Portugal s Legionella outbreak - What can we learn with it?

Transcription

1 Portugal s Legionella outbreak - What can we learn with it? Poster No.: C-1740 Congress: ECR 2015 Type: Educational Exhibit Authors: W. Schmitt, J. Abrantes, A. S. C. C. Germano, I. Cerejo, J Neves ; Lisbon/PT, Oeiras/PT, Vila Franca de Xira/PT Keywords: Occupational / Environmental hazards, Infection, Diagnostic procedure, Comparative studies, Conventional radiography, Thorax, Lung, Emergency DOI: /ecr2015/C-1740 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 28

2 Learning objectives - Identify the different risk factors, presenting symptoms and imaging pattern and compare it to the previously described. - Review the main radiologic findings at chest radiographs (CR) and correlate it to the patient's outcome. Page 2 of 28

3 Background In early November 2014, a large outbreak of Legionnaires' disease occurred, involving a total of 336 patients, causing 11 deaths. The authorities have traced the source of the Legionella bacteria back to industrial cooling towers at the Vila Franca de Xira area just northeast of Lisbon. The World Health Organization declared the outbreak a major public health emergency. In 2011 the standardized notification rate of Legionnaires' disease was 9,2 per million people within Europe. The world's largest outbreak of the disease occurred in Murcia, Spain, in July 2001, with more than 449 confirmed cases, with a case-fatality rate of 1%. The Portuguese outbreak in Vila Franca de Xira was considered the second largest outbreak so far. The first outbreak described in the literature was on 1976, when the American Legion opened its annual three-day convention in Philadelphia, Pennsylvania. Within a week, more than 130 people, mostly men, had been hospitalized, and 25 had died. They all had complained of tiredness, chest pain, and fever. Legionnaire's disease (LD) is an atypical pneumonia caused by gram-negative bacilli of the genus Legionella, the most common of which is Legionella pneumophila (Lp). Legionellosis is the term that encompasses all diseases caused by, or presumed to be caused by, the Legionella bacteria, including Legionnaires' disease, focal nonpulmonary infections, and Pontiac fever. Legionella bacteria are found in our natural aqueous environment, in lakes, streams, and even coastal oceans, at temperatures ranging from 5 C to greater than 50 C. Warm water (25 C to 40 C) supports the highest concentration of these bacteria, with warm water being the major bacterial reservoir leading to Legionnaires' disease. Transmission of Legionnaires' disease is usually by inhalation of aerosols or aspiration of water containing Legionella spp. At the present time, much of our understanding about Legionella infection has been obtained during outbreak investigations. The substantial morbidity associated with Legionnaires' disease, its widespread occurrence, and recent major outbreaks emphasize the need for further research to support early diagnosis and improve clinical or outbreak management. Page 3 of 28

4 Findings and procedure details We retrospectively analyzed the imaging findings and clinical outcomes of 190 patients, hospitalized at Vila Franca de Xira Hospital (HVFX), which had a positive urine antigen test and an imaging stored at PACS (picture archiving and communication system), during the late outbreak between 5 November and 2 December of Worldwide the age and gender distribution of cases of Legionnaires' disease are similar between countries. The disease is rare in children and most cases occur in older people and are predominantly in men ( male patients for every female patient). Of the 190 patients with confirmed disease, 117 were male (61.6%) and 73 female (38.4%). The mean age of cases was 59.9 years, ranging from 31 to 90. Fig. 1 Page 4 of 28

5 Risk factors Legionnaire's disease has been associated with certain risk factors such as: age (especially those younger than 1 y and elderly patients), smoking, and predisposing underlying conditions, such as chronic lung disease, immunodeficiency, malignancies, end-stage renal disease, and diabetes mellitus. Of the 190 patients observed, susceptibility to disease was associated with older age (36%), diabetes (24.2%) smoking (21.6%) and chronic respiratory (5.8%) or cardiovascular disease (13.7%)(Fig.2). The latter was directly related to the patients requiring care in ICU (Intensive Care Unit). Fig. 2 Page 5 of 28

6 Clinical features Legionnaires' clinical features include high fever, gastrointestinal symptoms and accompanying pneumonia. Nevertheless, pneumonia is the predominant clinical manifestation of Legionella infection. Respiratory symptoms usually occur after an incubation period of 2 to 10 days and are initially mild. This includes cough, chest pain and dyspnea. Gastrointestinal symptoms are often more prominent with diarrhea, nausea, vomiting, and abdominal pain. Neurologic abnormalities such as lethargy and headache are also common. Fig. 3: Fig. 3 - Distribution of presenting symptoms Page 6 of 28

