Lung abscess

Professor Dr. Md Khairul Hassan Jessy
Professor of Respiratory Medicine
National Institute of Diseases of The Chest & Hospital, Mohakhali, Dhaka
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1. Lung Abscess Professor Dr. Md Khairul Hassan Jessy Professor of Respiratory Medicine National Institute of Diseases of The Chest & Hospital, Mohakhali , Dhaka

2. He feeds his wife every morning when he visits her at the nursing home. She hasn’t recognized him in five years due to her Alzheimer's. When he was asked, ‘if she doesn’t know who you are , why do you go?’ He smiled and said, ‘she doesn’t know who I am, but I know who she is!’

3. Background Failure to recognize & treat lung abscess is associated with poor clinical outcome Lung abscess was a devastating disease in the pre-antibiotic era when 1/3 of the patients died Another 1/3 recovered The remainder developed debilitating illnesses (i.e. Recurrent abscesses, chronic empyema , bronchiectasis ).

4. Background… In the early post-antibiotic period, sulfonamides didn’t improve the out-come of patients with lung abscess until the penicillin's & tetracycline's were available. Although resectional surgery was often considered a treatment option in the past, the role of surgery has greatly diminished over time coz most patients with uncomplicated lung abscess eventually respond to prolonged antibiotic therapy.

5. Definition A lung abscess is a localized area of destruction of lung parenchyma ( usually >2 cm in diameter ) in which infection by pyogenic organisms results in tissue necrosis and suppuration manifested radiologically as a cavity with air fluid level.

6. Classification Lung abscess may be single or multiple and they frequently contain air-fluid levels When multiple and small (<2 cm in diameter) they are sometimes referred to as necrotizing or suppurative pneumonia The formation of multiple small (< 2 cm) abscesses is occasionally referred to as necrotizing pneumonia or lung gangrene

7. Classification… Lung abscesses can be classified based on the duration & the likely etiology Acute abscess Chronic abscess

8. Classification… Clinically useful during initial evaluation Acute: A lung abscess is defined as acute if the patient presents with symptoms of < 2 weeks duration. Patients with an acute lung abscess are less likely to have an underlying neoplasm, but are more likely to have an infection caused by a virulent aerobic bacterial agent (e.g. S. aureus )

9. Acute Lung Abscess CXR of a patient who had foul-smelling & bad tasting sputum, an almost diagnostic feature of anaerobic lung abscess

10. Large right lower lobe abscess demonstrating air-fluid level

11. Classification… Clinically useful during initial evaluation Chronic: A chronic lung abscess is defined by symptoms lasting for > 4 to 6 weeks. Patients more like to have an underlying neoplasm or infection with a less virulent anaerobic agent

12. Classification…

13. Sequelae of malignant lung abscess of 64years old man

14. Classification… Primary abscess is infectious in origin, caused by aspiration or pneumonia in the healthy host. Mostly result from necrosis in an existing parenchymal process, usually untreated or aspiration pneumonia

15. Classification… Secondary abscess is caused by Pre-existing condition eg bronchiectasis Bronchial obstruction ( eg - aspirated foreign body) An immuno -compromised state Spread from an extra-pulmonary site Abscess that complicates either a septic vascular embolus ( eg - right sided endocarditis )

16. Classification… Lung abscesses can be further characterized by the responsible pathogen , such as Staphylococcus lung abscess & anaerobic or Aspergillus lung abscess. Most common anaerobe identified was Prevotella species. Most common aerobes identified were S. viridans , Staphyloccus species.

17. Classification… In a series of patients with acute community acquired lung abscess anaerobes isolated alone in 44% cases mixed aerobes & anaerobes in 22% aerobes alone in 19% the remaining cases were caused by an unidentified pathogens or M. tuberculosis

18. Classification… Multiple lung abscess? Staphyloccal

19. Classification… Multiple lung abscess? staphyloccal

20. Frequency In United States: The exact frequency in the general population is not known In Bangladesh: The exact frequency in the general population is not known

21. Demographic Profile Age Lung abscesses likely to occur more commonly in elderly patients because of Increased incidence of periodontal disease Increased prevalence of dysphagia Aspiration Sex A male predominance is reported in published case series.

