Uncommon causes of atypical pneumonia: Increasing prevalence or increasing detection?

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1 Uncommon causes of atypical pneumonia: Increasing prevalence or increasing detection? Poster No.: P-0051 Congress: ESTI 2015 Type: Educational Poster Authors: K. Stefanidis, C. Sayer, D. A. Scobie, D. P. Riley, S. Grubnic, I. Vlahos; London/UK Keywords: Infection, Diagnostic procedure, CT-High Resolution, CT, Conventional radiography, Respiratory system DOI: /esti2015/P-0051 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 49

2 Learning objectives To present the radiological impact of new molecular techniques in the detection of previously uncommon organisms. To review the typical imaging findings of many of these "new" organisms. To present different imaging intepretation strategies in the recognition of different atypical pathogens. Background Despite advances in diagnosis and treatment, lower respiratory tract infection and atypical pneumonia continues to be a major cause of morbidity and mortality. In the last two decades, there has been increase not only in the prevalence of various infections but also in the recognition of several "new" viral pathogens especially due to the use of new molecular tools (polymerase chain reaction-pcr). These include human metapneumovirus, influenza A, parainfluenza, rhinovirus, enterovirus and coronavirus. Imaging findings OR Procedure details EPIDEMIOLOGY Atypical pneumonias constitutes a significant proportion of community acquired pneumonias (CAP). It has been recognized that viral respiratory pathogens represent 15-65% of CAP. However, in the last two decades there has been increase not only in the prevalence of various "atypical" organisms but also in the recognition of several "new" viral pathogens. Many of these atypical infections were likely previously present but unrecognized due to the lack of sophisticated molecular methods. However, in most of the cases, the diagnosis still relies on clinical suspicion. CLINICAL PRESENTATION Low grade fever. More pronounced constitutional symptoms, such as headache and myalgia. Persistent dry cough. More insidious onset. Page 2 of 49

3 Mixture of upper and lower lower respiratory tract symptoms and signs. PATHOLOGY The most common causes of atypical pneumonia include: Mycoplasma pneumonia Legionella pneumonia Viruses including influenza, respiratory syncytial virus (RSV), human metapneumovirus, coronavirus, rhinoviruses, enterovirus, adenovirus. Chlamydia pneumonia Coxiella burnettii (Q fever) PCP (in the setings of HIV/AIDS) DIAGNOSTIC TESTS Within the last decade, recognition of various "atypical" organisms has become more important because of the unexpected emergence of several new respiratory viruses. Due to the similarity in clinical presentation of respiratory tract infections, causative pathogens could not be identified on the basis of symptoms alone. To overcome these limitations, new molecular techniques has been introduced in the detection of previously uncommon organisms, allowing detection of the disease in the acute phase: Polymerase Chain Reaction (PCR) and multiplex PCR in the simultaneous detection of Mycoplasma pneumoniae, Legionella pneumophila, Chlamydia pneumoniae and respiratory viruses (DNA target). Reverse transriptase PCR (modification of PCR) when the initial template is RNA rathen than DNA. ROLE OF IMAGING EXAMINATIONS In lower respiratory tract infection both Chest Radiography and more specifically Computed Tomography (CT) remain essential in determining the presence and distribution of infective disease, and may guide diagnostic procedures such as bronchoscopic lavage. However, the radiologic and clinical microbiological aetiologic determination has become more challenging because of the similar and overlapping imaging manifestations of a now wider variety of identifiable organisms, many of which may co-exist. Whereas radiology may be of limited value in determining the specific etiology of pneumonia, a detailed knowledge of expected patterns may assist the clinician to determine the dominant infective organism and to exclude certain organisms as pathogenic. These findings include distribution, symmetry and the presence of effusions or adenopathy. By HRCT additional findings such as ground glass, reticulation, Page 3 of 49

4 centrilobular solid or ground glass nodules may aid distinction. In combination with clinical parameters these may narrow the aetiological profile. CLINICAL CASES/SCENARIOS OF ATYPICAL PNEUMONIA AND DIFFERENT RADIOLOGICAL PATTERNS. CASE 1: Fig. 1: CASE 1. Mycoplasma References: ST GEORGE'S HOSPITAL, LONDON, UK Page 4 of 49

