Atopic Pulmonary Disease: Findings on Thoracic Imaging

Transcription

1 July 2003 Atopic Pulmonary Disease: Findings on Thoracic Imaging Rebecca G. Breslow Harvard Medical School Year IV

2 Churg-Strauss Syndrome Hypersensitivity Pneumonitis Asthma Atopic Pulmonary Disease Allergic Bronchopulmonary Aspergillosis Eosinophilic Pneumonia 2

3 Normal Lung Anatomy Tracheobronchial Tree Normal lung at level inferior pulmonary veins Novelline and Squire, Living Anatomy, 1987 L inferior pulmonary vein R inferior pulmonary vein Murray & Nadel: Textbook of Respiratory Medicine, 2000 Lower lobe bronchi 3

4 Asthma

5 Asthma: Pathophysiology and Work-up Pathophysiology: airway inflammation, reversible airway obstruction, and hyperreactivity of airways to various stimuli Work-up: Pulmonary function tests documentation of physiologic airway obstruction that responds to a bronchodilator Chest radiograph Computed Tomography 5

6 Asthma Differential Diagnosis vocal chord dysfunction mechanical large airway obstruction bronchiolitis infiltrative lung disease heart failure hypersensitivity pneumonitis allergic bronchopulmonary aspergillosis 6

7 Asthma: Chest Radiographs Indications symptoms refractory to conventional treatment Findings increased interstitial markings (bronchial wall thickening) hyperinflation complications related to severe asthma (status asthmaticus) atalectasis pneumothorax pneumomediastinum 7

8 Asthma: Chest Radiographs Hyperinflation UpToDate Online 8

9 Asthma: Complications seen in Status Asthmaticus Pneumomediastinum Atalectasis UpToDate Online 9

10 Asthma: Computed Tomography Indications Findings detection of bronchiectasis in patients with suspicion of allergic bronchopulmonary aspergillosis documenting presence and extent of emphysema in smokers with asthma identifying conditions, such as hypersensitivity pneumonitis, which may be confused with asthma quantification of changes in luminal diameter of asthmatic airways to aid clinical research studies bronchial wall thickening bronchial dilatation expiratory air trapping 10

11 Asthma: CT Inspiratory Film Expiratory Film Lucent, air-filled lung fields Air-Trapping 11 Courtesy of Dr. Phillip Boiselle, BIDMC

12 Allergic Bronchopulmonary Aspergillosis (ABPA)

13 ABPA: Pathophysiology and Pathophysiology Work-Up Aspergillus fumigatus colonization of asthmatic airways prompts IgE- and IgG-mediated immune response (immediate hypersensitivity reaction) Th2-mediated eosinophilic inflammation combines with proteolytic enzymes and mycotoxins released by fungi airway damage Work-Up Prick skin test to evaluate reactivity to Aspergillus antigens Serum assay of total IgE and precipitins to Aspergillus Chest radiographs High resolution computed tomography 13

14 ABPA Differential Diagnosis: obstructive pulmonary disease infection granulomatous disease Churg-Strauss syndrome bronchiolitis obliterans organizing pneumonia chronic bronchitis cystic fibrosis bronchial adenoma bronchogenic carcinoma 14

15 ABPA: Chest Radiographs Indications: obtain during initial work-up as baseline study Findings: central bronchiectasis with increased prominence in upper lobes mucoid impaction ( toothpaste shadows or gloved- finger appearance extending from hilum) patchy parenchymal opacities (lobar, segmental or subsegmental) ) most commonly affecting the midzones atalectasis due to proximal mucoid impaction 15

16 ABPA: High Resolution Computed Tomography Indications: obtain if negative chest radiograph but prick skin test and serologic test positive (greater sensitivity for bronchiectasis) serial studies useful to determine progression of disease Findings: parenchymal infiltrates bronchiectasis mucoid impaction and atalectasis bronchial wall thickening 16

17 ABPA: HRCT Scout film CT coronal reconstruction Tubular opacities Courtesy of Dr. Phillip Boiselle, BIDMC Mucoid impaction and bronchial wall thickening 17

