastinal adenopathy may be due to Legionnaires' disease or a malignancy. Some findings in Legionnaires' disease are also present in mediastinal adenopathy due to lymphomas, e.g., highly elevated erythrocyte sedimentation rate (ESR), lactate dehydrogenase (LDH), and ferritin. Hospitalized adults with Legionnaires' disease and mediastinal adenopathy should have serial chest CT scans to monitor resolution of the mediastinal adenopathy. In hospitalized adults with otherwise unexplained persistent mediastinal adenopathy, they should be considered as being due to another etiology, e.g., lymphoma, until proven otherwise.

Community Acquired Legionnaire's Disease in a Kidney Transplant Patient.

This case report details the clinical picture of a renal transplant recipient infected with community acquired Legionella pneumonia. While it is more commonly associated as a nosocomial infection due to pathogenic organisms in a hospital's water supply, this case serves as a reminder to consider the patient's impaired cellular immune function when trying to diagnose community acquired pneumonia.

A case of Legionella pneumophila evaluated with CT and ultrasound.

A 36-year-old man was admitted to the emergency department of "SS Annunziata" hospital in Chieti complaining of a sharp chest pain arisen some hours before admission. On examination, the patient looked sweaty; his vital signs showed tachycardia and augmented breath rate; sinus tachycardia and normal ventricular repolarization were observed on ECG, and no abnormalities were observed in the echoscan of the hearth. According to the clinical and electrocardiographic findings, and to previous episode of DVT in anamnesis, a thorax CT scan was performed in order to rule out pulmonary embolism. It showed an "area of parenchymal consolidation involving almost all the left lower lobe with patent bronchial structures"; given the patient's CURB 65 score, he was then admitted to the pneumology ward where empiric treatment with levofloxacin (750 mg PO once daily) was initiated. Thoracic ultrasound was performed using a multifrequency convex transducer, and the posterior left area was examined through intercostal approach, placing the patient in a sitting position. A subpleural patchy hypoechoic lesion with irregular boundaries was detected; the maximum diameter was 11 cm, and the multiple hyperechoic spots inside it (elsewhere defined as "air bronchogram") showed no Doppler signal. Given the positive result of the Legionella urinary antigen test, antibiotic treatment was switched to Levofloxacin 1000 mg PO once daily and Claritromicin 500 mg PO twice daily. After 3 days, his clinical conditions improved dramatically. Ultrasound performed after 5 days from the diagnosis showed decreased dimensions of the lesion previously identified (maximum diameter 8.25 cm) and a marked reduction of the hyperechoic spots in it. The patient was discharged in good clinical conditions, and both thorax CT scan obtained after 1 and 4 months from the diagnosis showed radiological resolution of the parenchymal consolidation. The key to ultrasound visualization of pneumonia is its contact with the pleural surface (86-98% in cases of CAP) and the relative loss of aeration of the portion involved by the infection and a concomitant increase in the fluid content. A paradigmatic US image for parenchymal inflammatory infiltrate has not been established yet; anyway, some typical findings, when combined with the clinical features, can confirm the diagnostic hypothesis.

Early Radiographic and Tomographic Manifestations of Legionnaires' Disease.

PURPOSE: Legionnaires' disease (LD) may occur sporadically or in the course of outbreaks, where the typical radiological manifestations of the disease may better be delineated. We took advantage of a rare community-based epidemic of LD (181 patients) that occurred in 2012 in Quebec City, Canada, to describe the radiographic features of LD and compare the its tomographic presentation with that of community-acquired pneumonia caused by common bacteria other than Legionella pneumophila. METHODS: From the 181 individuals affected in the outbreak, we obtained the chest radiographs of 159 individuals (mean 63 ± 15 years of age) for detailed analysis; 33 patients had a computed tomography (CT) scan performed during the course of their illness. In a case-control study, we compared the CT scans of patients with LD with those of patients who had received a diagnosis of community-acquired pneumonia caused by a pathogen other than Legionella and confirmed by chest CT scan. RESULTS: Overall, LD most often presented as an airspace consolidation involving 1 of the lower lobes. Pleural effusion and mediastinal adenopathies were apparent only in a minority, whereas no pneumothorax or cavitation was noted. We did not find any significant difference in chest CT scan findings in patients with LD vs those with community-acquired pneumonia from other bacterial origin. No radiological finding was clearly associated with an increased risk of intensive care unit admission or mortality. CONCLUSIONS: The early radiographic and tomographic manifestations of LD are nonspecific and similar to those found in community-acquired pneumonia from other bacterial origin.

