Lung abscess is defined as necrosis of pulmonary tissue and formation of cavities containing necrotic debris or fluid, usually caused by microbial infection. It commonly results from aspiration of oropharyngeal contents colonized with anaerobic bacteria. Patients often present with nonspecific symptoms like fever, cough, sputum production, and weight loss. Physical exam may reveal consolidation and signs of any associated pleural effusions or pneumothoraces. Treatment involves prolonged antibiotic therapy, though surgery was historically used. Failure to treat lung abscess is associated with poor clinical outcomes.

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Lung Abscess
Lung Abscess
Presented by Dr. Deena Abde
Presented by Dr. Deena Abdel
l Hadi
Hadi
Directed by Dr. Abdul-Rahman Abu Rubb
Directed by Dr. Abdul-Rahman Abu Rubb

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Background
Background
:Definition
:Definition
Necrosis
Necrosis of the pulmonary tissue &
of the pulmonary tissue &formation of
formation of
cavities
cavities containing
containingnecrotic debris
necrotic debris or
orfluid
fluid
.caused by microbial infection
.caused by microbial infection
The formation of multiple small )> 2 cm(
The formation of multiple small )> 2 cm(
abscesses is occasionally referred to as
abscesses is occasionally referred to as
necrotizing pneumonia
necrotizing pneumonia or
or.lung gangrene
.lung gangrene

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Failure to recognize & treat lung abscess is associated
Failure to recognize & treat lung abscess is associated
.with poor clinical out-come
.with poor clinical out-come
Lung abscess was a devastating disease in the
Lung abscess was a devastating disease in thepre-
pre-
antibiotic era
antibiotic era, when 1/3 of the patients died, another
, when 1/3 of the patients died, another
1/3 recovered, & the remainder developed
1/3 recovered, & the remainder developed
debilitating illnesses
debilitating illnesses]i.e. recurrent abscesses,
]i.e. recurrent abscesses,
.]chronic empyema, bronchiectasis
.]chronic empyema, bronchiectasis

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

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Lung abscesses can be classified based on the
Lung abscesses can be classified based on the duration
duration
& the likely
& the likelyetiology
etiology
.
.
Acute abscesses
Acute abscesses are less than 4-6 wks old
are less than 4-6 wks old, whereas
, whereas
chronic abscesses
chronic abscesses .are of longer duration
.are of longer duration
Primary abscess
Primary abscess is
isinfectious
infectious in origin, caused by
in origin, caused by
aspiration or pneumonia
aspiration or pneumonia . in the healthy host
. in the healthy host

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Secondary Abscess
Secondary Abscess: is caused by
: is caused by
.)Pre-existing condition )obstruction -
.)Pre-existing condition )obstruction -
.Spread from an extra-pulmonary site -
.Spread from an extra-pulmonary site -
.Bronchiectasis -
.Bronchiectasis -
.An immuno-compromised state -
.An immuno-compromised state -
Lung abscesses can be further characterized by the
Lung abscesses can be further characterized by the
responsible pathogen, such as
responsible pathogen, such asStaphylococcus
Staphylococcus lung
lung
abscess
abscess &
& anaerobic
anaerobic or
orAspergillus
Aspergillus . lung abscess
. lung abscess

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Pathophysiology
Pathophysiology
Lung abscess arises as a
Lung abscess arises as acomplication of aspiration
complication of aspiration
.pneumonia caused by mouth anaerobes
.pneumonia caused by mouth anaerobes
A bacterial inoculums from the
A bacterial inoculums from the gingival crevice
gingival crevice
reaches the lower airways
reaches the lower airways, & infection is initiated
, & infection is initiated
coz the bacteria aren‘t cleared by the patient‘s host
coz the bacteria aren‘t cleared by the patient‘s host
.defense mechanism
.defense mechanism

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Abscesses generally develop in the
Abscesses generally develop in theright lung
right lung and
and
involve the
involve theposterior segment of the right upper
posterior segment of the right upper
lobe
lobe , the
, thesuperior segment of the lower lobe
superior segment of the lower lobe, or
, or
both. This is
both. This isdue to gravitation of the infectious
due to gravitation of the infectious
material from the oropharynx into these dependent
material from the oropharynx into these dependent
.areas
.areas

