Lung Abscess

A lung abscess is a collection of pus and dead lung tissue inside the lung itself that results from a bacterial infection. It is sometimes called “necrotizing pneumonia” or “lung gangrene.”


Due to anaerobic bacteria (living without oxygen) found in the mouth, most lung abscesses occur when you aspirate (saliva goes down the windpipe). This can happen if you lose consciousness or have difficulty swallowing (dysphagia).

Other aggressive aerobic bacterial infections, such as Streptococcus, Staphylococcus, Haemophilus, can cause lung abscesses as well.


Symptoms develop slowly over weeks.

  • Fever
  • Cough
  • Sputum (mixture of saliva and mucus) production with pus
  • Putrid or sour tasting phlegm
  • Night sweats
  • Weight loss
  • Coughing blood (hemoptysis)
  • Chest pain, especially while inhaling (pleurisy)

Diagnosing Lung Abscess

  • Chest X-ray: shows the location of the abscess
  • CT scan chest: shows a cavity, in the middle of the lung, filled with air and fluid 


  • Initially, antibiotics are delivered intravenously. The duration of antibiotics depends on clinical response but can last three to eight weeks, often followed by a course of oral antibiotics.
  • Drainage may be required for abscess cavities that are 6 centimeters or larger in diameter. This can be done using a CT scan to guide a drain through the chest wall into the abscess.
  • Very rarely, a portion of the lung containing the abscess must be removed surgically to clear the infection.

Other Lung Infections

Occasionally unusual bacteria, such as mycobacterium avium-intracellulare, or fungus, such as coccidioidomycosis or aspergillus, can cause lung infections. These infections typically appear as nodules or tumors.

Atypical infections are often seen in people with a weakened immune system that may be related to excessive alcohol intake, steroids or chemotherapy, among other things. If these infections do not respond to medical treatment, antibiotics, or antifungals, surgery may be required to remove the piece of lung containing the infection.