Pulmonary infections by Dr Farkhanda.pptx

Pulmonary Infections - Dr Farkhanda Jabeen

1. Pulmonary infections And Their Radiological Presentation

2. DR FARKHANDA JABEEN MBBS,FCPS (Diagnostic Radiology) FGPC Islamabad

3. Learning Objectives Types Etiology and Pattrens Complications of Pulmonary Infections. Radiological Presentations. Differential diagnosis.

4. Types.. Pneumonias: Infections caused by pathogenic organisms. Pneumonitis: Inflammatory process primarily involving the alveolar walls.

5. Pneumonias……. - Acute pneumonias -Chronic pneumoinas

6. Pneumonias……Etiology Bacterial Non bacterial Viral Fungal Metazoan Protozoan

7. Of the bacterial causes the pneumococcus (Streptococcus pneumoniae) is most common, with much smaller numbers of Staphylococcus aureus, Haemophilus influenzae, Klebsiella pneumoniae and Legionella pneumophila Usually cause Lobar and bronchopneumonia .

8. Pneumonias…… Of the non-bacterial causes….. Mycoplasma pneumoniae is most common. Other non-bacterial causes found in small numbers are Chlamydia psittaci (psittacosis) and Coxiella burnetii (Q fever).

9. Viral pneumonias…. The viruses are almost all influenza and cold viruses. Usually cause interstitial pneumonias Mixed infections are found in approximately 10% of cases.

10. Patterns of pneumonias …. Lobar pneumonias Bronchopneumonias Interstial pneumonia Atypical pneumonia Viral pneumonias

11. Lobar pneumonia….. Lobar pneumonia commences as a localized infection of terminal air spaces. Inflammatory edema spreads to adjacent lung via the terminal airways and pores of Kohn, and causes uniform consolidation of all or part of a lobe

12. Lobar pneumonia…. In lobar pneumonia the usual homogeneous lung opacification is limited by fissures and affected lobes retain normal volume and often show air bronchograms.

13. Bronchopneumonia….. When the consolidation is patchy and centered around the terminal bronchiole Bronchopneumonia is a multifocal process which commences in the terminal and respiratory bronchioles and tends to spread segmentaly . It may also be called lobular pneumonia, and produces patchy consolidation. The commonest causes are S. aureus and Gram-negative organisms.

14. BACTERIAL PNEUMONIAS …. --Streptococcus pneumonia. This is a common cause of pneumonia in all age groups, and particularly in young adults. Typically it produces lobar consolidation. which is often basal but may occur anywhere in the lung. The volume of the consolidated lung is normal, and an air bronchogram may be visible.

15. Streptococcal pneumonia…. Occasionally edema of the interlobular septa causes septal lines. Pleural effusion, empyema and cavitation are unusual if the infection is treated promptly, but may be seen in debilitated patients. Resolution is usually complete.

16. ( A) Pneumococcal pneumonia Lingular and right upper lobe consolidation with sparing of the apex. (B) CT image from a different patient demonstrating air bronchograms in an area of peripheral consolidation due to an organizing pneumonia

17. Staphylococcus aureus pneumonias. This is a common cause of pneumonia in debilitated patients. Haematogenous infection of the lungs may occur in septicemia, and is a common complication of intravenous drug abuse. When dissemination is haematogenous the typical appearance is of multiple poorly defined rounded nodules that develop rapidly over a few days. Usually cavitation is evident, especially on later examinations.

18. Staphylococcus aureus pneumonias When pneumonia occurs as a complication of intravenous drug abuse echocardiography should be undertaken since in most of these patients the source of septic emboli is an infective endocarditis on the tricuspid valve. Infection may also be the result of inhalation, typically causing a bronchopneumonia with multiple, patchy areas of consolidation Confluence of these areas may develop. Again cavitation is common, and in children pneumatoceles may develop. Pleural effusion, empyema and areas of atelectasis are common complications.