5 Fig. 2: CASE 1. Mycoplasma References: ST GEORGE'S HOSPITAL, LONDON, UK MYCOPLASMA PNEUMONIA Mycoplasma are bacteria that lack a cell wall and grow in an extracellular location. The most important pathogen is Mycoplasma pneumoniae. M. pneumoniae is one of the more common causes of community-acquired pneumonia, accounting for approximately 10% to 15% of overall cases and up to 50% of cases in specific groups, such as military recruits. Infections occur throughout the year, with a peak during the autumn and early winter. Page 5 of 49

6 Fig. 3 References: ST GEORGE'S HOSPITAL, LONDON, UK CASE 2: Page 6 of 49

7 Fig. 4: CASE 2. Coronavirus References: ST GEORGE'S HOSPITAL, LONDON, UK Page 7 of 49

8 Fig. 5: CASE 2. Coronavirus References: ST GEORGE'S HOSPITAL, LONDON, UK SARS-CORONAVIRUS Coronaviruses are a large family of viruses that cause a range of illnesses in humans, from the common cold to the Severe Acute Respiratory Syndrome (SARS). Page 8 of 49

10 Fig. 7: CASE 3. Metapneumovirus References: ST GEORGE'S HOSPITAL, LONDON, UK Page 10 of 49

11 Fig. 8: CASE 3. Metapneumovirus References: ST GEORGE'S HOSPITAL, LONDON, UK METAPNEUMOVIRUS Metapneumovirus is a recently identified RNA virus, genus Metapneumovirus. It is usually associated with acute respiratory tract infections including upper airway disease, lower airway bronchitis and bronchiolitis, influenza-like syndrome, and pneumonia. In adults, epidemiologic studies have demonstrated that HMPV infection accounted for 4% of cases among patients with community-acquired pneumonia or chronic obstructive pulmonary disease exacerbations. Page 11 of 49

13 Fig. 10: CASE 4. Influenza A References: ST GEORGE'S HOSPITAL, LONDON, UK Page 13 of 49

14 Fig. 11: CASE 4. Influenza A References: ST GEORGE'S HOSPITAL, LONDON, UK INFLUENZA A Influenza virus has been recognized as important cause of hospitalization in elderly adults during the winter months. Page 14 of 49

16 Fig. 13: CASE 5. RSV References: ST GEORGE'S HOSPITAL, LONDON, UK RESPIRATORY SYNCYTIAL VIRUS Respiratory Syncytial Virus (RSV) is a common cause of upper and lower respiratory tract infection in infants and small children. Infection in adults is usually mild and limited to the upper respiratory tract. However, pneumonia can occur, particularly, in the elderly or chronically ill patients in nursing homes or hospital and in immunocompromised individuals. Page 16 of 49

18 Fig. 15: CASE 6. Rhinovirus References: ST GEORGE'S HOSPITAL, LONDON, UK RHINOVIRUS Rhinoviruses cause the majority of common cold syndromes. With the exception of severely immunocompromised hosts, these viruses are uncommonly associated with severe illnesses resulting in hospitalizations. This phenomenon may be due to the limited virulence of these pathogens and the pathogenesis of their infections, but it may also be due to the lack of detection, either because of the failure to perform appropriate tests or the difficulty in identifying these organisms using standard viral culture and serologic techniques. Rhinoviruses has also been implicated in exacerbations of chronic obstructive pulmonary disease (COPD). However, the role of Rhinovirus in the pathogenesis of pneumonia remains controversial. Page 18 of 49

20 Fig. 17: CASE 7. Legionella References: ST GEORGE'S HOSPITAL, LONDON, UK Page 20 of 49

21 Fig. 18: CASE 7. Legionella References: ST GEORGE'S HOSPITAL, LONDON, UK LEGIONELLA Legionella pneumophila pneumonia is a fatal pneumonia, and therefore, early diagnosis and treatment is crucial. This illness presents in outbreaks or sporadically. Legionella is responsible for 1% to 5% of community-acquired pneumonias requiring hospitalization. Page 21 of 49

23 Fig. 20: CASE 8. PCP References: ST GEORGE'S HOSPITAL, LONDON, UK PNEUMOCYSTIS PNEUMONIA Pneumocystis jiroveci is a common cause of life-threatening opportunistic infection in patients with AIDS. Most patients have CD4 counts of <100 cells per mm3 at the time of diagnosis of their first episode of PCP. Page 23 of 49

