Lung Abscess is a topic covered in the 5-Minute Clinical Consult.

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Basics

Description

  • The term lung abscess refers to a microbial infection of the lung that results in necrosis of pulmonary parenchyma typically forming a single walled-off cavity >2 cm in diameter (1).
  • Necrotizing pneumonia and lung gangrene, which are on the same clinical spectrum, are usually in multiple areas of the lung caused by a virulent pathogen.

Epidemiology

Incidence
  • In the age of antibiotics, this is a very uncommon infection, and the exact incidence is unknown.
  • Typically affects middle-aged men with predisposition to aspiration especially alcoholics (2)

Etiology and Pathophysiology

  • Most commonly, oral bacteria from the gingival crevice are aspirated which lead to inflammation and eventual liquefactive necrosis with abscess formation (2).
  • Less commonly, septic emboli from endocarditis and others
  • Because microbiologic growth is scant from sputum and invasive specimen procurement is rarely pursued, treatment is empiric.
  • Immunocompetent hosts: anaerobic bacteria and micro-aerophilic streptococci, occasionally Staphylococcus aureus especially MRSA
  • Immunocompromised: pseudomonas and gram-negative rods in addition to those mentioned above. Attention should also be paid to the possibility of atypical organisms like fungi, Nocardia, Rhodococcus, TB, and Actinomyces.
  • Rarely, amebic liver abscesses can rupture through the diaphragm and cause lung abscess; consider if there is history of prolonged stay in an endemic region.

Genetics
No known genetic pattern

Risk Factors

  • Aspiration risk factors
    • Alcohol intoxication (loss of consciousness)
    • Heroin and other CNS depressant drugs
    • Seizure
    • General anesthesia with surgery
    • Dysphagia from muscular dysfunction either local or systemic
    • Tracheal/nasogastric tube and severe GERD
  • Airway obstruction
    • Neoplasia
    • External compression from lymph nodes
    • Endobronchial foreign bodies
  • Immune compromise
    • Neutropenia
    • Malignancy and chemotherapy
    • HIV infection
    • Chronic steroid use
    • Cystic fibrosis

General Prevention

  • Treatment of predisposing diseases
  • Aspiration precautions
  • Treatment of periodontal diseases

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Citation

* When formatting your citation, note that all book, journal, and database titles should be italicized* Article titles in AMA citation format should be in sentence-case
TY - ELEC T1 - Lung Abscess ID - 816233 ED - Baldor,Robert A, ED - Domino,Frank J, ED - Golding,Jeremy, ED - Stephens,Mark B, BT - 5-Minute Clinical Consult, Updating UR - https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/816233/all/Lung_Abscess PB - Wolters Kluwer ET - 27 DB - Medicine Central DP - Unbound Medicine ER -