19. Complications of pneumonias…... Lung abscess Pneumatoceles Spread to pleural cavity…………. Empyema Spread to pericardial cavity ….. Suppurative pericarditis Bacteremia …………………………… metastatic abscesses

20. Staphylococcal bronchopneumonia. A pneumatocele has developed in the right upper lobe.

21. Staphylococcal pneumonia of the right upper lobe with abscess formation

22. (A) Hematogenous staphylococcal abscess formation in an intravenous drug abuser. There are multiple thin-walled cavities and an associated left pleural effusion. (B) Multiple large thin-walled pneumatoceles in a different intravenous drug abuser with staphylococcal tricuspid endocarditis

23. Klebsiella pneumonia……. This is due to Friedlӓnder’s bacillus and typically occurs in elderly debilitated men. There is usually lobar consolidation more often right sided, and frequently upper lobe. The volume of the affected lung is maintained, or may be increased causing bulging of the fissures . Cavitation is common A bronchopneumonic pattern may also occur

24. A, B) Klebsiella pneumonia. There is consolidation in the right lower lobe

25. (A, B) Klebsiella pneumonia. There is a large cavity in the right lower lobe following cavitation of pneumonic consolidation. An aortic valve replacement is present.

26. LUNG ABSCESS……. Suppuration and necrosis of pulmonary tissue may be due to tuberculosis, fungal infection, malignant tumour and infected cysts. However, the term lung abscess usually refers to a cavitating lesion secondary to infection by pyogenic bacteria. This is most frequently due to aspiration of infected material from the upper respiratory tract and is often associated with poor dental hygiene.

27. (A) Lung abscess(B) Several weeks later a thin-walled pneumatocele remains

28. Lung abscess…… Appearance of an air-fluid level indicates that a communication with the airways has developed. The wall of the abscess may be thick at first, but with further necrosis and coughing up of infected material it becomes thinner.

29. VIRAL PNEUMONIAS… Viral pneumonia usually commences in distal bronchi and bronchioles as an interstitial process with destruction of the epithelium, oedema and lymphocytic infiltration. There may also be focal inflammation of the terminal bronchioles and alveoli and progression to haemorrhagic pulmonary edema.

30. Viral pneumonias….. The radiological appearances of a viral pneumonia are very varied, but often include: 1. Peribronchial shadowing 2. Reticulonodular shadowing 3. Patchy or extensive consolidation

31. Viral pneumonia…. Viral pneumonia is uncommon in adults, unless the patient is immunocompromised. Most pneumonias that complicate viral infections in adults are due to bacterial superinfection. However, viral pneumonias are not rare in infants and children.

32. CMV pneumonia in a 2½-month-old child. There is reticular nodular shadowing throughout both lungs

33. Adenovirus chest infection There is reticulonodular infiltrate, most marked in a bronchovascular distribution at the right lower zone

34. Measles giant cell pneumonia. Extensive ill-defined opacities with air bronchograms. The changes are more marked on right side.

35. Herpes varicella zoster…. Varicella pneumonia occurs more often in adults than in children. In the acute phase of infection the chest radiograph may show widespread nodular shadows up to 1 cm in diameter, Clinically the pneumonia will be concurrent with the typical skin rash (Following recovery a small proportion of these nodules calcify and, if multiple, may produce a characteristic radiographic appearance. These patients are often able to give a history of severe chickenpox as an adult.

36. Multiple calcified varicella scars.

37. Aspiration And Inhalational Pneumonias… The effects of aspiration of particulate or liquid foreign material into the lungs are twofold: Those due to mechanical bronchial obstruction and Those due to the irritant properties of the aspirate. When the cough reflex is suppressed by stupor, alcohol or drugs, aspiration of food from the stomach during vomiting is likely to occur. The inflammatory response excited by vegetable matter is intense. And commonly followed by secondary infection with commensals and anaerobic organisms.

38. Aspiration pneumonias…. Aspiration of mineral oils results in lipoid pneumonia . The prolonged use of liquid paraffin for constipation is the usual cause . Precipitating factor is chronic oesophageal obstruction.

39. (A) Lipoid pneumonia. Aspiration of liquid paraffin (B) Eight years later there has been significant clearing but severe residual fibrosis is now present.

40. Mendelson's syndrome…. This is a chemical pneumonia caused by aspiration of acid gastric contents during anaesthesia . An intense bronchospasm is rapidly followed by a flood of oedema throughout the lungs, resulting in hypoxia and requiring high ventilation pressures. The radiographic appearance of massive pulmonary oedema taken together with the clinical presentation is pathognomonic

41. Mendelson's syndrome. Postoperative aspiration of gastric contents Note the subdiaphragmatic air following laparotomy.

