Necrotizing Pneumonia and Pulmonary Gangrene

Spectrum of Disease

  • Lung Abscess (see Lung Abscess, [[Lung Abscess]])
  • Necrotizing Pneumonia: pulmonary inflammation with alveolar filling (consolidation), peripheral necrosis, and multiple small cavities
    • Compromise of Bronchial and Pulmonary Vascular Supply: leads to devitalization of lung parenchyma and impedes antibiotic delivery -> uncontrolled infection and further destruction of lung tissue
    • Necrotizing pneumonia is more commonly associated with Gram-positive organisms (Staphylococcus Aureus, Streptococcus Pneumoniae)
  • Pulmonary Gangrene: final stage in the continuum of progressive devitalization of pulmonary parenchyma, characterized by sloughing of a pulmonary segment or lobe
    • Pulmonary gangrene is more commonly associated with Gram-negative organisms (Klebsiella, Pseudomonas), but may also occur with Gram-positive organisms (Streptococcus Pneumoniae)

Etiology


Physiology

  • Unkown Why Same Species of Organism Causes Necrotizing Pneumonia in One Host and Non-Necrotizing Pneumonia in Another Host
    • May be related to overall health/immune status of host, hsot inflammatory response, development of localized vasculitis with thrombosis of small and large vessels, siz of inoculum, virulence and antibiotic resistance pattern of pathogen, or a delay in seeking medical care

Diagnosis

  • Chest CT: best imaging modality to diagnose necrotizing pneumonia (and pulmonary gangrene)
    • Patchy lung inflammation with lack of perfusion: with lack of contrast uptake by the parenchyma
    • Microabscesses: may coalesce to form larger cavities (and may progress to frank pulmonary gangrene)
    • Radiographic Criteria for Pulmonary Gangrene (chest CT with IV contrast)
      • Obliteration of the pulmonary arterial supply to a segment/lobe containing large cavities and necrotic parenchyma (especially when necrosis affects >50% of the involved lobe)
      • Bronchial obstruction: may also be present
      • “Air Crescent Sign”: movable mass of devitalized tissue within the cavity

Clinical Manifestations

Pulmonary Manifestations

  • Acute Respiratory Failure (see Respiratory Failure, [[Respiratory Failure]])
  • Other Manifestations of Pneumonia (see Pneumonia, [[Pneumonia]])
    • Cough with Sputum Production (see Cough, [[Cough]])
    • Dyspnea (see Dyspnea, [[Dyspnea]])
  • Sepsis (see Sepsis, [[Sepsis]])

Other Manifestations

  • Fever (see Fever, [[Fever]])

Treatment

Antibiotics

  • Antibiotic Choice Needs to Be Guided by Early Identification of Organism: including antibiotic sensitivities

Pleural Drainage

  • Indicated for Cases with Associated Complicated Parapneumonia Effusion/Empyema

Percutaneous Drainage of Necrotizing Pneumonia

  • Contraindicated: due to inability to adequately debride necrotic lung parenchyma, rapid catheter obstruction (which are not amenable to the use of thrombolytics into the lung parenchyma), and the significantly increased risk of creation of a difficult to manage bronchopleural fistula

Surgical Resection

  • Indications
    • Massive Hemoptysis
    • Necrotizing Pneumonia Unresponsive to Medical Therapy
    • Pulmonary Gangrene
  • Optimal Timing of Surgery is Unclear

References

  • Mycobacterium chelonae necrotizing pneumonia after allogeneic hematopoietic stem cell transplant: report of clinical response to treatment with tigecycline. Transpl Infect Dis. 2009 Feb;11(1):57-63
  • Necrotizing pneumonia and empyema due to clostridium perfringens: Report of a case and review of the literature. The American Journal of Medicine; Volume 59, Issue 6, December 1975: 851-856
  • Necrotizing Pneumonia Caused by Mixed Infection with Actinobacillus actinomycetemcomitans and Actinomyces israelii: Case Report and Review. Clin Infect Dis. (1994) 18 (3): 450-452
  • Necrotizing pneumonia in bacteraemic pneumococcal infection. British Journal of Diseases of the Chest Volume 80, 1986, Pages 295-296
  • Massive necrotizing pneumonia with pulmonary gangrene. Ann Thorac Surg. 2009 Jan;87(1):310-1. doi: 10.1016/j.athoracsur.2008.05.077 [MEDLINE]
  • Management of necrotizing pneumonia and pulmonary gangrene: A case series and review of the literature. Can Respir J. 2014 Jul-Aug; 21(4): 239–245 [MEDLINE]