7 Among the 190 observed patients, fever was by far the most frequent presenting symptom (89.4%), followed by cough (47.4%), myalgia/arthralgia (44.2%) and neurologic abnormalities (43.7%). As illustrated in Fig.3, the frequencies of presenting symptoms were very similar to the ones already described. Imaging features Chest radiograph was in most of cases the first (98.9%) and only imaging modality performed (98.4%). Posteroanterior chest radiographs were reviewed systematically and simultaneously by two observers (Radiology Registrars), aware of the serological confirmation of Legionella pneumonia, and posteriorly classified according to its radiographic pattern. In addition to posteroanterior views, in some instances lateral views were also available. Of the 188 chest radiographs stored at PACS on admission, 173 (92%) had positive findings. Previous studies have described an alveolar pattern of shadowing in initial stages, mostly with unilateral and unilobar infiltrate, with middle and lower-lobe predominance. Regarding imaging findings at presentation, they were unilateral in 74.6 % (n=129) (32.4 % (n = 56) on the right hemithorax and 43.3 % (n = 73) on the left) and bilateral in 25.4 % (n = 44). There was also middle or lower zone predominance in 67.9 % of cases (Fig.4). Page 7 of 28

8 Fig. 4: Fig.4 - Distribution of the positive imaging findings compared with other studies. Within the patients with positive findings at presentation, patchy infiltrates (24.8%; n=43) and lobar consolidation (54.3%; n=94) were most commonly observed. Remaining findings consisted of multifocal (14.9%; n=28) or interstitial (17.5%; n=33) infiltrates and hemithorax white-out (2.3%; n=4). Features as presence of pleural fluid was noted in 69 patients (36%), the majority of small volume with only subtle blunting of the costophrenic angle. Pleural effusion was bilateral on 22 patients (31.9%) and unilateral on 47(68.1%) (25 on the left and 22 on the right) (Fig. 5). Page 8 of 28

9 Fig. 5: Fig. 5 - Comparison of radiographic findings Page 9 of 28

10 Fig. 6 Page 10 of 28

11 Fig. 7 Page 11 of 28

12 Fig. 8 Page 12 of 28

13 Fig. 9 Page 13 of 28

14 Fig. 10 Page 14 of 28

15 Fig. 11 Page 15 of 28

16 Fig. 12 Due to an exceeding number of admissions during the outbreak, Vila Franca de Xira Hospital's emergency department went beyond its total capacity, resulting in a total of 112 patient transfers. Among the remaining hospitalized patients, 72 had a follow-up chest x-ray performed at the second or third day of hospitalization. From this, 24 (33.3%) had minimal or no change and 36 (50%) have demonstrated signs of progression. Previous studies have reported a rapid progression of the radiographic findings with bilateral infiltrates and patchy consolidative changes that progress and become confluent. A total of 13 patients have progressed from no positive findings to patchy (n=3), confluent (n=1), interstitial (n=6) and multifocal (n=3) infiltrates. Eight patients have progressed from patchy infiltrate to lobar consolidation (n=7) and multifocal infiltrate (n=1). Sixteen patients have demonstrated progression from lobar consolidation to hemithorax whiteout (n=13) and multifocal infiltrates (n=3). Multifocal infiltrate progressed in five patients Page 16 of 28

17 evolved to hemithorax white-out. Four patients who had initial chest radiographs with interstitial infiltrate showed worsening with lobar consolidation (n=3) and hemithorax white-out. Fig. 13 Among the 36 patients with worsening of imaging features, 21 (58.6%) required care in intensive care unit against 15 (41.6%) patients who did not. Of the 21 patients requiring care in ICU, radiographic findings were bilateral in 15 (71.4%) and unilateral in 6 (28.6%), being progression to hemithorax white-out the most common pattern observed (85.7%; n=18), followed by inferior lobar consolidation (9.5%; n=2) and interstitial infiltrate (4.8%; n=1)(fig.14). Page 17 of 28

18 Fig. 14 Page 18 of 28

19 Fig. 15 Six hospitalized patients have died, all requiring ICU care. From these, 3 (50%) had unilateral involvement by the time of presentation. Four had confluent infiltrates by the time of presentation, one had multifocal infiltrate and the other had hemithorax white-out. Posteriorly, two more patients had worsening of imaging features with progression to hemithorax white-out. Discussion During the late outbreak at Vila Franca de Xira, we have verified that imaging findings distribution was similar to the one previously described by Kirby BD et al, Dietrich PA et al, being unilateral (74.6%) and with middle and lower lung predominance (67.9%). Page 19 of 28