42. Inhalation of irritant gases.. Inhalation of gases such as ammonia, chlorine and nitrogen dioxide produces an acute focal or diffuse pulmonary oedema followed by functional derangements indicative of bronchiolar and alveolar damage.

43. Atypical /Interstitial Pneumonias …… Inflammatory infiltration of the connective tissue framework of the lung is characteristic. On reaching the bronchial wall via the airways, they destroy the ciliated epithelium, with resulting edema and lymphocytic infiltration of the bronchial mucosa. There is subsequent spread of the inflammatory process to the interlobular septa. There also is lymphocytic infiltration of the peribronchial alveoli and this appears similar to lobular pneumonia.

44. Atypical pneumonias…. A variety of organisms may be responsible, the most important being Mycoplasma pneumoniae , but also including viruses, especially influenza viruses types A and B, respiratory syncytial virus and adenovirus, Chlamydia psittaci (psittacosis) and Coxiella burnetti (Q fever). The illness often manifests with systemic symptoms overshadowing those due to the pneumonia, and the course of disease may be less dramatic but more prolonged than with typical pneumonias.

45. Mycoplasma pneumonia. There is a patch of left mid zone consolidation obscuring the left heart border.

46. Pulmonary Tuberculosis…… Mycobacterium tuberculosis is responsible for most cases of tuberculosis; fewer than 5% of cases are caused by atypical mycobacteria. Infection is usually by inhalation of organisms from open cases of the disease. Transmission is by droplet inhalation, and the dose of viable organisms received is critical. Children, the immunocompromised, especially HIV-positive patients, and some immigrant groups are particularly susceptible.

47. Pulmonary tuberculosis…… Activation of the immune system usually leads to resolution, healing and fibrosis at this stage . Usually a fibrous capsule walls off the lesion and dystrophic calcification may occur. If the response to infection is weak the disease may progress and there is little difference between lesions of primary and post-primary evolution.

48. Primary pulmonary tuberculosis…… Most cases of primary pulmonary tuberculosis are subclinical. Commonly in a subpleural site in the well- ventilated lower lobes. There is an area of peripheral consolidation (the Ghon focus), and spread from this along the draining lymphatics may lead to enlargement of regional lymph nodes. This combination is referred to as a primary complex.

49. Consolidation in primary infection TB… This may involve any part of the lung, and the appearance is nonspecific unless there is coincidental lymphadenopathy. Healing is often complete without any sequelae on the chest radiograph although fibrosis and calcification may occur

50. CXR showing consolidation with ABGs left upper lung zone

51. Pulmonary tuberculosis… Lymphadenopathy is a common feature of primary infection, but is rare in post-primary tuberculosis except in the HIV-positive population. Enlarged lymph nodes may press on adjacent airways and cause pulmonary collapse or air trapping with hyperinflation . Caseating nodes may also erode into airways, causing bronchopneumonia, And into vessels causing miliary infection.

52. Healed tuberculosis. There is bilateral upper lobe fibrosis with elevation of both hila. Basal emphysema has developed. There are multiple calcified granulomas in the mid and upper zones.

53. Consolidation in post-primary infection This usually appears in the apex of an upper or lower lobe, and almost never in the anterior segments of the upper lobes. The consolidation is often patchy and nodular and may be bilateral.

54. Post primary tuberculosis… The consolidation is often patchy and nodular and may be bilateral Progressive infection is indicated by coalescence of consolidation, and the development of cavities Simultaneously there may be fibrosis and volume loss indicating healing .

55. Areas of bronchiectasis and emphysema may develop. Healed lesions often calcify. Because the upper lobes are predominantly involved, the effects of fibrotic contraction are seen as the trachea being pulled away from the midline. elevation of the hila and distortion of the lung parenchyma

56. Tuberculosis (A, B) Chest radiograph and CT scan demonstrating almost complete destruction of the right lung due to pulmonary tuberculosis The CT reveals bronchopneumonic spread to the opposite lung.

57. Miliary tuberculosis This is due to hematogenous spread of infection and may be seen in both primary and post-primary disease. In the former the patient is often a child, and in the latter case the patients are often elderly, debilitated or immunocompromised.

58. Milliary tuberculosis….. At first CXR mat be normal, but then small, discrete nodules, 1−2 mm in diameter, become apparent, evenly distributed throughout both lungs These nodules may enlarge and coalesce, but with adequate treatment they slowly resolve. Occasionally, some may calcify.

