Lung Abscess Surgery Differential Diagnoses

Updated: Mar 21, 2022
  • Author: Shabir Bhimji, MD, PhD; Chief Editor: Jeffrey C Milliken, MD  more...
  • Print

Diagnostic Considerations

Cavitary lesions in the lung parenchyma have several causes, but a patient with an acute presentation of an illness with air-fluid levels should elicit consideration of a lung abscess. Lung parenchymal cystic lesions and secondarily infected bullae can occasionally confuse the picture. The prior existence of these lesions, as documented by old radiographs and the segmental location, are not typical of lung abscess.

Patients with squamous cell bronchial carcinomas can also present with cavitary lesions that are sometimes difficult to differentiate from lung abscesses. Realizing that the wall of the carcinomatous abscess is usually thicker and more irregular than that of the primary abscess is helpful. Furthermore, foul sputum, no response to antibiotics, and the absence of fever may help distinguish the two entities.

Because an abscess distal to bronchial obstruction usually occurs in an area of lobar pneumonitis and atelectasis—but otherwise appears as a primary abscess—early bronchoscopy is recommended in all cases.

The differential diagnosis of a cavitary lung lesion includes the following:

  • Anaerobic infection - Gram-negative bacteria, Pseudomonas species, Legionella species, Haemophilus influenzae species
  • Infection by gram-positive bacteria - Staphylococcus species, Streptococcus species, Mycobacterium species
  • Fungal infection
  • Parasitic infection - Entamoeba histolytica, Paragonimus westermani
  • Sepsis - Embolism, cavitary infarction, bland infarction, Wegener vasculitis
  • Neoplasms - Bronchogenic carcinoma, metastatic carcinoma, lymphoma
  • Sequestration - Bulla with fluid, empyema with air fluid levels
  • Cystic lesions of the lung, infected emphysematous bullae and sequestration can be difficult to distinguish from a lung abscess