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Initially, the aspirated material settles in the distal
Initially, the aspirated material settles in the distal
bronchial system and develops into a localized
bronchial system and develops into a localized
pneumonitis. Within 24-48 hours, a large area of
pneumonitis. Within 24-48 hours, a large area of
inflammation results, consisting of exudate, blood,
inflammation results, consisting of exudate, blood,
and necrotic lung tissue. The abscess frequently
and necrotic lung tissue. The abscess frequently
.connects with a bronchus and partially empties
.connects with a bronchus and partially empties

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Other mechanisms for lung abscess formation
Other mechanisms for lung abscess formation
: include
: include
:Septic emboli to the lung ,caused by
:Septic emboli to the lung ,caused by
)1
)1.Bacteremia
.Bacteremia
)2
)2 .Tricuspid valve endocarditis
.Tricuspid valve endocarditis

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Microbiology
Microbiology
Anaerobes are recovered in up to 89% of the patients,
Anaerobes are recovered in up to 89% of the patients,
46%
46% of patients with lung abscess had only a
of patients with lung abscess had only a
mixture of
mixture ofanaerobes
anaerobes isolated from sputum
isolated from sputum
cultures while
cultures while43%
43% of patients had a mixture of
of patients had a mixture of
anaerobes
anaerobes &
&.aerobes
.aerobes
The most common anaerobes are
The most common anaerobes arePeptosretococcus,
Peptosretococcus,
Bacteroids
Bacteroids ,
,Fusobacterium
Fusobacterium species &
species &
.Microaerophilic streptococcus
.Microaerophilic streptococcus

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Other organisms that may infrequently cause
Other organisms that may infrequently cause
lung abscess include
lung abscess includeStaphylococcus aureus,
Staphylococcus aureus,
Streptococcus pyogens, Streptococcus
Streptococcus pyogens, Streptococcus
pneumoniae
pneumoniae)rarely(,
)rarely(, Klebsiella pneumoniae,
Klebsiella pneumoniae,
Hemophilus influenza, Actinomyces species,
Hemophilus influenza, Actinomyces species,
.Nocardia species, & Gm negative bacilli
.Nocardia species, & Gm negative bacilli

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. Non-bacterial pathogens may also cause lung abscesses
. Non-bacterial pathogens may also cause lung abscesses
:Theses micro-organisms include
:Theses micro-organisms include
)1
)1
Parasites
Parasites ]
]Paragonimus , Entamoeba
Paragonimus , Entamoeba
.]
.]
)2
)2
Fungi
Fungi]
] Aspergillus , Cryptococcus ,
Aspergillus , Cryptococcus ,
Histoplasma , Blastomyces , Coccidioides
Histoplasma , Blastomyces , Coccidioides
.]
.]
)3
)3
.Mycobacterium
.Mycobacterium

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History
History
:Anaerobic infection
:Anaerobic infection
Patients often present with indolent symptoms that )1
Patients often present with indolent symptoms that )1
.evolve over a period of weeks to months
.evolve over a period of weeks to months
The usual symptoms are )2
The usual symptoms are )2 fever
fever ,
,cough with sputum
cough with sputum
production
production ,
,night sweats
night sweats ,
,anorexia
anorexia &
&weight loss
weight loss
.
.
The expectorated )3
The expectorated )3 sputum
sputum characteristically is
characteristically isfoul
foul
.smelling & bad tasting
.smelling & bad tasting
Patients may develop )4
Patients may develop )4.hemoptysis or pleurisy
.hemoptysis or pleurisy

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:Other bacterial pathogens
:Other bacterial pathogens
These patients generally present with conditions )1
These patients generally present with conditions )1
that are more emergent in nature & are usually
that are more emergent in nature & are usually
.treated while they have bacterial pneumonia
.treated while they have bacterial pneumonia
)2
)2Cavitation occurs subsequently as parenchymal
Cavitation occurs subsequently as parenchymal
.necrosis ensues
.necrosis ensues
Abscesses from fungi, )3
Abscesses from fungi, )3 Nocardia
Nocardia& Mycobacteria
& Mycobacteria
tend to have an indolent course & gradually
tend to have an indolent course & gradually
.progressive symptoms
.progressive symptoms