22. Common sites Abscesses generally develop in the right lung Posterior segment of the right upper lobe is affected most commonly Followed by the apical segment of either lower lobe or both. If the patient is lying on his/her side The posterolateral parts of the upper lobe tend to receive the aspirate When aspiration has occurred with the patient lying supine The apical segments of the lower lobes tend to receive the aspirate

23. A 42 yr man developed fever & production of foul-smelling sputum. He had H/O heavy alcohol use & poor dentition. CXR shows lung abscess in the post segment of the Right upper lobe Pneumococcal pneumonia complicated by lung necrosis & abscess formation

24. Association with neoplasia Neoplastic 8-18% of lung abscess are associated with neoplasms in all age groups (approx 30% in patients > 45 yrs) Primary squamous cell carcinoma is the malignancy most often associated with abscess formation Others include Metastatic carcinoma (Colorectal carcinoma, Renal cell carcinoma) Lymphoma (Hodgkin’s disease)

25. কখন বুঝবে একটি দেশ ও সমাজ নষ্ট হয়ে গেছে, যখন দেখবে দরিদ্ররা ধৈর্যহারা হয়ে গেছে, ধনীরা কৃপন হয়ে গেছে, মুর্খরা মঞ্চে বসে আছে, জ্ঞানীরা পালিয়ে যাচ্ছে এবং শাসকরা মিথ্যা কথা বলছে। হযরত আলী (রাঃ)

26. বস্ত ু ত নিন্দা না থাকিলে পৃথিবীতে জীবনের গৌরব কি থাকিত? একটা ভাল কাজে হাত দিলাম, তাহার নিন্দা কেহ করে না, সে ভাল কাজের দাম কী। একটা ভাল কিছু লি খিলাম, তাহার নিন্দুক কেহ নাই, ভাল গ্রন্হের পক্ষে এমন মর্মান্তিক আদর আর কী হইতে পারে !

27. Causes of Lung abscess

28. Causes of Lung abscess (A) Aspiration Aspiration of infected material containing oropharyngeal flora (commonest cause) Organisms are anaerobic and aerobic May be due to Dental/ periodontal sepsis esp following tooth extraction, tonsillectomy and nasal operation Paranasal sinus infection

29. Causes of Lung abscess (A) Aspiration… Depressed conscious level /Unconscious patient Alcoholism/ Sedative drug abuse Anaesthesia (General) Epilepsy/seizure disorders Head injury Cerebrovascular accident (CVA) Diabetic coma Other prostrating illness

30. Causes of Lung abscess (A) Aspiration… Disturbances of swallowing Oesophageal stricture (benign or malignant) Oesophageal motility disorders ( eg - Systemic sclerosis, Neuromuscular disease, eg - bulbar/ pseudobulbar palsy, myasthenia gravis, amyotrophic lateral sclerosis) Achalasia of cardia Pharyngeal pouch Neck surgery Tooth extraction Tonsillectomy

31. Causes of Lung abscess (A) Aspiration… Delayed gastric emptying/ gastro- oesophageal reflux/ protracted vomiting Impaired laryngeal closure Tracheostomy tube Cuffed endotracheal tube Recurrent laryngeal nerve palsy

32. Causes… B) Necrotizing Pneumonia / Inadequately Treated Pneumonia Aerobic bacteria ( eg - Staphylococcus aureus , Strepto . Pneumoniae , Streptococcus milleri / intermedius , Klebsiella pneumoniae , Pseudomonas aeruginosa ) Anaerobic bacteria Others: Mycobacteria Fungal Parasites

33. Causes… C) Mechanical Bronchial obstruction by Tumour (Bronchial carcinoma/ Adenoma) Foreign body Enlarged lymph nodes Congenital abnormality – bronchial stenosis D) Pre-existing lung disease Bronchiectasis Cystic fibrosis

34. Causes… E) Haematogenous spread from a distal site [from other infection as septic emboli] Urinary tract infection Abdominal sepsis Pelvic sepsis Infective endocarditis (right-sided) Intravenous drug abuse Infected IV cannulae Septic thrombophlebitis Salpingitis Appendicitis Pyaemia / Septicaemia

35. Causes… F) Extension from extra-pulmonary abscess/ ( transdiaphragmatic spread) liver abscess subphrenic abscess Mediastinal abscess G) Trauma/ Post traumatic Infected pulmonary haematoma Contaminated foreign body H) Immunodeficiency Primary or Acquired

36. Causes… I) Infected pulmonary infarct Septic pulmonary emboli and pulmonary infarction by Strepto . pneumoniae Staph. aureus H. influenzae Anaerobic

37. RISK FACTORS FOR GRAM NEGATIVE COLONIZATION Malnutrition Severe illness Coma Intubation Diabetes Prior surgery Lung disease Renal failure Prior antibiotic use Hypotension Cigarette smoking Prolonged hospitalization

38. Pathology

39. Pathology Lung abscesses begin as areas of pneumonia in which small zones of necrosis (or microabscesses ) develop within the consolidated lung. Some of these areas coalesce to form single or sometimes multiple areas of suppuration that, when they reach an arbitrary size of 1-2 cm in diameter, are customarily referred to as abscesses. If natural history of this pathological process is interrupted at an early stage by appropriate antimicrobial treatment, then healing may be complete with no residual radiographic evidence of damage. However, if treatment is delayed or inadequate, the inflammatory process may progress, entering a more chronic phase.