59. Tuberculoma This is a localized granuloma due to either primary or post-primary infection It usually presents as a solitary well-defined nodule, up to 5 cm in diameter. Calcification is common but cavitation is unusual

60. Tuberculoma. A well-defined cavity is projected adjacent to the right hilum.

61. Lymphadenopathy Hilar and mediastinal lymphadenopathy is a common feature of primary infection and may be seen in the presence or absence of peripheral consolidation. Following healing, involved nodes may calcify. Lymphadenopathy is usually unilateral but may be bilateral.

62. Pleural changes Pleural effusion complicating primary infection is usually unilateral and due to subpleural infection. Pulmonary consolidation and/or lymphadenopathy may or may not be apparent. At presentation the effusion may be large and relatively asymptomatic These effusions usually resolve without complication. P

63. Pleural effusion in post- primary infection, however, often progresses to empyema. Healing is then complicated by pleural thickening and often calcification. Uncommon complications of tuberculous empyema are bronchopleural fistula, osteitis of a rib, pleurocutaneous fistula and secondary infection. Pleural thickening over the apex of the lung often accompanies the fibrosis of healing apical tuberculosis. Pneumothorax may complicate subpleural cavitatory disease.

64. Tuberculosis. There is generalised pleural thickening with extensive pleural calcification

65. Airway involvement This may be secondary to lymphadenopathy or endobronchial infection and may therefore complicate both primary and post- primary disease. Compression of central airways by enlarged nodes may cause pulmonary collapse or air trapping. Healing of endobronchial infection with fibrosis may also result in bronchostenosis . The lung distal to bronchial narrowing may develop bronchiectasis.

66. Fungal infections Commonest fungal infections are.. Aspergillosis Histoplasmosis Coccidioidomycosis Mucormycosis

67. Aspergillosis….. Aspergillus fumigatus is widespread in the atmosphere and it is inevitable that man inhales the spores from time to time. It is capable of multiplying in air passages when the conditions are favourable . The pulmonary manifestations are grouped into three categories.

68. 1- Aspergilloma Any chronic pulmonary cavity may be colonised by fungus. Such cavities are mostly secondary to tuberculosis, histoplasmosis or sarcoidosis, and are, therefore, usually in the upper lobes. The fungal hyphae form a ball or mycetoma which lies free in the cavity. The chest radiograph may show a density surrounded by air within a cavity.

69. Aspergilloma… By altering the position of the patient the ball is seen to be mobile. There is almost always pleural thickening related to the mycetoma. The differential diagnosis of a mycetoma in a cavity includes blood clot, cavitating tumour , lung abscess and hydatid cyst.

70. Mycetomas are associated with development of vascular granulation tissue in the cavity wall, which may bleed. Life-threatening haemoptysis may be difficult to treat surgically, and may be better managed by bronchial or intercostal artery embolisation .

71. Right apical aspergilloma in a patient with previous TB Note the mycetoma material lying free in the dependent part of the cavity as well as the nodules adherent to the cavity walls anteriorly

72. 2 .-Invasive aspergillosis…… In immunocompromised individuals Aspergillus may cause primary infection of the lung. This may be a bronchopneumonia, lobar consolidation or multiple nodules . On high-resolution CT scanning a halo of increased attenuation in the surrounding lung may be seen . Histologically this corresponds to surrounding haemorrhagic inflammation, and although this finding on CT scanning is not completely diagnostic, it is highly suggestive. Cavitation is common, and following bone marrow transplantation often occurs when the white-cell count recover.

73. Invasive aspergillosis. There is widespread broncho pneumonic change in a patient receiving chemotherapy for oat cell carcinoma

74. Invasive aspergillosis. HRCT through a left upper lobe nodule demonstrating a halo of increased attenuation. Pathologically this correlates with a surrounding zone of haemorrhagic necrosis

75. 3- Allergic bronchopulmonary aspergillosis Aspergillus is the commonest cause of pulmonary eosinophilia The patient is usually an asthmatic in whom the fungus has colonised the lobar and segmental bronchi . Patients present with a cough and wheeze and often expectorate mucus plugs which contain fungi. In the acute phase the chest radiograph shows patchy consolidation, often in the upper zones. Mucus plugging may cause lobar collapse and dilated mucus-filled, thick walled bronchi visible as finger-like, tubular/branching opacities.