18 ABPA: HRCT Axial images Gloved-finger shadows (intrabronchial exudates and bronchial wall thickening) 18 Courtesy of Dr. Phillip Boiselle, BIDMC

19 Chronic Eosinophilic Pneumonia (CEP)

20 CEP: Pathophysiology and Pathophysiology: Work-Up an idiopathic disorder characterized by an abnormal accumulation of eosinophils in the lung accompanied or preceded by asthma in over 50% of cases Work-up Measurement of peripheral eosinophil counts, IgE levels and ESR Bronchoalveolar lavage (>40% eosinophilia suggestive of CEP) Chest radiographs Computed tomography 20

21 CEP Differential Diagnosis infection: tuberculosis, atypical pneumonia pulmonary fibrosis infiltrative lung disease obstructive pulmonary disease neoplasm 21

22 CEP: Chest Radiographs Indications: distinctive pattern on chest radiograph helpful for diagnosis, though present in only 33% of cases serial plain films used to monitor response to corticosteroid treatment Findings bilateral peripheral or pleural-based infiltrates ( photographic negative of pulmonary edema) CT more sensitive for detection radiographic abnormalities, but has not been shown to be superior to chest radiographs for assessment of disease activity findings may persist on CT scan several weeks to months after complete resolution on plain films 22

23 CEP: Chest Radiographs Infiltrate of eosinophils, histiocytes and multinucleated giant cells Photographic negative of pulmonary edema UpToDate Online 23

24 CEP: Mr. CD Additional infiltrate at L apex not seen on CXR CD has a PMH significant for asthma and presents with several weeks history of cough, fever, progressive breathlessness, wheezing and night sweats. Peripheral eosinophilic infiltrate at apex of R lung Courtesy of Dr. Phillip Boiselle, BIDMC 24

25 Hypersensitivity Pneumonitis (HP)

26 HP: Pathophysiology and Work-Up Pathophysiology variable inflammatory reaction to inhalation of organic or inorganic particulates by sensitized individuals Work-up Pulmonary function tests: restrictive or mixed pattern Arterial blood gases: mild hypoxemia Bronchoalveolar lavage: lymphocytosis High Resolution CT 26

27 HP Differential Diagnosis: Atypical pneumonia Congestive heart failure Other infiltrative lung disease: sarcoid Obstructive pulmonary disease 27

28 HP: HRCT Indications: gold standard for radiologic diagnosis of HP, since chest radiographs are normal in 87% of patients with this disease Findings: diffuse micronodular or reticular opacities most prominent in middle to upper lung zones ground glass attenuation focal air trapping fibrotic changes 28

29 Expiratory Film HP: Ms. PS Expiratory Film Ground glass attenuation PS has had several episodes fever, Atalectasis shortness of breath and pleuritic chest pain over the past year and presents with abrupt onset fever, chills, malaise, nausea, vomiting and shortness of breath. Diffuse bronchial wall thickening Air Trapping Courtesy of Dr. Eamon Kato, BIDMC 29

30 HP: Characteristics of the infiltrate Giant Cells Granulomas Lymphoplasmic infiltrate in peribronchiolar distribution UpToDate Online 30

31 Churg-Strauss Syndrome (CSS)

32 CSS: Pathophysiology and Work-Up Pathophysiology: systemic vasculitis, extravascular granulomas and prominent peripheral blood eosinophilia in patients with a history of asthma and/or allergy multisystem, but predominant sites of involvement = lung, skin, nervous system Work-Up: peripheral blood eosinophilia in range of /uL P-ANCA positivity elevated ESR elevated IgE surgical biopsy of lung or other involved organ demonstrating eosinophilic infiltrate, necrosis, giant cell vasculitis of small arteries and veins, necrotizing granulomas CXR HRCT 32

33 CSS Differential Diagnosis: asthma chronic eosinophilic pneumonia Wegener s granulomatosis lymphomatoid granulomatosis necrotizing sarcoid granulomatosis bronchocentric granulomatosis polyarteritis nodosum 33