24 Fig. 21 References: ST GEORGE'S HOSPITAL, LONDON, UK TYPICAL BACTERIAL OR ATYPICAL PNEUMONIA Page 24 of 49

25 Fig. 22 References: ST GEORGE'S HOSPITAL, LONDON, UK Images for this section: Page 25 of 49

26 Fig. 1: CASE 1. Mycoplasma Page 26 of 49

27 Fig. 2: CASE 1. Mycoplasma Page 27 of 49

28 Fig. 4: CASE 2. Coronavirus Page 28 of 49

29 Fig. 5: CASE 2. Coronavirus Page 29 of 49

30 Fig. 6 Page 30 of 49

31 Fig. 7: CASE 3. Metapneumovirus Page 31 of 49

32 Fig. 8: CASE 3. Metapneumovirus Page 32 of 49

33 Fig. 9 Page 33 of 49

34 Fig. 10: CASE 4. Influenza A Page 34 of 49

35 Fig. 11: CASE 4. Influenza A Page 35 of 49

36 Fig. 12 Page 36 of 49

37 Fig. 13: CASE 5. RSV Page 37 of 49

38 Fig. 14 Page 38 of 49

39 Fig. 15: CASE 6. Rhinovirus Page 39 of 49

40 Fig. 16 Page 40 of 49

41 Fig. 17: CASE 7. Legionella Page 41 of 49

42 Fig. 18: CASE 7. Legionella Page 42 of 49

43 Fig. 19 Page 43 of 49

44 Fig. 20: CASE 8. PCP Page 44 of 49

45 Fig. 21 Page 45 of 49

46 Fig. 3 Page 46 of 49

47 Fig. 22 Page 47 of 49

48 Conclusion Recognition of typical imaging patterns of disease caused by organisms that previously may have been occult pathogens of atypical pneumonia may assist clinical management of patients with unusual microbiological findings or polymicrobial disease. References Jennings LC, Anderson TP, Werno AM, et al. Viral etiology of acuterespiratory tract infections in children presenting to hospital: role of polymerase chain reaction and demonstration of multiple infections. Pediatr Infect Dis J 2004;23: Reittner P, Müller NL, Heyneman L, Johkoh T, Park JS, Lee KS, Honda O, Tomiyama N. Mycoplasma pneumoniae pneumonia: radiographic and high-resolution CT features in 28 patients. AJR Am J Roentgenol 2000; 174: Okada F, Ando Y, Wakisaka M, Matsumoto S, Mori H. Chlamydia pneumoniae pneumonia and Mycoplasma pneumoniae pneumonia: comparison of clinical findings and CT findings. J Comput Assist Tomogr 2005; 29: Creer DD, Dilworth JP, Gillespie SH, et al. Aetiological role of viral and bacterial infections in acute adult lower respiratory tract infection (LRTI) in primary care. Thorax 2006;61:75-9. Sakai F, Tokuda H, Goto H, Tateda K, Johkoh T, Nakamura H, Matsuoka T, Fujita A, Nakamori Y, Aoki S, Ohdama S. Computed tomographic features of Legionella pneumophila pneumonia in 38 cases. J Comput Assist Tomogr 2007; 31: Franquet T, Rodríguez S, Martino R, Salinas T, Giménez A, Hidalgo A. Human metapneumovirus infection in hematopoietic stem cell transplant recipients: high-resolution computed tomography findings. Journal of Computer Assisted Tomography 2005;29(2): Feurestein IM, Archer A, Pluda JM, Francis PS, Falloon J, Masur H, Pass HI, Travis WD. Thin-walled cavities, cysts, and pneumothorax in Pneumocystis carinii pneumonia: fur- ther observations with histopathologic correlation. Radiology 1990; 174: Kuhlman JE, Kavuru M, Fishman EK, Siegelman SS. Pneumocystis carinii pneumonia: spectrum of parenchymal CT findings. Radiology 1990; 175: Personal Information Page 48 of 49

49 Dr. Konstantinos Stefanidis St George's Hospital, London, UK. Page 49 of 49