40. Pathology… Bronchi adjacent to the area of inflammation may become eroded so that part of the purulent contents of the abscess may be expectorated as foul sputum. Fibrosis may occur in and around the abscess cavity, which may become loculated and walled off by dense scar tissue. Spillage of pus into the bronchial tree may serve to disseminate infection either to other parts of the same lung or to the opposite lung.

41. Pathology… The extent to which this suppurative process continues can be checked by antibiotics. These may sterilize the abscess cavity so that granulation tissue forms over the fibrous tissue, this then becoming covered by squamous or ciliated columnar epithelium that grows in form adjacent bronchi. Abscesses arising as a result of aspiration usually occur close to the visceral pleural surface in dependent parts of the lungs. In a study by Brock, it has been shown that three-quarters of lung abscesses occur in the posterior segment of the right upper lobe or the apical segments of the either lower lobe (due to anatomical disposition, these segmental bronchi accept the passage of aspirated liquid in the supine position most readily).

42. Pathology… Lung abscess that occur as a result of haematogenous spread may be found in any part of the lungs. Despite the close proximity of lung abscesses to the visceral pleura, resultant empyema is not the rule, occurring in less than one-third of cases.

43. Organisms Commonly Isolated

44. Organisms commonly isolated… Anaerobes – are usually part of a polymicrobial flora . Anaerobic bacterial commonly cause necrotizing pneumonia. Either as primary pathogen Or in combination with aerobic bacteria. The main groups of anaerobes are as follows. 1 Gram-negative bacilli making up the genus Bacteroides, notably Bacteroides fragilis . Prevotella and Porphyromonas . 2 Gram-positive cocci , mainly Peptostreptococcus and anaerobic or microaerophilic streptococci. 3 Long thin Gram-negative rods comprising Fusobacterium species, particularly F. nucleatum and F. necrophorum .

45. Organisms commonly isolated… Aerobic: Aerobic organisms tend to cause lung abscesses as part of a necrotizing pneumonia that can be seen to be radiographically more diffuse than is the case with classical anaerobic lung abscess, in which the surrounding lung parenchyma may appear relatively normal on the chest film. Gram-positive aerobes Staph. aureus , Strep. pyogenes (syn. Group A streptococcus, β haemolytic streptococcus) , Strep. pneumoniae , Strep. intermedius , Strep. constellatus and Strep. Anginosus . Gram-negative aerobes Klebsiella pneumoniae , Pseudomonas aeruginosa , Haemophilus influenzae , Escherichia coli , Acinetobacter species, Proteus species and Legionella species.

46. Organisms commonly isolated… Mixed – Common In majority of cases, a mixed bacterial flora can be found. Mycobacteria (rare) Mycobacterium tuberculosis Mycobacterium kansasii Mycobacterium intracellularis Fungus Histoplasmosis Aspergillosis Coccidiodes Cryptococcus Parasites Entamoeba histolytica Paragonimus westermanii

47. A thick-walled lung abscess

48. Histology of a lung abscess shows dense inflammatory reaction (low power & high power).

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50. Symptoms/ Signs

51. Symptoms The presenting features of lung abscesses vary considerably Presentation may be indolent over several weeks or months or acute A subacute onset may be associated with presumed aspiration

52. Symptoms … The illness also tends to be more abrupt and severe when lung abscesses arise as a consequence of necrotizing pneumonia caused by predominantly aerobic organisms ( eg - Staph. a ureus or K. pneumoniae )

53. Symptoms … Patients present with Severe cough with Profuse foul smelling sputum, may be foetid There may be large amounts of purulent sputum once a bronchial communication has been established Putrid sputum is a highly specific symptoms that is pathognomonic for anaerobic infection although present in only 50-60% of patients Haemoptysis (25% of patients) – not uncommon and may be life-threatening

54. Symptoms … Chest pain ( pleuritic or deep-seated aching discomfort) – 60% of patients Fever – usually high with chill & rigor, profuse night sweating Constitutional upset like- malaise, weakness Weight loss (60% of patients) – with an average loss of between 15 & 20 lbs Anorexia Symptoms of associated disease process eg - Bronchial obstruction due to lung cancer Oesophageal obstruction due to achalasia Right-sided endocarditis Dyspnoea

55. Symptoms … In most patients, presentation is insidious with symptoms lasting at least 2 weeks before presentation History Includes risk factors for aspiration, eg - Alcoholism Drug overdose Seizures Head injury Stroke Absence of such risk factors should prompt a search for a diagnosis other than primary lung abscess