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Physical
Physical
Patients may have
Patients may havelow-grade fever in anaerobic
low-grade fever in anaerobic
infections
infections &
&.temperature < 38.5 C in other infections
.temperature < 38.5 C in other infections
Generally,
Generally,evidence of gingival disease is present
evidence of gingival disease is present
.
.
Clinical findings of consolidation may be present
Clinical findings of consolidation may be present :
:
]decreased breath sounds, dullness to percussion,
]decreased breath sounds, dullness to percussion,
.]bronchial breath sounds, course inspiratory crackles
.]bronchial breath sounds, course inspiratory crackles

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Evidence of pleural friction rub signs of associated
Evidence of pleural friction rub signs of associated
pleural effusion, empyema & pyo-pneumothorax may
pleural effusion, empyema & pyo-pneumothorax may
be present. Signs include
be present. Signs include
:
:
dullness to percussion, contralateral mediastinal shifting]
dullness to percussion, contralateral mediastinal shifting]
.]& absent breath sounds over the effusion
.]& absent breath sounds over the effusion
.Digital clubbing may develop rapidly
.Digital clubbing may develop rapidly

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Causes
Causes
The bacterial infection may reach the lungs in
The bacterial infection may reach the lungs in
several ways .that most common is
several ways .that most common is
.aspiration of oro-pharyngeal contents
.aspiration of oro-pharyngeal contents

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Factors contributing to lung abscess
Factors contributing to lung abscess
Oral cavity disease
Oral cavity disease
Periodontal disease
Periodontal disease
Gingivitis
Gingivitis
Altered consciousness] inability to
Altered consciousness] inability to protect their
protect their
]airways coz of an absent gag reflex
]airways coz of an absent gag reflex
Alcoholism
Alcoholism
Coma
Coma
Drug abuse
Drug abuse
Anesthesia
Anesthesia
Seizures
Seizures

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Immunocompromised host
Immunocompromised host
Steroid chemotherapy
Steroid chemotherapy
Malnutrition
Malnutrition
Multiple trauma
Multiple trauma
Esophageal disease
Esophageal disease
Achalasia
Achalasia
Reflux disease
Reflux disease
Depressed cough and gag reflex
Depressed cough and gag reflex
Esophageal obstruction
Esophageal obstruction

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Bronchial obstruction
Bronchial obstruction
Tumor
Tumor
Foreign body
Foreign body
Stricture
Stricture
Generalized sepsis
Generalized sepsis

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patients with 1ry lung disorders
patients with 1ry lung disorders
.Septic emboli from tricuspid endocarditis
.Septic emboli from tricuspid endocarditis
.Vasculitic disorders
.Vasculitic disorders
.Cavitating lung malignancies
.Cavitating lung malignancies
.Pulmonary cystic diseases
.Pulmonary cystic diseases

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The following infectious etiologies of pneumonia
The following infectious etiologies of pneumonia
infrequently progress to parenchymal necrosis & lung
infrequently progress to parenchymal necrosis & lung
:abscess formation
:abscess formation
-
-
.Pseudomonas aerugenosa
.Pseudomonas aerugenosa
.Klebsiella pneumoniae -
.Klebsiella pneumoniae -
Staph. aureus -
Staph. aureus -
.))may result in multiple abscesses
.))may result in multiple abscesses
.Strept. Pneumonia -
.Strept. Pneumonia -
.Nocardia species -
.Nocardia species -
.Fungal species -
.Fungal species -

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An abscess may occur
An abscess may occur2ry to bronchial
2ry to bronchial
carcinoma
carcinoma , the
, thebronchial obstruction causes
bronchial obstruction causes
post-obstructive pneumonia which may lead
post-obstructive pneumonia which may lead
to abscess formation
to abscess formation
.
.

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Differential Diagnosis
Differential Diagnosis
Alcoholism )1
Alcoholism )1
Pleuro-pulmonary )2
Pleuro-pulmonary )2
. Empyema
. Empyema
.Hydatid Cysts )3
.Hydatid Cysts )3
.Lung Cancer )4
.Lung Cancer )4
.Mycobacterium )5
.Mycobacterium )5
Pneumococcal )6
Pneumococcal )6
. infections
. infections
Pneumocystis Carnii )7
Pneumocystis Carnii )7
.pneumonia
.pneumonia
.Aspiration pneumonia )8
.Aspiration pneumonia )8
.Bacterial pneumonia )9
.Bacterial pneumonia )9
.Fungal pneumonia )10
.Fungal pneumonia )10
.Pulmonary embolism )11
.Pulmonary embolism )11
.Sarcoidosis )12
.Sarcoidosis )12
.T.B )13
.T.B )13

