Lung abscess is a localized area of lung parenchyma destruction greater than 2 cm in diameter caused by pyogenic infection. It is usually the result of aspiration of oropharyngeal or gastric contents but can also develop from necrotizing pneumonia, bronchial obstruction, or hematogenous spread. Common pathogens include anaerobic bacteria such as Prevotella species and aerobic bacteria like Staphylococcus aureus. Symptoms, imaging, and microbiological testing are required to diagnose lung abscess.

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!’

5. 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).

6. 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.

7. 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.

8. 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

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

10. 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)

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

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

13. 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
virulentanaerobicagent

14. Classification…

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

16. 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

17. 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)

18. 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.

19. 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

20. Classification…
Multiple lung abscess? Staphyloccal

21. Classification…
Multiple lung
abscess?
staphyloccal

22. 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

23. 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.

24. 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

25. 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

26. 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)

27. কখন বুঝবব একটি দেশ ও সমাজ নষ্ট হবে দেবে,
যখন দেখবব েরিদ্রিা ধৈযযহািা হবে দেবে, ৈনীিা
কৃ পন হবে দেবে, মুখযিা মবে ববস আবে,
জ্ঞানীিা পারিবে যাবে এবং শাসকিা রমথ্যা কথ্া
বিবে।
হযিত আিী (িাাঃ)

28. বস্তুত রনন্দা না থ্ারকবি পৃরথ্বীবত
জীববনি দেৌিব রক থ্ারকত? একটা
ভাি কাবজ হাত রেিাম, তাহাি রনন্দা
দকহ কবি না, দস ভাি কাবজি োম
কী। একটা ভাি রকেু রিরখিাম, তাহাি
রনন্দুক দকহ নাই, ভাি গ্রবহহি পবে
এমন মমযারিক আেি আি কী হইবত
পাবি!

29. CAUSES OF LUNG ABSCESS

30. Causes of Lung abscess (A) Aspiration
A) 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

31. 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

32. 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

33. 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

34. 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

35. 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

36. 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

37. 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

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

39. RISK FACTORS FOR GRAM NEGATIVE
COLONIZATION
1. Malnutrition
2. Severe illness
3. Coma
4. Intubation
5. Diabetes
6. Prior surgery
7. Lung disease
8. Renal failure
9. Prior antibiotic use
10. Hypotension
11. Cigarette smoking
12. Prolonged hospitalization

42. Pathology

43. 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.

44. 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.

45. 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).

46. 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.

48. Organisms Commonly Isolated

49. 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.

50. 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.

51. 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

52. A thick-walled lung abscess

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

55. Things To Remember
Do not speak about your money in front of a poor person.
Do not speak about your health in front of a sick person.
Do not speak about your power in front of a weak person.
Do not speak about your happiness in front of a sad person.
Do not speak about your freedom in front of a prisoner.
Do not speak about your children in front of an infertile person.
Do not speak about your mother and father in front of an orphan.
Because their wounds cannot bear more...

56. Symptoms/ Signs

57. 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

58. 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. aureus or K. pneumoniae)

59. 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

60. 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

61. 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

62. 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

63. 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

64. 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

66. INVESTIGATIONS

67. 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

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

70. IMAGING STUDIES

71. 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

72. 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.

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

74. Abscess cavities/multilocular

75. 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

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

82. 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

83. 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

84. 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

85. 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

86. 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

87. 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

88. 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

89. 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

90. 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

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

92. 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

95. Lung abscess

96. Lung Abscess

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

99. 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

100. 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

101. 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

102. 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

103. 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.

104. 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)

105. 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)

107. DIFFERENTIAL DIAGNOSIS

108. 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

109. 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

110. 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

111. Differential diagnosis…/Radiologically

112. 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

113. 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

114. 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

115. Differential diagnosis…/Radiologically
Empyema

116. 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

117. 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

118. 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

119. 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

120. 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

121. 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…/Rad
iologically

122. 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

123. 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

124. 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

125. 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.

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

127. 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

129. Causes Of Cavitary Lesions In Lungs

130. 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

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

132. 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)

134. Complications

135. 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

136. 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

138. Treatment

139. 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

140. 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

141. 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

142. 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

143. 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

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

145. 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

146. 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

147. 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

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

149. 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

150. 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

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

152. 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

153. 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

154. Patients with poor response to antibiotic 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

155. 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

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

157. 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

158. 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

159. 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

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

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

162. 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

163. 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

164. 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

165. 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

167. CHEST PHYSIOTHERAPY

168. 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.

169. 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

170. 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.

171. PROGNOSIS

172. 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

173. 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

174. 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

175. 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

176. Don’t feel bad if people
only remember you
when they need you.
Feel privileged that you
are like a candle that
comes to their mind
when they’re in
darkness.

177. Prevention
Prevention

178. 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

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

180. THANK
YOU !