More Related Content
Similar to Radiology Pulmonary Infections_Two.pptx
Similar to Radiology Pulmonary Infections_Two.pptx (20)
Recently uploaded
Recently uploaded (20)
Radiology Pulmonary Infections_Two.pptx
- 1. PULMONARY INFECTIONS MARY ANGELINE F. TWO
- 2. INFECTION IN THE NORMAL HOST Bronchopulmonary System Accessible to microorganisms Host Defense Mechanisms Pharynx, Trachea, and Central Bronchi Cellular and Humoral Immune Systems Pneumonia
- 3. MECHANISMS OF DISEASE & RADIOGRAPHIC PATTERNS 3 Routes of Entry: Via Tracheobronchial Tree Via Pulmonary Vasculature Via Direct Spread Mediastinum Chest Wall Upper Abdomen
- 4. INFECTION VIA TRACHEOBRONCHIAL TREE 3 Subtypes Lobar Pneumonia – starts within distal air spaces Spreads via Pores of Kohn and Canals of Lambert Nonsegmental consolidation Bronchopneumonia – most common pattern, typical of staphylococcal pneumonia Multifocal opacities, produce a “patchwork quilt” appearance Atypical Pneumonia – most often from viral and mycoplasma pulmonary infection Small airway thickening, irregular linear and nodal opacities Segmental and subsegmental atelectasis is common
- 5. ROUTES OF ENTRY Via Pulmonary Vasculature Usually occurs in Systemic Sepsis Pattern of parenchymal involvement is patchy and bilateral Lung bases are most severely involved Via Direct Spread Usually results in a localized parenchymal process adjacent to extrapulmonary source of infection Abscess formation may result
- 6. INFECTION IN THE NORMAL HOST Bacterial Pneumonia Viral Pneumonia Fungal Pneumonia Parasitic Infection
- 7. BACTERIAL PNEUMONIA Community-Acquired Bacterial Pneumonia S. pneumoniae M. pneumonia C. pneumoniae L. pneumophila
- 8. BACTERIAL PNEUMONIA Streptococcus pneumoniae (Pneumococcus) Most commonly isolated bacteria in patients w/ pneumonia who require hospitalization Tends to begin in the lower lobes or the posterior segments of the upper lobes. There is a rapid development of an airspace inflammatory exudate Typical radiographic appearance of acute pneumococcal pneumonia is Lobar Consolidation. Airspace opacification in the right upper lobe with air bronchograms
- 9. BACTERIAL PNEUMONIA In children and young adults, pneumococcal pneumonia may present as a spherical opacity (“round pneumonia’) simulating a parenchymal mass. Left lower lobe mass
- 10. BACTERIAL PNEUMONIA Staphylococcus aureus Cause nosocomial pneumonia May develop in patients w/ endocarditis or indwelling catheters and intravenous drug users. Typically produces a bronchopneumonia and appears radiographically as patchy opacities and may become confluent to produce lobar opacification. Air bronchograms are rarely seen Pneumatoceles Multifocal airspace opacification
- 11. BACTERIAL PNEUMONIA Klebsiella pneumoniae – appears as a homogenous lobar opacification containing air bronchograms. 3 features that distinguishes it from Pneumococcal Pneumonia: Volume of the involved lobe may be increased by the exudate, producing a bulging interlobar fissure An abscess may develop, w/ cavity formation Incidence of pleural effusion and empyema is higher Extensive right upper lobe consolidation, with bulging of the horizontal fissure.