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Lab Studies
Lab Studies
-
-
CBC
CBC
-
-
Sputum
Sputum for
forgram stain
gram stain ,
,culture & sensitivity
culture & sensitivity
.
.
If T.B. is suspected, -
If T.B. is suspected, -
acid fast bacilli stain
acid fast bacilli stain &
&
mycobacterial culture
mycobacterial culture. is requested
. is requested
-
-
Blood culture
Blood culture may be helpful in establishing the
may be helpful in establishing the
. etiology
. etiology
Obtain -
Obtain -
sputum
sputum for
forova
ova &
& parasite
parasite whenever a
whenever a
. parasitic cause for lung abscess is suspected
. parasitic cause for lung abscess is suspected

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Histopathology
Histopathology
A thick-walled lung abscess
A thick-walled lung abscess

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Histology of lung abscess
Histology of lung abscess shows dense inflammatory
shows dense inflammatory
reaction
reaction((low power
((low power

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Histology of lung abscess shows dense inflammatory
Histology of lung abscess shows dense inflammatory
reaction
reaction((high power
((high power

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Imaging Studies
Imaging Studies
:CXR
:CXR
-
-
.Irregularly sharp cavity with an air-fluid level inside
.Irregularly sharp cavity with an air-fluid level inside
Lung abscess as a result of aspiration most frequently -
Lung abscess as a result of aspiration most frequently -
occur in the posterior segments of the upper lobes or
occur in the posterior segments of the upper lobes or
.the superior segments of the lower lobe
.the superior segments of the lower lobe

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The wall thickness of a lung abscess -
The wall thickness of a lung abscess -
progresses from thick to thin and from ill-
progresses from thick to thin and from ill-
defined to well-circumscribed as the
defined to well-circumscribed as the
.surrounding lung infection resolves
.surrounding lung infection resolves
-
-
The cavity wall can be smooth or ragged but
The cavity wall can be smooth or ragged but
is less commonly nodular, which raises the
is less commonly nodular, which raises the
.possibility of cavitating carcinoma
.possibility of cavitating carcinoma

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

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Pneumococcal pneumonia
Pneumococcal pneumonia
complicated by lung necrosis &
complicated by lung necrosis &
abscess formation
abscess formation

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A lateral CXR shows air fluid level
A lateral CXR shows air fluid level
((characteristic of lung abscess
((characteristic of lung abscess

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A 54 yr old pt. developed cough with foul-
A 54 yr old pt. developed cough with foul-
smelling sputum production. A CXR
smelling sputum production. A CXR
.shows lung abscess in the left lower lobes
.shows lung abscess in the left lower lobes

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A 42 y.o. man developed fever & production of foul-
A 42 y.o. man developed fever & production of foul-
smelling sputum. He had a H/O heavy alcohol use &
smelling sputum. He had a H/O heavy alcohol use &
poor dentition, CXR shows lung abscess in the post
poor dentition, CXR shows lung abscess in the post
.segment of the Rt. up. lobe
.segment of the Rt. up. lobe

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

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-
:CT scan
:CT scan
Better in lung anatomy visualization to identify -
Better in lung anatomy visualization to identify -
.empyema from lung infarction
.empyema from lung infarction
An abscess is rounded radio-lucent lesion with a think -
An abscess is rounded radio-lucent lesion with a think -
.wall & ill-defined irregular margins
.wall & ill-defined irregular margins

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A 42 yr old man developed fever & production of foul-
A 42 yr old man developed fever & production of foul-
smelling sputum. He had a H/O heavy alcohol abuse & poor
smelling sputum. He had a H/O heavy alcohol abuse & poor
dentition, CXR shows lung abscess in the post. Segment of
dentition, CXR shows lung abscess in the post. Segment of
the Rt. Up. Lobe. CT scan shows a thin-walled cavity with
the Rt. Up. Lobe. CT scan shows a thin-walled cavity with
.surrounding consolidation
.surrounding consolidation

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Procedures
Procedures
Trans-tracheal aspirate or trans-thoracic needle -
Trans-tracheal aspirate or trans-thoracic needle -
aspiration may provide microbiologic diagnosis,
aspiration may provide microbiologic diagnosis,
obtaining pleural fluid and blood cultures in patients
obtaining pleural fluid and blood cultures in patients
.with lung abscess is easier
.with lung abscess is easier
Flexible fiberoptic bronchoscopy is performed to -
Flexible fiberoptic bronchoscopy is performed to -
exclude bronchogenic carcinoma whenever bronchial
exclude bronchogenic carcinoma whenever bronchial
obstruction is suspected
obstruction is suspected
.
.

