Editing Lung abscess


Necrosis of the pulmonary parenchyma caused by microbial infection

== Aetiology ==

* Mostly a complication of aspiration pneumonia

== Pathophysiology ==

* Most common organisms - Peptostreptococcus, Prevotella, Bacteroides, Fusobacterium
** Others Staph aureus, Klebsiella pneumoniae, Strep pyogenes, Burkholderia pseudomallei, H influenzae type B, Legionella, Nocardia, Actinomyces
** Immunocompromised - look for Pseudomonas aeruginosa, other aerobic GNB, Nocardia, fungi (Aspergillus, Cryptococcus)
* Typically occurs in a segment of lung that that is dependent in the recumbent position 
** Superior segment of a lower lobe or a posterior segment of the upper lobes

== Presentation ==

* Usually indolent symptoms over weeks to months
* Fever, cough, sputum production
* Chronic systemic disease
* If the cavity spontaneously ruptures into the pleural cavity, treat for empyema or bronchopleural fistula, and lobectomy will usually be required (mortality 1-5%)

== Imaging ==

* CXR - infiltrates with a cavity
* CT indicated if suspected - helps to distinguish between a parenchymal lesion and a pleural collection

== Treatment ==

* Antibiotics
** Empirical combination
** Usually beta lactam or carbapenem
** Can treat for either three weeks or response-dependent
* Bronchoscopy indications
** Failing medical management
** High-risk features - symptoms for >3 months prior to treatment or cavities >4-6cm
** Can be used for either direct drainage or trans-bronchial catheterisation of the cavity
* Surgery
** Rarely required
** Indications:
*** Persistent cavity >=2cm and thick-walled
*** Failure to clear sepsis after 8 weeks of medical therapy
*** Haemoptysis 
*** Exclusion of cancer

[[Category:Thoracics]]