34 CSS: Chest Radiographs Indications: findings are diverse, so more useful for monitoring of disease progression than for diagnosis Findings: most common is bilateral, patchy, multifocal opacities without lobar or segmental distribution interstitial or miliary opacities widespread shadowing from pulmonary hemorrhage bilateral, nodular disease hilar adenopathy pleural effusions 34

35 Indications: CSS: HRCT has been found to correlate with histological appearance of pulmonary parenchyma on open lung biopsy, so useful for diagnosis and monitoring Findings: diffuse, patchy opacities halo sign : centrilobular nodules within ground-glass glass opacity vasculitis sign : peripheral pulmonary arteries are enlarged and exhibit stellate and irregular configuration bronchial wall thickening and air-trapping 35

36 CSS: Mr. JD JD has a PMH significant for asthma and allergic rhinitis and presents with respiratory distress, tender subcutaneous nodules on the extensor surfaces of his arms, and abdominal pain. Diffuse, bilateral parenchymal consolidation Courtesy of Dr. Phillip Boiselle, BIDMC 36

37 CSS: Imaging Patterns: lobularsparing lobular Multifocal consolidation Choi et al, Chest,

38 CSS: Imaging Bronchial wall thickening Non-segmental consolidation Halo sign Choi, et al., Chest, Consolidation 38

39 Necrotizing granulomatous vasculitis CSS: Imaging Air-trapping Prominent blood vessels with irregular margin UpToDate Online Ground-glass opacity with centrilobular nodules Choi et al, Chest, Diffuse bronchial wall thickening 39

40 Conclusions Thoracic imaging can aid in diagnosis of atopic pulmonary disease. It is also useful for monitoring of disease progression. Chest radiographs exhibit many characteristic findings, but high-resolution computed tomography is more sensitive for detection of pulmonary pathology in these diseases. Thoracic imaging can correlate with histopathology, so may offer a less invasive alternative to surgical lung biopsy. 40

41 References Buschman,, DL and JA Waldron Jr. (1990). Churg-Strauss pulmonary vasculitis.. High-resolution computed tomography scanning and pathologic findings. Am Rev Respir Dis,, 142 (2): Choi,, YH et al. (2000). Thoracic Manifestation of Churg-Strauss Syndrome: Radiologic and Clinical Findings. Chest,, 117 (1): Grenier,, PA et al. (2002). New Frontiers in CT Imaging of Airway Disease. se. Eur Radiol,, 12: Kee,, ST et al. (1996). High-Resolution Computed Tomography of Airway Changes After Induced Bronchoconstriction and Bronchodilation in Asthmatic Volunteers. Acad Radiol,, 3: King, TE, Jr (2001). Classification and clinical manifestations of hypersensitivity sitivity pneumonitis (extrinsic allergic alveolitis). UpToDate Online. King, TE, Jr (2002). Churg-Strauss syndrome (allergic granulomatosis and angiitis). UpToDate Online. Lim, KG and PF Weller (2000). Allergic Bronchopulmonary Aspergillosis. UpToDate Online. Lynch, DA et al. (1992). Hypersensitivity pneumonitis: : sensitivity of high-resolution CT in a population-based study. Am J Roentgenol,, 159 (3): Lynch, DA (1998). Imaging of Asthma and Allergic Bronchopulmonary Mycosis. Radiologic Clinics of North America,, 36 (1): Stark, P (2002). High resolution computed tomography of the lungs. UpToDate Online. Ward, S et al. (1999). Accuracy of CT in the diagnosis of allergic bronchopulmonary aspergillosis in asthmatic patients. Am J Roentgenol,, 173 (4): Weller, PF and KG Lim (2002). Causes of Pulmonary Eosinophilia. UpToDate Online. 41

42 Acknowledgements Many thanks to: Phillip Boiselle,, MD Eamon Kato, MD Pamela Lepkowski Larry Barbaras our webmaster 42