Prepared & presented by: Dr :WADIE MADI
Tripoli Medical Centre.
Definition of Lung Abscess is:
-Necrosis of the pulmonary tissue & formation of cavities
containing necrotic debris or fluid caused by microbial
-The formation of multiple small (< 2 cm) abscesses is
occasionally referred to as necrotizing pneumonia or
- It manifests radiographically as a cavity with an air – fluid
Epidemiology: IN U.S.A
Frequency: the frequency of lung abscess in the
general population not known.(MEDSCAPE.COM.USA
Mortality & morbidity : most patients with primary lung
abscess improve with antibiotics , with cure rates
documented at 90-95%.(MEDSCAPE.COM.USA).
sex: male< female Age: lung abscess likely occur more
commonly in elderly patients bcz increase incidence of
In U.K(affect all age groups slight more in young adults
(P.DR-ANTHONY J FREW ,MD SOUTHAMPTON.UK)
Duration of symptoms prior to diagnosis;
Acute < 1 month
Chronic > 1 month
Primary lung abscess or Secondary lung abscess;
Primary lung abscess:
used when abscess develops in
individuals prone to aspiration or in
general good health
60-80% of lung abscess is primary
(50% of these associated with putrid
Secondary lung abscess:
obstructive airway neoplasm as a
complication of intrathoracic surgery or
systemic condition/treatment that
compromises host immune defense
Putrid lung abscess (foul odor of expectorated sputum)
o mouth flora anaerobes :Pepto strepto,Fuso bacterium nucleatum,
also Staph aureus, . Strepto pyogenes, Pseudomonas aeruginosa,
Klebsiella pneumoniae , Strepto pneumoniae
• gram-negative bacilli, such as E. coli , Homophiles influenza type B
• M. tuberculosis, (TUBERCULOUS LUNG ABSCESS) ,M. kansasii,)
• Aspergillus spp., Histoplasma capsulatum, Pneumocystis carinii,
• Entamoeba histolytica, Paragonimus westermani,
Wegener's granulomatosis, rheumatoid lung nodule
Bullae, blebs,cystic fibrosis ,bronchiectasis (usually thin-walled)
Primary lung cancer, metastatic carcinoma, lymphoma
Infective endocarditis due to S. aureus, Jugular venous septic phlebitis due
to Fusobacterium necrophorum (Lemierre syndrome)
Due to bland embolus (may be secondarily infected in <5%)
Most occur as a complication of aspiration pneumonia ,
due to anaerobic bacteria that are normal oral flora.
studies of patients with known time of aspiration suggest
that tissue necrosis with lung abscess formation takes at
least 1 week and up to 2 weeks to develop.
Aspirated bacteria are carried by gravity to dependent
portions of the lung.
Due to bronchus/carina anatomy, occur most frequently in
posterior segment of RtUL then posterior segment of LtUL
and then the superior segments of RtUL/LtLL.
:Risk Factors for lung abscess
Predisposition to aspiration
stroke, IV drug abuser , general anesthesia, dysphasia, respiratory
muscle dysfunction, tooth extractiont ,seizers,alcoholics .
45% of health adults aspirate during sleep(1ml of saliva with > 109
Poor dentition with gingivitis
-Neoplasm, Foreign bodies, extrinsic compression (enlarged lymph
- Steroid ,chemotherapy
-Malnutrition , HIV ,AIDS,DM
- Multiple trauma
-Depressed cough and gag reflex
secondary infection from bland pulmonary infarction/PE,
septic emboli from Tri V endocarditis
septic phlebitis of the neck (Fusobacterium) with embolic
infection in the lung may complicate oropharyngeal infection
Symptoms include : fever, night sweating, cough and Pleuritic
chest pain, cough is often non productive at first then
produce mucoid or mucopurulent expectorate from bronchial
inflammation close to the abscess area and sometimes there is
Weigh loss,, anaemia, and clubbing or pulmonary osteo
arthropathy, hymptosis in 1/3 of cases,
The onset may be abrupt or gradual.
Patients may have low-grade fever in anaerobic infections &
temperature > 38.5 C in other infections.