Thoracic Imaging Features of Legionnaire's Disease.

Imaging examinations are often performed in patients with Legionnaires' disease. The literature to date has documented that the imaging findings in this disorder are relatively nonspecific, and it is therefore difficult to prospectively differentiate legionella pneumonia from other forms of pneumonia, and from other noninfectious thoracic processes. Through a review of clinical cases and the literature, our objective is for the reader to gain a better understanding of the spectrum of radiographic manifestations of Legionnaires' disease.

Legionnaire's Disease and its Mimics: A Clinical Perspective.

Whenever the cardinal manifestations of a disorder occur in similar disorders, there is potential for a disease mimic. Legionnaire's disease has protean manifestations and has the potential to mimic or be mimicked by other community acquired pneumonias (CAPs). In CAPs caused by other than Legionella species, the more characteristic features in common with legionnaire's disease the more difficult the diagnostic conundrum. In hospitalized adults with CAP, legionnaire's disease may mimic influenza or other viral pneumonias. Of the bacterial causes of CAP, psittacosis and Q fever, but not tularemia, are frequent mimics of legionnaire's disease.

Chest radiographic characteristics of community-acquired Legionella pneumonia in the elderly.

BACKGROUND: Legionella is an important community-acquired pneumonia pathogen. Although the elderly are especially susceptible to Legionella, few studies have looked at comparative radiographic features of Legionella pneumonia in this population. The aim of this study was to explore the chest radiographic characteristics of community-acquired Legionella pneumonia in the elderly. METHODS: Serial chest radiographs obtained in 34 patients hospitalized with serologically proven Legionella pneumonia were retrospectively reviewed. Chest X-ray features of an aged group of ≥ 65 years were assessed and compared with a non-aged group of <65 years old with regard to initial patterns and distributions of pulmonary abnormalities, accompanying signs, and progression. RESULTS: The most common initial presentation was a patchy alveolar infiltrate involving a single lobe, most often the lower lobe. There was no middle or lingular lobe involvement in the aged group patients, but bilateral pleural effusion was significantly more common in this group. In the aged group patients, radiographic progression following adequate therapy, despite a clinical response, was more often noted and the radiographs were less likely to have returned to the premorbid state at discharge, but the differences were not significant between the two groups. CONCLUSION: The discrepancy between imaging findings and clinical symptoms seems more prominent in community-acquired Legionella pneumonia in the elderly.

Legionella pneumonia complicated by myocarditis and torsades de pointes: A case report and review of literature.

Legionella infection most commonly manifests as pneumonia. Extrapulmonarylegionellosis is rare, but the clinical manifestations are often dramatic. Myocardialinvolvementis the most common extrapulmonary manifestation of legionellosis and can result in left ventricular dysfunction. We report a case of Legionellapneumopbila-induced myocarditis and acute left ventricular dysfunction with subsequent development of torsades de pointes (TdP) in a young adult with no other risk factors. Early recognition of this complication is paramount as timely initiation of appropriate antibiotics is crucial to ensure full recovery from this form of reversible carditis.

Detection of Legionella pneumophila serogroup 1 in blood cultures from a patient treated with tumor necrosis factor-alpha inhibitor.