- 12. BACTERIAL PNEUMONIA Haemophilus influenza Most often causes bronchitis May extend to produce bilateral lower lobe bronchopneumonia “Tree-in-bud pattern” Pseudomonas aeruginosa Pattern of involvement depends upon the method by which the organisms reach the lungs Pleural effusions are common, usually small Scattered centrilobular opacities In a tree-in-bud pattern Prominent mediastinal lymphadenopathy Multifocal lung consolidation bilaterally consistent with bronchopneumonia Cavitary necrosis w/in Right upper lobe consolidation Mild superimposed ground-glass opacity
- 13. BACTERIAL PNEUMONIA Legionella pneumophila Legionnaires disease Most commonly found in air conditioning and humidifier systems Characteristic radiographic pattern is airspace opacification Radiographic resolution is often prolonged and may lag behind symptomatic improvement Dense right upper lobe and superior segment right lower lobe airspace opacification
- 14. BACTERIAL PNEUMONIA Anaerobic Bacterial Infection Arise from aspiration of infected oropharyngeal contents Bacteroides and Fusobacterium Distribution of parenchymal opacities reflects the gravitational flow of aspirated material Typical radiographic appearance is peripheral lobular and segmental opacities Consolidated and atelectatic right lung containing a large abscess (arrow) and associated parapneumonic effusion
- 15. Actinomycosis Normal inhabitant of the oropharynx Most commonly follows dental extractions Lungs may be infected by aspiration or direct extension Radiographic findings often indistinguishable from that of nocardiosis Mycoplasma Displays both bacterial and viral characteristics Most common atypical pneumonia Fine reticular pattern – early stage May progress to patchy segmental ground-glass or airspace opacities Vague opacity projecting over the left first rib (arrow). Axial CT through the upper lungs shows an irregular mass with adjacent ground glass that extends posteriorly to create a broad area of contact with the pleural surface. Diffuse fine reticular opacities centrilobular and lobular areas of ground- glass opacity with associated bronchial wall thickening (arrowheads).
- 16. BACTERIAL PNEUMONIA Mycobacterium tuberculosis Aerobic acid-fast bacillus Primary TB Inflammation and enlargement lymph nodes is common Postprimary/Reactivation Hypersensitivity Caseous necrosis seen histologically Shows airspace disease within the anterior segment of the right upper lobe, with right hilar (solid arrow) and paratracheal (open arrow) lymph node enlargement.
- 17. Postprimary Tuberculosis Left apical cavitary disease (arrow) with associated left upper lo be volume loss Miliary TB
- 18. BACTERIAL PNEUMONIA Atypical Mycobacterial Infection Mycobacterium avium intracellulare (MAI) or Mycobacterium kansasii Typically affects patients w/ underlying lung disease Radiographic features often indistinguishable from reactivation TB Cavitation is common but effusion, lymph node enlargement and military spread are unusual. Right upper lobe volume loss with multiple cavities Irregular Right apical cavity w/ right cylindrical bronchiectasis, Small nodules, and tree-in-bud opacities
- 19. Mid and lower zone reticulonodular opacities
- 20. VIRAL PNEUMONIA Influenza Virus Most common cause Mostly confined to the upper respiratory tract Severe hemorrhagic pneumonia may develop Bilateral lower lobe patchy airspace opacification is often seen in adults Can have bacterial superinfection Bilateral fine reticular opacities with right lower lobe airspace opacification.
