Lung abscess

Question 1

Local suppurative process that causes necrosis of lung tissue, caused by a variety of bacteria

Answer 1

Lung abscess

Question 2

List 6 causes of lung abscess

Answer 2

o Aspiration of infective material: Most frequent cause; first results in pneumonia then
progresses to lung abscess. Occurs in patients with suppressed cough reflexes (e.g. acute
alcohol intoxication, seizure), severe dysphagia (e.g. neurologic deficits), protracted vomiting, poor dental hygiene
o Post-pneumonia: Especially in post-transplant or immunosuppressed patients. Organisms are usuallyS.aureus, K.pneumoniae, pneumococcus
o Septic embolism: Infected emboli from thrombophlebitis or infective endocarditis
o Post-obstructive pneumonia:e.g. obstruction from lung tumours
o Miscellaneous: e.g. direct extension of suppurative infections from adjacent structures e.g. oesophagus, traumatic penetration of lungs, haematogenous seeding of lungs
o Cryptogenic

Question 3

List clinical features of lung abscess

Answer 3

Clinical features: Similar to bronchiectasis – productive purulent cough, fever, chest pain and weight
loss. Need to exclude underlying carcinoma (10-15% of cases) in older patients

Question 4

List complications of lung abscess

Answer 4

Complications: Extension into pleural cavity, haemorrhage, production of septic emboli to brain or
meninges, secondary amyloidosis (type AA)

Question 5

List the Gross appearance of lung abscess

Answer 5

Gross: Cavity. Single (more often in aspiration; right-sided) or multiple (more often due to
pneumonia or bronchiectasis in which they are basal and diffusely scattered; or any region of the
lungs if due to septic emboli)

Question 6

List the micro appearance of Lung abscess

Answer 6

• Micro: Suppurative destruction of lung parenchyma within the central area of cavitation; may have a
  surrounding fibrous wall in chronic cases

Question 7

If the several abscesses with irregular, rough-surfaced walls within areas of tan consolidation are large enough, the contain what?

Answer 7

large enough, abscesses contain liquefied necrotic material and purulent exudate that often results in an air-fluid level on chest radiograph or CT scan.