20 The most common radiographic finding at presentation was a confluent infiltrate involving a single lobe (54.3%), followed by unilobar patchy infiltrate (24.8%). These results differ from the ones described by Tan MJ et al, Dietrich PA et al and Kroboth FJ et al, where a patchy alveolar infiltrate was the most common imaging finding verified. Nevertheless, at hospitalization peak, confluent consolidation was the predominant finding at these studies. One of the main characteristics of Legionella pneumonia is a rapid progression of the radiographic findings. A faster progression or a delay in seeking for medical care may explain this results discrepancy. Additionally we have verified that from the patients requiring ICU care, a diffuse consolidation with hemithorax white-out was the most common finding observed. Among the six deaths observed, a confluent infiltrate was present in two thirds of the patients with posterior progression to a hemithorax white-out in 50% of cases. Page 20 of 28

21 Images for this section: Fig. 8 Department of Radiology: Hospital Vila Franca de Xira; Hospital Prof. Doutor Fernando da Fonseca E.P.E / Portugal 2014 Page 21 of 28

22 Fig. 10 Department of Radiology: Hospital Vila Franca de Xira; Hospital Prof. Doutor Fernando da Fonseca E.P.E / Portugal 2014 Page 22 of 28

23 Fig. 13 Department of Radiology: Hospital Vila Franca de Xira; Hospital Prof. Doutor Fernando da Fonseca E.P.E / Portugal 2014 Page 23 of 28

24 Fig. 14 Department of Radiology: Hospital Vila Franca de Xira; Hospital Prof. Doutor Fernando da Fonseca E.P.E / Portugal 2014 Page 24 of 28

25 Fig. 15 Department of Radiology: Hospital Vila Franca de Xira; Hospital Prof. Doutor Fernando da Fonseca E.P.E / Portugal 2014 Page 25 of 28

26 Conclusion During a large outbreak, it is vital to stablish a risk-stratification method. Knowing the most common imaging findings and their relation to the patients' outcome may minimize the related morbidity and mortality. Hemithorax white-out was the most frequent finding among the patients with poorer prognosis, suggesting a possible causal relationship requiring further investigation. Page 26 of 28

27 Personal information Willian Schmitt Resident, Radiology Department, Hospital Professor Doutor Fernando Fonseca, EPE João Abrantes Resident, Radiology Department, Centro Hospitalar Barreiro Montijo Ana Germano Consultant, Radiology Department, Hospital Professor Doutor Fernando Fonseca, EPE Isabel Cerejo Consultant, Radiology Department, Hospital Vila Franca de Xira Jose Neves Consultant, Radiology Department, Hospital Vila Franca de Xira Page 27 of 28

28 References 1. Kroboth FJ, Yu VL, et al. Clinicoradiographic correlation with the extent of Legionnaire disease. AJR Am J Roentgenol ; ; 2. Kirby BD, Peck H, et al. Radiographic features of Legionnaires' disease. Chest.1979;76: ; 3. Storch GA, Sagel S, et al. The chest roentgenogram in sporadic cases of Legionnaires' disease. JAMA I 981;245: ; 4. Dietrich PA, Johnson AD, et al. The chest radiograph in Legionnaires' disease. Radiology.1978; 127: ; 5. Tan MJ, Tan JS, et al. The Radiologic Manifestations of Legionnaire's Disease. Chest. 2000;117: ; 6. Rathore MH, Steele RW, et al. Legionella Infection In: UpToDate, Post TW (Ed), UpToDate, Waltham, MA, 2014; 7. "Legionnaires' Disease - Portugal." WHO. Web. Nov.-Dec Retrieved from: Bope, Edward T. Conn's Current Therapy The respiratory system: ; 9. Nick P, et al. Epidemiology and clinical management of Legionnaires' disease, Z, Volume 14, Issue 10, Pages , 2014 Elsevier; 10. Fraser DW, Tsai TR, et al. Legionnaires' disease: description of an epidemic of pneumonia. N Engl J Med 1977; 297: ; 11. Nguyen TM, Ilef D, et al. A community-wide outbreak of legionnaire's disease linked to industrial cooling towers--how far can contaminated aerosols spread? J Infect Dis. 2006; 193:102-11; 12. Garcia-Fulgueiras A, Navarro C, Fenoll D, et al. Legionnaires' disease outbreak in Murcia, Spain. Emerg Infect Dis 2003; 9:915-21; 13. Fields BS, Benson RF, Besser RE. Legionella and Legionnaires' disease: 25 years of investigation. Clin Microbiol Rev 2002; 15:506-26; Page 28 of 28