Lung abscess

Question 1

What is it?

Answer 1

A lung abscess is a well-circumscribed infection within the lung parenchyma.

Question 2

Pathophysiology

Answer 2

most commonly forms secondary to aspiration pneumonia
poor dental hygiene, previous stroke and reduced consciousness are some of the risk factors for this
other potential causes include:
haematogenous spread e.g. secondary to infective endocarditis
direct extension e.g. from an empyema
bronchial obstruction e.g. secondary from a lung tumour
typically polymicrobial
monomicrobial causes include:
Staphylococcus aureus
Klebsiella pneumonia
Pseudomonas aeruginosa

Question 3

Features

Answer 3

similar features to pneumonia but generally runs a more subacute presentation
symptoms may develop over weeks
systemic features such as night sweats and weight loss may be seen
fever
productive cough
often foul-smelling sputum
haemoptysis in a minority of patients
chest pain
dyspnoea
signs
dull percussion and bronchial breathing
clubbing may be seen

Question 4

Investigation

Answer 4

chest x-ray
fluid-filled space within an area of consolidation
an air-fluid level is typically seen
sputum and blood cultures should be obtained

Question 5

Management

Answer 5

intravenous antibiotics
if not resolving percutaneous drainage may be required and in very rare cases surgical resection