A 65-year-old man was admitted to our hospital with a temperature of 39.3 °C, cough, sputum, and pharyngeal discomfort that had persisted for 3 days. He had been treated with methotrexate and adalimumab (a tumor necrosis factor-alpha [TNF-α] inhibitor) for rheumatoid arthritis for 2 years, and he had also been treated with S-1 (tegafur, gimeracil, and oteracil potassium) for pancreatic metastasis of gastric cancer for 2 months. Regardless of the underlying pathologies, his general condition was good and he had worked as an electrician until 2 days before admission. However, his appetite had suddenly decreased from the day before admission, and high fever and hypoxia were also evident upon admission. A chest X-ray and computed tomography scan revealed left pleural effusion and consolidation in both lungs. The pneumonia severity index score was 165 and the risk class was V. Accordingly, we started to treat the pneumonia with a combination of levofloxacin and meropenem. Thereafter, we received positive urinary antigen test findings for Legionella pneumophila. After hospitalization, hypoxia was progressed and hypotension was emerged. Despite the application of appropriate antibiotics, vasopressors, and oxygenation, the patient died 8 h after admission. Even after his death, blood cultures were continued to consider the possibility of bacterial co-infection. Although no bacteria were detected from blood cultures, Gimenez staining revealed pink bacteria in blood culture fluids. Subsequent blood fluid culture in selective medium revealed L. pneumophila serogroup 1. Recently, TNF-α inhibitors have been described as a risk factor for Legionnaires' disease. In consideration of the increased frequency of TNF-α inhibitors, we may need to recognize anew that L. pneumophila might be a pathogen of severe community-acquired pneumonia.

Diagnosis of fulminant pneumonia caused by Legionella pneumophila serogroup 8 with the sequence analysis of the 16S rRNA gene.

Pneumonia is the fourth leading cause of death in Japan. Accurate and rapid detection of the causative pathogen(s) is necessary and important for appropriate antimicrobial treatment, especially in patients with rapidly progressive pneumonia or immunocompromised patients. Conventional methods, such as cultivations, detection of urinary antigens or PCR amplification of specific genes, inevitably require the precise presumption of potential pathogens in each case, and pneumonia caused by unanticipated microorganisms might lead to inadequate antimicrobial treatments and unfortunate consequences. We herein report an immunocompromised female patient (69 years old) with fulminant pneumonia caused by Legionella (L.) pneumophila serogroup 8. Ordinary cultivation methods and urinary antigen detection failed to identify the causative organisms. Accordingly, DNA was extracted from the bronchoalveolar lavage fluid and used for the PCR-based cloning of the bacterial 16S rRNA gene. Sequencing analysis of the isolated clones revealed the predominance of L. pneumophila. Based on this information, the patient received an appropriate and successful antimicrobial treatment. In addition, L. pneumophila serogroup 8 was identified with culturing the bronchoalveolar lavage fluid and serotyping with L. pneumophila antisera. The 16S rRNA gene sequencing analysis can reveal the potential pathogens without any presumption about the organism, and can evaluate the kinds and ratio of bacterial species in each specimen. In conclusion, this cultivation-independent method is a potential diagnostic modality for pneumonia, especially in patients with rapidly progressive pneumonia or those who are immunocompromised.

Organizing pneumonia pattern in the follow-up CT of Legionella-infected patients.

The main aim of this study was to describe the appearance of the CT pattern of organizing pneumonia in Legionella-infected patients. Serial CT scans obtained from five sporadic cases of Legionella pneumophila pneumonia were retrospectively reviewed. The mean time of follow-up was 14 days. Chest CT was analyzed with regard to frequency and appearance of CT patterns of pulmonary abnormalities. Consolidation and ground-glass opacities, with or without an air bronchogram, were the most common abnormalities detected in CT scans during follow-up patients with L. pneumophila pneumonia. Two patterns were observed: subpleural and peribronchovascular. The subpleural pattern was seen in four patients and the peribronchovascular pattern in one. Interlobular septal thickening was seen in one patient. Pleural effusion was seen in one patient. The CT pattern of organizing pneumonia, a subpleural pattern, was frequently observed after treatment of L. pneumophila pneumonia.