Lung Abscess - Diagnosis and Management Summary



Lung Abscess Etiology:

 • Necrosis of lung parenchyma by a polymicrobial infection

 • Most common cause: Aspiration pneumonia

 • DM risk factor for Klebsiella pneumonia

 • Chronic alcoholism

 • Periodontal disease/poor dentition/gingival disease

 • IV substance use

 • Esophageal dysmotility

 • Depressed consciousness

 • Large volume feeding tubes



Lung Abscess Pathophysiology:

1. Inoculum

2. Pneumonitis

3. Tissue necrosis (7-14 days later)

4. Lung abscess



Lung Abscess - Clinical Presentation:

 • 80% have fever ≥ 38 degrees

 • Chills, night sweats, fatigue, unexplained weight loss

 • Late disease: Pleuritic chest pain, hemoptysis, dyspnea, productive cough

 • Putrid sputum/sour-tasting sputum



Lung Abscess - Physical Exam:

 • Poor dentition

 • Gingival crevice disease

 • Diminished breath sounds

 • Rales



Lung Abscess Diagnosis:

 • CBC - Leukocytosis, anemia

 • Sputum/Blood cultures

 • CXR (non-diagnostic in early disease)

 • CXR upright or lat decubitus - air fluid level seen

 • Chest CT



Lung Abscess Management:

 • Antibiotics:

	- IV Ampicillin-sulbactam

	- Piperacillin/Tazobactam - pseudomonas

	- Carbapenems

	- IV Clindamycin in case of PCN allergy

	- Switch to oral antibiotics once stable

	- 10-15% require lobectomy or pneumonectomy if fail antibiotics

 • Consider Surgical Intervention:

	- Fevers > 10 days

	- Hemoptysis

	- Cavitation > 6 cm

	- Neoplasm, or hemorrhage

 • Treatment duration: 

	- 3 weeks or continue antibiotic treatment until the chest radiograph shows a small, stable residual lesion or is clear. This generally requires several months of treatment

 • Delayed response: Evaluate for foreign body, cancer, or bronchial stenosis



Lung Abscess Pathogens:

 • Aerobic Bacteria:

	- Staph. Aureus

	- Legionella

	- H. Influenza

	- E. Coli

	- P. Aeruginosa

	- Strep. Pyogenes

	- K. Pneumonia

 • Anaerobic Bacteria:

	- Bacteroides

	- Fusobacterium

	- Peptostreptococcus

	- Prevotella

 • Fungal:

	- Aspergillosis

	- Blastomyces

	- Dermatitidis

	- Cryptococcus

	- Coccidioides

 • Parasite:

	- Entamoeba histolytica

	- Paragonimus westermani

 • Other: TB, M. avium, M. kansii



Lung Abscess Differential Diagnosis:

 • Vasculitis (e.g., Granulomatosis with polyangiitis)

 • Malignancy

 • Aspirated foreign body

 • Bronchostenosis



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