Lung abscess

Lung abscess is a type of

This pus-filled cavity is often caused by aspiration, which may occur during anesthesia, sedation, or unconsciousness from injury. Alcoholism is the most common condition predisposing to lung abscesses.

Lung abscess is considered primary (60%

]

Those with a lung abscess are generally

bronchial breath sounds

.

Complications

This section needs expansion. You can help by adding to it. (June 2018)

Although rare in modern times, can include spread of infection to other lung segments,

• Aspiration of
  gastric secretion
• Septic emboli
• Necrotizing pneumonia^[5]
• Vasculitis: Granulomatosis with polyangiitis
• Necrotizing
  squamous carcinoma
  of the lung is the most common.

Organisms

In the post-antibiotic era pattern of frequency is changing. In older studies anaerobes were found in up to 90% cases but they are much less frequent now.^[6]

• Streptococcus milleri
• Aerobic bacteria: Staphylococcus, Klebsiella, Haemophilus, Pseudomonas, Nocardia, Escherichia coli, Streptococcus, Mycobacterium^[8]
• Candida, Aspergillus, Histoplasma, Blastomyces, and Coccidioides
• Parasites: Entamoeba histolytica, Paragonimus

Diagnosis

Imaging studies

Lung abscesses are often on

Raised inflammatory markers (high ESR, CRP) are common but nonspecific. Examination of the coughed-up mucus is important in any lung infection and often reveals mixed bacterial flora. Transtracheal or transbronchial (via bronchoscopy) aspirates can also be cultured. Fiber optic bronchoscopy is often performed to exclude obstructive lesion; it also helps in bronchial drainage of pus.^{[citation needed]}

• 
  Pulmonary abscess on CT scan
• 
  Pulmonary abscess on CXR
• 
  Pathology image of a lung abscess.
• 
  A subpleural abscess.

Management

Broad spectrum antibiotic to cover mixed flora is the mainstay of treatment. Pulmonary physiotherapy and postural drainage are also important. Surgical procedures are required in selective patients for drainage or pulmonary resection.

The treatment is divided according to the type of abscess, acute or chronic. For acute cases the treatment is^{[citation needed][9][10]}

• antibiotics:
  • if anaerobic: metronidazole or clindamycin
  • if aerobic: beta-lactams, cephalosporins
  • if
    MRSA or Staphylococcus infection: vancomycin or linezolid
• postural drainage and chest physiotherapy
• bronchoscopy is used for the following cases:
  • aspiration or instillation of antibiotics
  • patients with atypical presentation suspected of having underlying foreign body or malignancy

Most cases respond to antibiotics and prognosis is usually excellent unless there is a debilitating underlying condition. Mortality from lung abscess alone is around 5% and is improving.[10]^[11]

See also

• Empyema
• Bronchiectasis
• Abscess
• Pleural effusion

References