56. Signs There is no signs specific for lung abscess Patient is toxic with high temperature & Halitosis Clubbing may develop within few weeks if treatment is inadequate usually in 10% cases after 3 weeks

57. Signs… On chest exam Evidence of consolidation Dullness to percussion and diminished breath sounds, if the abscess is large and situated near the surface of the lung The ‘ amorphic ’ or ‘cavernous’ breath sound traditionally associated with lung cavities are rarely elicited in modern practice

58. Features Of Severe Aspiration Pneumonia Respiratory rate >30 breaths/min Chest radiographic findings 50% increase in the infiltrate in 48 hours Bilateral multilobar involvement Presence of shock Urine output <<20 mL /h SIRS (systemic inflammatory response syndrome) or need for vasopressors to support blood pressure Severe lung injury (PaO2/FIO2 ratio <<250 mm Hg) Acute renal failure requiring dialysis

59. Investigations

60. Investigations 1.CBC 2.X-ray chest P/A view & lateral view 3.Sputum examination : Gram staining C/S (aerobic & anaerobic) AFB, fungus & malignant cells 4.FOB 5.CT scan of chest in some cases 6.Blood sugar

61. Investigations CBC Neutrophilic Leukocytosis WBC count may exceed 20,000 Elevated ESR Anaemia of chronic inflammation

62. Imaging studies

63. Imaging Studies… X-ray chest Radiographic abnormality may start with a pneumonic infiltrate followed by the development of one or more spherical areas of more homogeneous density in which air-fluid levels often arise indicating the formation of a bronchial communication

64. Imaging Studies Cavity with air-fluid level is seen after burst More on right side CXR Lung abscess as a result of aspiration most frequently occur in the posterior segments of the upper lobes or the superior segments of the lower lobe.

65. Abscess cavities may be large and are sometimes multilocular with several different fluid levels within one opacity

66. Abscess cavities/ multilocular

67. Imaging Studies The abscess may extend to the pleural surface, in which case it forms acute angles with the pleural surface Up to one third of lung abscesses may be accompanied by an empyema

68. CT scan of the thorax (right upper lobe) shows a thick-walled cavity with surrounding consolidation.

69. Imaging Studies/ carcinoma The cavity wall can be smooth or ragged but less commonly nodular which raises the possibility of cavitating carcinoma carcinoma Size of the cavity may be helpful in distinguishing neoplastic from non- neoplastic lung abscesses Minimal inflammation surrounding the abscess on radiographs suggest an underlying neoplasm Bronchial carcinoma & lung abscess may coexist in as many as 12% of cases

70. Imaging Studies If a lung abscess fails to communicate with a bronchus, the characteristic air-fluid level within a cavity will not be seen radiographically in this case, the radiographic appearance is one of a focal, ground-glass infiltrate with indistinct borders This may be seen early in the disease because it takes 8 to 14 days for tissue necrosis with abscess formation to develop However, tissue breakdown should be evident

71. Imaging Studies As a lung abscess heals, first the pneumonic infiltrate resolves during this process the wall of the abscess cavity typically becomes thinner diminishing in size until it is no longer detectable

72. Imaging Studies The wall thickness of a lung abscess progresses from thick to thin and from ill-defined to well-circumscribed as the surrounding lung infection resolves

73. Imaging Studies In a study of 71 patients 13% of lung abscess cavities had disappeared in 2 weeks 44% in 4 weeks 59% in 6 weeks and 70% within 3 months after treatment with appropriate antibiotics There is residual chest radiographic shadowing when extensive fibrosis has occurred

74. Imaging Studies Rarely multiple cavities on CXR, a rare findings in an anaerobic process may be complicated by immunosuppression , recurrent aspiration or virulent anaerobe(s) causing a necrotizing pneumonitis Occasionally, the radiographic features of complications may be evident, including – effusion, empyema, pneumothorax etc

75. Imaging Studies/ Thoracic CT Better in lung anatomy visualization to identify empyema from lung abscess An abscess is rounded radio-lucent lesion with a thin wall & ill-defined irregular margins

76. Imaging Studies/ Thoracic CT Thoracic CT may be very helpful in accurately defining the extent and disposition of both lung abscesses and empyemas Also may demonstrate the multiple small air cavities of necrotizing pneumonia Ultrasound or CT may also be helpful in guiding percutaneous diagnostic thin-needle aspiration of lung abscesses

77. Imaging Studies When the CXR cannot distinguish lung abscess from infected bulla/ empyema CT suggests A lung abscess is a thick, irregular walled cavity with no associated lung compression Empyema usually is characterized by thin, smooth walls with compression of uninvolved lung