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Medical Care
Medical Care
:Antibiotic therapy
:Antibiotic therapy
Anaerobic lung infection = -
Anaerobic lung infection = -
Clindamycin
Clindamycin ]shown to be
]shown to be
superior over parenteral penicillin coz several
superior over parenteral penicillin coz several
anaerobes may produce B-lactamase & therefore
anaerobes may produce B-lactamase & therefore
.]develop penicillin resistance
.]develop penicillin resistance
Although -
Although -
metronidazole
metronidazole is an effective drug against
is an effective drug against
anaerobic bacteria, a failure rate of 50% has been
anaerobic bacteria, a failure rate of 50% has been
.reported
.reported

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In hospitalized patients who have aspirated and -
In hospitalized patients who have aspirated and -
developed a lung abscess, antibiotic therapy should
developed a lung abscess, antibiotic therapy should
include coverage against
include coverage againstS aureus
S aureus and
andEnterobacter
Enterobacter
and
andPseudomonas
Pseudomonas .species
.species
-
-
Cefoxitin
Cefoxitin is a second-generation cephalosporin that
is a second-generation cephalosporin that
has gram-positive, gram-negative, and anaerobic
has gram-positive, gram-negative, and anaerobic
coverage. This agent may be used when a
coverage. This agent may be used when a
polymicrobial infection is suspected as cause of
polymicrobial infection is suspected as cause of
.lung abscess
.lung abscess

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:Duration of therapy
:Duration of therapy
Most clinicians prescribe antibiotic therapy generally -
Most clinicians prescribe antibiotic therapy generally -
for
for.4-6 weeks
.4-6 weeks
Current recommendations are that antibiotic -
Current recommendations are that antibiotic -
treatment should be continued until the
treatment should be continued until thechest
chest
radiograph has shown either the resolution of lung
radiograph has shown either the resolution of lung
.abscess or the presence of a small stable lesion
.abscess or the presence of a small stable lesion

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:Response to therapy
:Response to therapy
-
-
Patients show clinical improvement, with
Patients show clinical improvement, with
improvement of fever, within 3-4 days after
improvement of fever, within 3-4 days after
.initiating the antibiotic therapy
.initiating the antibiotic therapy
Patients with poor response to antibiotic therapy -
Patients with poor response to antibiotic therapy -
include bronchial obstruction with a foreign body or
include bronchial obstruction with a foreign body or
neoplasm or infection with a resistant bacteria,
neoplasm or infection with a resistant bacteria,
.Mycobacteria, or fungi
.Mycobacteria, or fungi

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Surgical Care
Surgical Care
Surgery is
Surgery isvery rarely required
very rarely required for patients with
for patients with
uncomplicated lung abscesses. The usual indications
uncomplicated lung abscesses. The usual indications
for surgery are
for surgery arefailure to respond to medical
failure to respond to medical
management, suspected neoplasm, or congenital
management, suspected neoplasm, or congenital
lung malformation.
lung malformation. The surgical procedure
The surgical procedure
.performed is either lobectomy or pneumonectomy
.performed is either lobectomy or pneumonectomy

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Complications
Complications
1
1
.Rupture into pleural space causing empyema )
.Rupture into pleural space causing empyema )
.Pleural fibrosis )2
.Pleural fibrosis )2
.Trapped lung )3
.Trapped lung )3
.Respiratory failure )4
.Respiratory failure )4
.Bronchopleural fistula )5
.Bronchopleural fistula )5
.Pleural cutaneous fistula)6
.Pleural cutaneous fistula)6
In a patient with coexisting empyema and lung abscess,
In a patient with coexisting empyema and lung abscess,
draining the empyema while continuing prolonged
draining the empyema while continuing prolonged
.antibiotic therapy is often necessary
.antibiotic therapy is often necessary

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

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The End
The End
Thank You
Thank You