Clinical findings of consolidation may be present: [decreased
breath sounds, dullness in percussion, bronchial breath sounds,
course inspiratory crackles].
Evidence of pleural friction rub signs of associated pleural
effusion, empyema & pyo-pneumothorax may be present. Signs
include :[dullness to percussion, contralateral mediastinal shifting
& absent breath sounds over the effusion].
Digital clubbing may develop rapidly.
Amebic lung abscess
Patients who develop an amebic lung abscess often have symptoms
associated with a liver abscess.
These may include right upper quadrant pain and fever.
After perforation of the liver abscess into the lung, the patient may
develop a cough and expectorate a chocolate–like sputum that has
Sputum for gram stain, culture & sensitivity
If tuberculosis is suspected, ZeilNelsen and mycobacterial culture is
e.g CBC may show leukocytosis, blood glucose , LFT , RFT, U/E/C.
Obtain sputum for ova if parasitic is suspected
- Chest films may also reveal associated primary lesions,
e.g., a bronchogenic carcinoma.
- Malignant abcess shows eccentric cavitations with thick rough
- Irregularly sharp cavity with an air-fluid level inside.
- Lung abscess as a result of aspiration most frequently occur in
posterior segments of the upper lobes or superior segments
of lower lobes.
PA and lateral chest
radiographs 3 weeks later show
decreased size of lung abscess
and development of cavitation
with fluid level . The patient was
a 43-year-old woman with lung
abscess secondary to
complicated by lung necrosis
and abscess formation.
A lateral chest radiograph shows
air-fluid level characteristic of
A 54-year-old patient developed cough with foul-smelling sputum
production. A chest radiograph shows lung abscess in the left
lower lobe, superior segment.
- Better in lung anatomy visualization to identify empyema from lung
- An abscess is rounded radio-lucent lesion with a think wall & ill-
defined irregular margins.
scan demonstrates large
focal area of decreased
attenuation with rim
characteristic of lung
Because empyema with an air-fluid level could be mistaken for parenchymal
abscess, a CT scan may be used to differentiate this process from lung abscess
is performed to
Blood culture &
with quantitative cultures
Treatment of lung abscess is guided by the available microbiology and knowledge
of the underlying or associated conditions.
No treatment recommendations have been issued by major societies specifically
for lung abscess;
Clindamycin Is T.O.C [shown to be superior over parenteral penicillin coz
several anaerobes may produce B-lactamase therefore develop penicillin
Metronidazole is an effective drug against anaerobic bacteria, a failure rate of
50% has been reported.
May combine both Metronidazole & Penicillin
Other options: carbopenems, quionlones with good anaerobic activity
Anaerobic lung infection
In hospitalized patients who have aspirated and developed a lung abscess
antibiotic therapy should include coverage against S aureus and
Enterobacter and Pseudomonas species.
Duration of therapy
Although the duration of therapy is not well established,
most clinicians generally prescribe antibiotic therapy for 4-6 weeks.
Expert opinion suggests that antibiotic treatment should be continued until
the chest radiograph has shown either the resolution of lung abscess or
presence of a small stable lesion.
The risk of relapse exists with a shorter antibiotic regimen.
Response to therapy
Clinical improvement, decrease fever, within 3-4 days after initiating ABX
Defervescence is expected in 7-10 days.
Persistent fever beyond this time indicates therapeutic failure, and these
patients should undergo further diagnostic studies to determine the cause
Causes of delayed response to antibiotics
Large cavity size ( > 6 cm in diameter) usually requires prolonged therapy..
The infection of a preexisting sequestration, cyst, or bulla
bronchial obstruction with a foreign body
Complications of lung abscess
Rupture into pleural space causing Empyema
Pleural cutaneous fistula(T.B)
In a patient with coexisting empyema and lung abscess,
Draining the empyema while continuing prolonged
antibiotic therapy is often necessary.
Surgery is rarely required for patients with uncomplicated lung
The usual indications for surgery are
-- failure to respond to medical management,
-- suspected neoplasm, or
-- congenital lung malformation.
The surgical procedure performed is neither lobectomy or
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