- 21. VIRAL PNEUMONIA RSV and Parainfluenza Virus Common causes of epidemic viral pneumonia in children Findings are similar to other viral pneumonias: patchy airspace opacities, bronchial wall thickening (particularly in RSV pneumonia) and centrilobular nodules and tree-in-bud opacities. Bronchopneumonia and bronchiolitis
- 22. Varicella Zoster May cause severe pneumonia Adenovirus Frequent cause of upper and occasionally lower respiratory tract infection Hyperinflation and bronchopneumonia accompanied by lobar atelectasis Healed Varicella Pneumonia. innumerable scattered calcified nodules. Patchy opacities (arrows) in both lungs
- 23. VIRAL PULMONARY INFECTION—COMMON ORGANISMS AND PATTERNS OF DISEASE
- 24. FUNGAL PNEUMONIA Histoplasmosis Coccidiodomycosis Blastomycosis Aspergillus
- 25. FUNGAL PNEUMONIA Histoplasmosis Majority of patients are asymptomatic Acute disease chest radiograph may be normal or w/ nonspecific changes Subsegmental airspace opacities May also result in a solitary nodule <3mm termed histoplasmoma Inhalation of large inoculum can produce widespread nodular opacities 3-4mm in diameter Most common in the lower lobes and frequently calcify Left mid-lung nodule (arrow) with associated left hilar enlargement (arrowhead). Irregular superior segment left lower lobe nodule (arrow) with ill- defined margins and an enlarged left hilum (arrowhead) reflecting lymph node enlargement
- 26. FUNGAL PNEUMONIA Coccidiodes Three Types: Acute – “valley fever” Chronic Disseminated Chest Radiograph may be normal or show focal or multifocal airspace or nodular opacities Hilar and mediastinal lymph node enlargement and pleural effusion may be seen Multiple right mid and lower lung and left basilar nodules (arrows)
- 27. FUNGAL PNEUMONIA Aspergillosis Responsible for a spectrum of pulmonary diseases in humans Aspergilloma is a fungus ball (mycetoma) that develops in a preexisting cavity in the lung parenchyma. Seen as solid round mass w/in an upper lobe cavity w/ an “air crescent” Progressive apical pleural thickening adjacent to a cavity is common Reveals left upper lobe volume loss, a left upper lobe mass (arrow) with associated apical pleural thickening (arrowheads)
- 28. PARASITIC INFECTION Uncommon Manifested either by: Direct invasion or Hypersensitivity reactions
- 29. PARASITIC INFECTION Amoebiasis Usually confined to the GI tract and liver Direct intrathoracic extension of infection from a hepatic abscess Right sided obliteration of costophrenic angle and displaced right lung Showed right sided pleural effusion with pocket mainly in lateral aspect and in the oblique fissure, multiple gas bubbles with air fluid levels, and partial atelectasis of right middle and lower lobes that are medially displaced
- 30. Echinococcus granulosus Cause Hydatid Disease of the lung Humans are accidental intermediate hosts Pulmonary echinococcal cysts Exocyst Endocyst Pericyst Well-circumscribed, spherical soft tissue masses masses Do not have calcified walls Predilection for the lower lobes and right side “Meniscus” or “crescent” sign “Sign of the Camalote” or “Water Lily” sign Cyst wall crumpled and floating within uncollapsed pericyst that produce the water-lily sign
- 31. PARASITIC INFECTIONS Paragonimiasis Acquired by eating raw crab or snails Patient may present w/ cough, hemoptysis, dyspnea, and fever Most common radiographic finding Multiple cysts w/ variable wall thickness Associated w/ focal atelectasis and subsegmental consolidation Dense linear opacities may be identified Effusions are common and may be massive Right lower lobe nodules and cavitary lesions Multiple nodules and airspace consolidation in the right lower lobe
- 32. PARASITIC INFECTIONS Schistosomiasis S. mansoni S. japonicum S. haematobium Presents radiographically as transient airspace opacities (eosinophilic pneumonia) Mature flukes produce ova which may embolize the lung Induces granulomatous inflammation and fibrosis which leads to an obliterative arteriolitis Radiographically, a diffuse fine reticular pattern is commonly seen Multiple small pulmonary nodules scattered over both lungs without obvious predilection.