76. Asthmatic with allergic bronchopulmonary aspergillosis. Mucus plugging has resulted in collapse of the right upper lobe. Complete resolution followed treatment

77. Allergic bronchopulmonary aspergillosis. HRCT scan demonstrating finger-like opacities due to dilated mucus-filled bronchi

78. Allergic bronchopulmonary aspergillosis. HRCT demonstrating widespread bronchiectasis of the medium and large airways

79. METAZOAN INFECTIONS L oeffler's syndrome. This may be caused by many parasitic worms, including Ascaris,Taenia , Ankylostoma and Strongyloides , all of which may lodge in or migrate through the lungs at some stage of their life cycles. The term Loeffler's syndrome is now applied to almost any transient pulmonary opacities of a predominantly eosinophilic histology associated with a blood eosinophilia. The heavier the infestation the more profuse are the pulmonary lesions.

80. Metazoan infections.. Schistosomiasis Paragonimiasis Hydatid disease Armillifer armillatus

81. Protzoan infection….. Pneumocystis pneumonia Toxoplasmosis Entamoeba histolytica

82. CONGENITAL ABNORMALITIES THAT PREDISPOSE TO PULMONARY INFECTION Cystic fibrosis Hypogammaglobulinimeia Young’s disease Congenital pulmonary sequestration Congenital dyskinetic ciliary syndrome

83. Pulmonary sequestration. (A) The chest radiograph demonstrates a cavitating mass-like lesion in the right lower lobe. Note the preservation of the heart border and diaphragm. (B) Angiogram demonstrating the typical blood supply from a side branch of the sub diphragmatic aorta.

84. ACQUIRED CONDITIONS THAT PREDISPOSE TO PULMONARY INFECTION Systemic conditions that are associated with decreased immunity include old age, poor nutrition, diabetes, alcoholism, connective tissue disorders, many malignant diseases and AIDS. Iatrogenic causes include cancer chemotherapy, steroids, immunosuppression following organ transplantation, and radiotherapy.

85. PULMONARY INFECTIONS IN IMMUNOCOMPROMISED PATIENTS—NON-AIDS. Bacterial Candidiasis Mycobactrial Invasive aspergillosis

86. ACQUIRED IMMUNE DEFICIENCY SYNDROME PNEUMOCYSTIS CARINII PNEUMONIA (PCP) This protozoal infection occurs in all groups of immunocompromised patients with reduced cell-mediated immunity. It is particularly common in the AIDS population and remains the most common opportunistic infection.

87. PNEUMOCYSTIS CARINII PNEUMONIA (PCP) The radio- graphic appearances may be normal early in the disease in up to 10% of patients and the degree of dyspnoea may be in advance of the radiographic changes. Most patients will develop perihilar and mid and lower zone bilateral interstitial or ground-glass infiltrate.

88. PCP pneumonia… This may rapidly progress to involve the entire lung. On HRCT scanning the characteristic appearances are of a ground-glass infiltrate extending from the hilar regions into the surrounding lung, occasionally demonstrating a geographical pattern. Cavities, usually thin walled, but occasionally with a wall up to several milli metres in thickness, may develop.

89. PCP pneumonias… Many less common manifestations of PCP are well recognised and include; milliary disease, discrete pulmonary nodules, pleural effusions, and mediastinal lymphadenopathy. Mediastinal lymph nodes may become calcified and are particularly well seen on CT scanning.

90. Pneumocystis carinii pneumonia HRCT image through the upper lung zones demonstrating bronchocentric ground-glass infiltrate.

91. HRCT scan through the lungs demonstrating multiple areas of cystic destruction following repeated Pneumocystis infection

92. CXR showing ? Collapse Consolidation Pleural effusion lymphadenopathy

93. CXR showing? Pleural effusion Consolidation Lympadenopathy Bronchopneumonia pleural thickening

94. CXR ? Lymphadenopathy Bronchpneumonia Lobar pneumonia Pleural effusion collapse

95. CXR showing ? Pleural effusion Lobar pneumonia with bulging fissure bronchopneumonia with bulging fissure lymphadenopathy

96. CXR showing? Lobar pneumonia Bronchopneumonia Post primary tuberculosis Primary tuber culosis Pleural efuusion