78. Imaging Studies Infected bulla usually is characterized by thin, smooth walls with compression of uninvolved lung minimal surrounding inflammation

79. Lung abscess Empyema Infected bullae is a thick, irregular walled cavity with no associated lung compression lung usually is characterized by thin, smooth walls with compression of uninvolved lung usually is characterized by thin, smooth walls with compression of uninvolved lung minimal surrounding inflammation

80. Lung abscess

81. Lung Abscess

82. Criteria For Fiberoptic Bronchoscopy In Patients With Lung Abscess Atypical presentation Absence of fever White blood cell count << 11,000/mm3 Absence of systemic symptoms Fulminant course Absence of predisposing factors for aspiration Atypical abscess location Abscess formation in an edentulous patient Failure to respond to antibiotics Mediastinal adenopathy Suspected underlying malignancy Suspected foreign body

83. Investigations/FOB ( Contd ) Criteria for Bronchoscopy to exclude an underlying carcinoma in patients with lung cavities Mean oral temp <100 ºF Absence of systemic symptoms Absence of predisposing factors for aspiration, and Mean leukocyte count <11000/ mm3 When more than 3 of these factors are present in a patient with lung abscess, an underlying carcinoma is likely

84. Investigations/FOB ( Contd ) Bronchoscope is no longer routinely used for abscess drainage, because the majority spontaneously communicate with the airways & drain It is also possible to rupture an abscess during bronchoscopy and communicate previously uninvolved lung segment

85. Investigations…/ Sputum examination Sputum examination Gram staining & C/S (both aerobic & anaerobic) Repeated isolation of a predominant organism suggests that this may be a true pathogen ZN stain for AFB and AFB C/S GXP for MTB/Rif cytology for malignant cell Stain and culture for Fungus

86. Investigations Blood culture may be helpful in establishing the etiology If abscess is associated with an empyema (as in the case 30% of the time), culture of empyema fluid may yield reliable bacteriological data

87. Investigations ( Contd ) Blood cultures should be taken, as pathogens are occasionally isolated in cases of blood-borne (or ‘metastatic’) lung abscess or when the abscess has complicated pneumonia. Positive blood cultures are unusual in anaerobic infection. Serology may sometimes be helpful, especially to exclude hydatid disease or amoebiasis . More invasive methods of microbiological diagnosis ( transtracheal aspiration & bronchoscopy ) are rarely used, esp. if the presentation is atypical or the patient is not responding to therapy.

88. Investigations ( Contd ) Other methods of obtaining specimens CT/ USG guided Percutaneous needle aspiration /FNAC of a lung abscess FOB for Bronchoalveolar lavage , brushing & biopsy Pleural fluid aspiration (if empyema present)

89. Characteristics of sputum in lung abscess If the sputum is kept in a bottle, there are 3 layers Upper – Frothy Middle – thick liquid Lower – sediment (epithelial debris, bacteria)

90. Differential diagnosis

91. Differential diagnosis/ Clinically Consolidation (during resolution stage), usually no clubbing Bronchiectasis Bronchial carcinoma, usually Squamous cell carcinoma Pulmonary tuberculosis (without causing abscess) Rare infections, including – Actinomycosis , Nocardiasis , Fungal pneumonia

92. Differential diagnosis (Contd) In Lung abscess Fever, systemic complaints purulent sputum and WBC count >11x109/L more likely to be found Response to antibiotic therapy

93. Differential diagnosis…/ Radiologically Necrosis in a lung tumour Age more than 50 years No history suggestive of aspiration Lesions need not be situated in a typically dependent segment of the lung In CXR: an eccentric cavity with thick irregular walls

94. Differential diagnosis…/ Radiologically

95. Differential diagnosis…/ Radiologically Lung cancer and lung abscess may occur together, particularly in elderly patients necrotic tissue in a tumour may become infected as well as the tumour itself causing the stagnation of distal secretions with subsequent infection

96. Differential diagnosis…/ Radiologically Empyema Empyema is a purulent infection that in most cases is confined to the pleural space, although it can develop as a complication, or be a cause, of a lung abscess If an empyema contains an air-fluid level, then a broncho -pleural fistula is likely to be present Often difficult to distinguish radiographically between a localized empyema with a bronchopleural fistula and a lung abscess

97. Differential diagnosis…/ Radiologically Classically the empyema is seen on the lateral chest Xray as a ‘D-shaped’ opacity with the convexity projecting anteriorly from the posterior chest wall

98. Differential diagnosis…/ Radiologically Empyema

99. Differential diagnosis…/ Radiologically CT may be helpful in doubtful cases In abscess: wall is of varying thickness with an irregular intraluminal margin and exterior surfaces In empyema : wall is cavities tend to be smooth, separating the thickened pleural layers with compressed lung beneath the visceral layer