- 33. PARASITIC INFECTIONS Dirofilariasis “dog heartworm” Can be transmitted from dogs to humans by mosquitoes Pulmonary involvement appears as an asymptomatic subpleural solitary pulmonary nodule Diagnosis is made on resection of the nodule (A) A nodular lesion in the right lung found incidentally on chest x ray. (B) Chest CT demonstrated a solitary pulmonary nodule in the right lower lobe. (C) PET also revealed a small subpleural nodule at the right lower lobe with minimal increased FDG uptake
Editor's Notes
- Infection via the tracheobronchial tree is generally secondary to inhalation or aspiration of infectious microorganisms and can be divided into three subtypes based on gross pathologic appearance and radiographic patterns: namely the lobar pneumonia, lobular or bronchopneumonia, and atypical pneumonia. As will be discussed in later sections, certain organisms will typically produce one of these three patterns, although there is also a considerable overlap. Lobar Pneumonia Is typical of pneumococcal pulmonary infection. In this pattern of disease, the inflammatory exudate begins within the distal airspaces, and then spreads via pores of kohn (which are apertures in the alveolar septum which allow communication between 2 alveolis) and canals of lambert (which are microscopic collateral airways between the distal bronchiolar tree and adjacent alveoli) to produce a nonsegmental consolidation. Bronchopneumonia - Is the most common pattern of disease and is most typical of staphylococcal pneumonia. In the early stages, the inflammation is centered primarily in and around the lobular bronchi, as it progresses, exudative fluid then extends peripherally along the bronchus to involve the entire lobule. Radiographically, it appears as multifocal opacities that are roughly lobular in configuration produce a “patchwork quilt” appearance because of the interspersion of normal and diseased lobules. Exudate within the bronchi accounts for the absence of air bronchograms in bronchopneumonia. With coalescence of affected areas, the pattern may resemble lobar pneumonia. Atypical Pneumonia - Is most often a result of viral and mycoplasma pulmonary infection, there is inflammatory thickening of bronchiolar and alveolar walls and the pulmonary interstitium. This results in a radiographic pattern of small airways thickening and irregular linear and nodular opacities which reflect a combination of small airways, alveolar and peripheral interstitial disease. Air bronchograms are absent because the alveolar spaces remain aerated. Segmental and subsegmental atelectasis from small airways obstruction is common .
- FIGURE 14.9. Postprimary (Reactivation) Tuberculosis. A: Frontal dual-energy subtraction chest radiograph in a 46-year-old woman shows Left apical cavitary disease (arrow) with associated left upper lobe volume loss. B, C: Contrast-enhanced coronal (B) and sagittal (C) CT scans show the left upper lobe consolidation (arrows) with dependent tree-in-bud opacities (circles) reflecting endobronchial spread of disease. Note additional superior segment left lower lobe cavity (curved arrow in C). Sputum cultures were positive for Mycobacterium tuberculosis. FIGURE 14.10. Miliary Tuberculosis. A: Coned-down view of a frontal radiograph demonstrates innumerable micronodular opacities characteristic of micronodular (miliary) interstitial disease. Transbronchial biopsy demonstrated caseating granulomas containing acid-fast bacilli. B: Coronal reformation at lung windows of a CT scan in another patient with proven miliary tuberculosis shows innumerable randomly distributed small lung nodules.
- FIGURE 14.12. Mycobacterium avium-intracellulare (MAI) Infection-Nodular Bronchiectatic Form. A: Frontal chest radiograph in a 54-year-old woman with MAI infection shows Mid and lower zone reticulonodular opacities. B, C: Axial (B) and coronal (C) CT scans show middle lobe, lingular and right lower lobe cylindrical bronchiectasis, tree-in-bud opacities, and nodules (arrowheads in B and C).
- Respiratory syncytial virus and parainfluenza virus are common causes of epidemic viral pneumonia in children. When seen in adults, the disease is usually in the setting of a debilitated or immunocompromised patient (Fig. 14.14) . Findings are similar to other viral pneumonias: patchy airspace opacities, bronchial wall thickening (particularly in RSV pneumonia) and centrilobular nodules and tree-in-bud opacities. Parainfluenza Virus Pneumonia. A, B: CT through upper lungs (A) and mid-lungs (B) in a patient with acute myelogenous leukemia (AML) shows striking bronchopneumonia and bronchiolitis (arrowheads). Parainfluenza virus was isolated from bronchoalveolar lavage fluid.