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Radiological features of pneumonia

Radiological features of pneumonia Dr. Prithwiraj Maiti MBBS House Physician, Department of Internal Medicine R.G.Kar Medical College Admin and Founder, Pgblaster India Author of: A Pra ti al Ha d ook of Patholog “pe i e s a d “lides a d A Ulti ate Guide to Co u it Medi i e ; pu lished Ja pee Brothers, I dia Topics to be discussed:  Radiological anatomy of lung  Common radiological features of pneumonia 1. Staphylococcus aureus 2. Klebsiella pneumoniae 3. Mycoplasma pneumoniae 4. Pneumocystis carinii 5. Mycobacterium tuberculosis 6. Mycobacterium avium complex 7. Hydatid disease of lung 8. Allergic bronchopulmonary aspergillosis 9. Candida albicans 10. Bronchiectasis Radiological anatomy of right lung 2 fissures, 3 lobes Radiological anatomy of left lung 1 fissure, 2 lobes Common radiological features of pneumonia 1. 2. 3. 4. 5. Abnormal lung opacity Increase in the size and number of lung markings Silhouette signs: Loss of clarity of the diaphragm and heart borders Air bronchogram lines Spine sign: Loss of the normal darkening inferiorly of the thoracic vertebral bodies on the lateral view (suggesting lower lobe infection) 6. Opacification of the lung behind the heart shadow or below the diaphragms. Common radiological features of pneumonia 1. There is a dense opacity within the right upper lobe of the lung (arrowed) 2. There are also airbronchogram lines 3. There is increase in the number of bronchovascular markings 4. There is some loss of definition of the upper right heart border (silhouette sign). Spine sign: This image shows the vertebral bodies become lighter as we move down There is abnormal opacity behind the left (arrowed). This is caused by consolidation heart shadow (arrowed). There are air within the lower lobe. bronchogram lines. Staphylococcus aureus • Age group: Infants/ children • Characteristic pneumatoceles (thin walled cavities resulting from localized pulmonary destruction) • Bronchopneumonia • Multifocal and bilateral • Air bronchogram unusual • Lobar involvement unusual • In acute phase, it may cause cavitating pneumonia with pleural effusion • May cause hydrothorax/ hydropneumothorax. Klebsiella pneumoniae • Age group: Elderly patient • Upper lobe consolidation • Bulging fissure sign/ Bow fissure sign. Mycoplasma pneumoniae • Age group: 20-40 years • Initial stage: Unilateral lower lobe involvement beginning at hilum, fanning out to periphery • Late stage: Segmental, peribronchial involvement -> Lobar involvement. Pneumocystis carinii • Age group: Children as well as adults • Bilateral, symmetrical, diffuse, fine to medium reticular opacities • Sometimes solitary/ multiple miliary nodules/ thick walled nodules/ thin walled pneumatoceles are seen. Mycobacterium tuberculosis: Primary TB • Gho ’s co plex: Tuberculoma (caseating granuloma) near interlobar fissure + hilar lymph node enlargement • Ra ke’s co plex: When a Ghon's complex undergoes fibrosis and calcification with calcified draining lymphatics, it is called a Ranke complex. • Pleural/ pericardial involvement • Miliary/ extrapulmonary TB. Ra ke’s o ple Miliar TB Mycobacterium tuberculosis: Secondary TB • Acinar consolidation • Cavitation • Endobronchial spread • Miliary pattern. Arrow: Cavity, M: Miliary pattern Mycobacterium avium complex (MAC) • Nodules • Infiltration (patchy consolidation) • Cavity • Ectasia. [Mnemonic: NICE, 1 or more may be present] Hydatid disease of lung • Lung is the most common site of secondary involvement in children • Predominantly lower lobe involvement • Calcification of cyst wall rare • Rib/ vertebral erosion may occur. Signs in hydatid disease of lung Sign Cause Meniscus/ Double arch/ Crescent/ Moon sign Onion peel/ Cumbo sign Serpent sign Due to thin crescent of air in the uppermost of the cyst Water Lilly sign Cavity Due to air fluid level inside endocyst Collapsed membranes inside the cyst outlined by air Completely collapsed cyst floating on the cyst fluid All contents of cyst breaks out via communicating bronchus Radiological representation Allergic bronchopulmonary aspergillosis • Air cresce t/ Mo ad’s sig : Characteristic of aspergilloma -> Fungal ball with air crescent surrounding it. Allergic bronchopulmonary aspergillosis • Halo sign: Due to bleed in invasive aspergillosis. Candida albicans • Rarely occurs in severely immuno-compromised patients with leukemia/ lymphoma/ HIV patients • Widespread bilateral interstitial fluffy alveolar infiltrates; sometimes progressing to lobar consolidation. Bronchiectasis CXR: • Dilated bronchi • Tram track appearance HRCT: • Honeycombing Thank you…. Resources used: Radiology textbooks and Internet images.