100. Differential diagnosis…/ Radiologically Infected bullae Infected bulla is parenchymal & Empyema is extra- parenchymal both entities can demonstrate air-fluid levels An infected bulla is pneumonia within a preexisting bullous cavity and does not result from tissue necrosis Patient with infected bulla is less ill than might be suggested by the chest radiograph

101. Differential diagnosis…/ Radiologically Infected bullae …. There may be little evidence of consolidation in surrounding lung when compared with an abscess The margin of the bulla can often be seen to have a thin, smooth wall on plain films or CT An earlier CXR may assist in making this diagnosis Infection within a bulla may cause its obliteration but this is rare

102. Differential diagnosis…/ Radiologically Lung abscess Empyema Infected bullae is a thick, irregular walled cavity with no associated lung compression lung usually is characterized by thin, smooth walls with compression of uninvolved lung usually is characterized by thin, smooth walls with compression of uninvolved lung minimal surrounding inflammation

103. Lung abscess Empyema Fever, systemic complaints Purulent infection ,confined to pleural space Purulent sputum Can developed as a complication, or be a cause, of a lung abscess WBC count >11x109/L If an empyema contains an air-fluid level, then a broncho -pleural fistula is likely to be present Response to antibiotic therapy Often difficult to distinguish radiographically between a localized empyema with a bronchopleural fistula and a lung abscess. In CT - wall is of varying thickness with an irregular itraluminal margin and exterior surface. Seen on the lateral Chest X-ray as a D- shaped opacity with the convexity projecting Anteriorly from the Posterior Chest wall. Differential diagnosis…/ Radiologically

104. Infected bullae Necrosis in a lung tumour Infected bulla is parenchymal & Empyema is extra- parenchymal - both entities can demonstrate air-fluid levels An infected bulla is pneumonia within a preexisting bullous cavity and does not result from tissue necrosis Patient with infected bulla is less ill than might be suggested by the chest radiograph There may be little evidence of consolidation in surrounding lung when compared with an abscess. The margin of the bulla can often be seen to have a thin, smooth wall on plain films or CT. An earlier CXR may assist in making this diagnosis. Infection within a bulla may cause its obliteration but this is rare Age more >50 years, No History suggestive of Aspiration. Lesion need not to be situated in typically dependent segment of lung. In CXR – Eccentric cavity with thick irregular walls. Differentialdiagnosis …/ Radiologically

105. Differential diagnosis…/ Radiologically Infection within a lung cyst Bronchogenic and other congenital foregut cysts may be impossible to differentiate from a lung abscess unless previous films are available for comparison

106. Differential diagnosis…/ Radiologically Similar difficulties may be posed by infection in a congenital sequestrated segment The diagnosis is made by the position of the lesion (usually lower lobe) and by retrograde aortography

107. Differential diagnosis…/ Radiologically Hiatus hernia Diagnosis is suggested by ‘double cardiac shadow’ on the P/A chest X-ray and confirmed on the lateral view by the typical appearance of a gastric air bubble behind the heart often with a fluid level Further diagnostic confirmation may be provided by a barium meal or upper GI endoscopy if there is doubt

108. Infection within a lung cyst Hiatus hernia Bronchogenic and other congenital foregut cysts may be impossible to differentiate from a lung abscess unless previous films are available for comparison. Diagnosis is suggested by ‘double cardiac shadow’ on the P/A chest X-ray The diagnosis is made by the position of the lesion (usually lower lobe) and by retrograde aortography . Confirmed on the lateral view by the typical appearance of a gastric air bubble behind the heart often with a fluid level Similar difficulties may be posed by infection in a congenital sequestrated segment. Further diagnostic confirmation may be provided by a barium meal or upper GI endoscopy if there is doubt.

109. A chest radiograph in a patient with a huge air-filled hiatal hernia, which appears as a mediastinal mass. Hiatal Hernia

110. Differential diagnosis…/ Radiologically Pulmonary haematoma A history of recent trauma to the chest suggests the diagnosis Sputum, if present, is not purulent Spontaneous dissolution of the haematoma usually occurs within a few weeks

111. Causes Of Cavitary Lesions In Lungs

112. Causes of Cavitary lesions in lungs Infections Bacterial Lung abscess [anaerobic & aerobic lung abscess] Infected pulmonary infarct Tuberculosis (actually a lung abscess) Infected bullae Empyema Actinomycosis

113. Causes of Cavitary lesions in lungs Fungal infection Coccidioidomycosis Histoplasmosis Blastomycosis Aspergillosis Cryptococcosis Parasitic Echinococcosis Amoebiasis

114. Causes of Cavitary lesions in lungs ( Contd ) Inflammatory Wegener’s granulomatosis Sarcoidosis Rheumatoid nodules Neoplastic (Cavitating malignancy) Bronchogenic carcinoma ( Squamous cell carcinoma) Metastatic carcinoma (Colorectal carcinoma, Renal cell carcinoma) Lymphoma (Hodgkin’s disease)

115. Complications

116. Complications Pleurisy Massive haemoptysis Spontaneous rupture into uninvolved lung segments Failure of abscess cavity to resolve Empyema - Rupture into pleural space causing empyema Bronchiectasis / Pleural fibrosis Trapped lung 30% of the time Results from a bronchopleural fistula

117. Complications ( contd ) Distant septic complications (< 10%) IncludesMetastatic brain infection/ Cerebral abscess Unrelenting sepsis Respiratory failure Amyloidosis (rare) – in chronic cases Bronchopleural fistula Pleural- cutaneous fistula

118. Treatment

119. Treatment Principles: Sputum is sent for C/S & broad-spectrum antibiotic should be started Postural drainage & chest physiotherapy Surgery Treatment of the cause if any

120. Treatment… Antimicrobials Currently the mainstay of therapy is antimicrobial therapy Antibiotics should be given according to the culture & sensitivity for prolonged period Commonly sputum is sent for C/S and a broad-spectrum antibiotic should be started

121. Treatment… Modifications to treatment may be made according to response or in light of culture and sensitivity (C/S) results If improves, continue as above If no response, antibiotic should be changed according to the C/S report

122. Treatment… The majority of patients are treated empirically Most lung abscess pathogens are sensitive to conventional antimicrobial therapy Majority of lung abscesses are related to aspiration and are caused by anaerobes About 90% of patients with anaerobic lung abscess responds to medical treatment

123. Treatment… Clindamycin associated with fewer treatment failure & a shorter time to symptom resolution than penicillin May be preferable to other agents. Dose is 600 mg IV every 6-8 hourly Switching to oral therapy at a dose of 300 mg every 6-8 hourly when the patient improves

124. Treatment… Antibiotic Regimen For Aspiration Pneumonia Clindamycin + fluoroquinolone Clindamycin + aminoglycosides Clindamycin + third/fourth generation cepalosporin Imipenem / meropenem  

125. Treatment… In hospitalized patients who have aspirated and developed a lung abscess Antibiotic therapy should include coverage against S aureus and enterobacter and pseudomonas species

126. Treatment… Pseudomonas aeruginosa infection is possible : prior antibiotic use, prolonged hospital course, or severe pneumonia If P. aeruginosa infection is suspected, dual anti- Pseudomonas therapy should be initiated with a Î’-lactam / aminoglycoside or a Î’-lactam / quinolone combination

127. Treatment… Antimicrobial options for common infecting bacteria Organism Antimicrobial options Staph. aureus Flucloxacillin , clindamycin Pseudomonas aeruginosa Ciprofloxacin, piperacillin-tazobactam , aztreonam , meropenem , aminoglycosides , ceftazidime / cefepime Enterobacter spp. Ciprofloxacin, meropenem , aminoglycosides

128. Treatments that may reduce chest exacerbations and/or improve lung function in CF

129. Treatment… Anaerobic lung infection Clindamycin shown to be superior over parenteral penicillin causes several anaerobes may produce B- lactamase & therefore develop penicillin resistance Although metronidazole is an effective drug against anaerobic bacteria , a failure rate of 50% has been reported

130. Treatment… Penicillin has a cure rate of 95%. It has activity against aerobic & microaerophilic streptococcus Metronidazole alone is not recommended as single-agent theapy with 43% failure rate

131. Treatment… Current recommendations are that Patients are usually treated until the pulmonary infiltrates have resolved or the residual lesion is small and stable

132. Treatment… Initially, antibiotics are given IV until the patient is afebrile & shows clinical improvement (4-8 days) Oral medications are then given, usually for a prolonged period Oral therapy can be as effective as parenteral therapy

133. Treatment… Duration of therapy Although the duration of Antimicrobial therapy is not well established most clinicians generally prescribe antibiotic therapy for a total of 4-8 weeks

134. Patients with poor response to a ntibiotic therapy bronchial obstruction with a foreign body or neoplasm infection with a resistant bacteria, mycobacteria, or fungi Large cavity size ( ie , > 6 cm in diameter) usually requires prolonged therapy

135. Response to therapy Patients with lung abscesses usually show clinical improvement with improvement of fever, within 3-4 days after initiating the antibiotic therapy Defervescence is expected in 7-10 days Persistent fever beyond this time indicates therapeutic failure / & these patients should undergo further diagnostic studies to determine the cause of failure

136. Treatment… Aspiration/drainage of pus If no response to medical therapy (in 1-10% cases), percutaneous aspiration under USG/CT guided may be required

137. Treatment… On rare occasions, pus from a large abscess may flood into the tracheobronchial tree so that the rigid bronchoscopy is probably safer as it allows adequate suctioning

138. Inpatient Care For the following reasons, inpatient care is advisable initially in patients with lung abscess Evaluation and management of patient's respiratory status Administration of intravenous antibiotics Drainage of the abscess or empyema as needed

139. Outpatient Care In patients who have small lung abscess who are not clinically ill who are reliable outpatient care may be considered after obtaining appropriate diagnostic studies such as sputum culture, blood culture etc. Following initial intravenous antibiotic therapy, the patient may be treated on an outpatient basis for completion of prolonged therapy, which is often required for cure

140. Surgical treatment Surgery is very rarely required for patients with uncomplicated lung abscesses Approx. 10% of lung abscess require surgical intervention

141. Surgical treatment… Patients who fail medical therapy Complications e.g. a. Massive haemoptysis Bronchopleural fistula Empyema 4.Suspected neoplasm Congenital lung malformation In the setting of fulminant infection Usual indications for surgery

142. Surgical treatment… The surgical procedure performed is either lobectomy or pneumonectomy Tube thoracostomy in the case of empyema and Lung resection(either lobectomy or pneumonectomy ) in the case of massive haemoptysis

143. Surgical treatment … Sometimes, surgery ( eg - lobectomy ) may be done The most frequent indication for thoracotomy and resection is the suspicion that the abscess is a cavitating tumour Lung resection is also occasionally necessary for massive and life-threatening haemoptysis

144. Surgical treatment … Drainage of an abscess is recommended when Sepsis persists 5 to 7 days after the initiation of antibiotic therapy Abscess larger than 4 cm Abscess increase in size while the patient is on medical therapy Rupture into pleural space causing empyema In a patient with coexisting empyema and lung abscess

145. Response to therapy In a study of 71 patients 13% of lung abscess cavities had disappeared in 2 weeks 44% in 4 weeks 59% in 6 weeks 70% within 3 months after treatment with appropriate antibiotics There is residual chest radiographic shadowing when extensive fibrosis has occurred

146. Chest physiotherapy

147. Chest physiotherapy encouragement of cough & mobilization of secretions are potentially useful intervention. Adequate drainage of the lung abscess is an important part of management. An air-fluid level implies the presence of a communication from the abscess cavity to the tracheobronchial tree.

148. Chest physiotherapy… Chest physiotherapy & postural drainage may be helpful in helping the patient to clear purulent material and postural drainage can be applied with the affected pulmonary segments uppermost Significant pulmonary haemorrhage may occur

149. Don't worry about what people say behind your back. They are the people who are finding faults in your life instead of fixing their own.

150. Prognosis

151. Prognosis Lung abscess was a devastating disease in the pre antibiotic era when one third of the patients died another one third recovered and the remainder developed debilitating illnesses such as recurrent abscesses, chronic empyema, bronchiectasis, or other consequences of chronic Pyogenic infections

152. Prognosis… The prognosis for lung abscess following antibiotic treatment is generally favorable Over 90% of lung abscesses are cured with medical management alone unless caused by bronchial obstruction secondary to carcinoma

153. Prognosis… Most patients with primary lung abscess improve with antibiotics with cure rates documented at 90-95% Mortality between 5 and 10% 2.4% in community-acquired lung abscess & 66.7% in hospital-acquired lung abscess

154. Prognosis… Recurrent aspiration serious co-morbidity Prolonged symptom complex before presentation Presence of thick-walled cavities cavity size (>6 cm) Development of empyema Advanced age Abscess associated with an obstructing lesion/ Neoplasm Prognostic factors associated with failure of medical therapy

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156. Prevention Prevention

157. Prevention Prevention of aspiration is important to minimize the risk of lung abscess Vomiting patients should be placed on their sides Improving oral hygiene and dental care in elderly and debilitated patients Positioning the supine patient at a 30° reclined angle minimizes the risk of aspiration Early intubation in patients who have diminished ability to protect the airway from massive aspiration (cough, gag reflexes), should be considered

158. Reference: Baum's Textbook of Pulmonary Diseases, 7 th Edition Crofton and Douglas's Respiratory Diseases, 5 th Edition Harrison's Principles of Internal Medicine, 18 th Edition Davidson's Principles and Practice of Medicine, 22rd Edition

159. THANK YOU !