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Lung Abscess Bronchiectasis And Empyema

Lung Abscess, Bronchiectasis and Empyema

1. Definition

A pyogenic pneumonia develops, causing localized suppuration with parenchymal destruction. There is central necrosis of lung tissue, which then liquefies and communicates with the bronchial tree. This partial internal drainage results in the classic cavity with an air-fluid level.

2. Etiology

A. Aspiration
1) Location: predilection for the posterior segment of the RUL, the superior segment of the RLL, and the LLL
2) Bacteriology: anaerobes and aerobes
B. Post-pneumonic
1) Location: any segment, may be in multiple segments
2) Bacteriology: staphylococcus and streptococcus
C. Endobronchial obstruction
1) Neoplasms and foreign bodies can result in distal infection and abscess formation

3. Clinical Presentation

A. Symptoms
1) Fever, chills, severe cough, hemoptysis, and copious foul smelling sputum
B. Signs
1) Tachypnea, consolidation, local chest wall tenderness

4. Diagnosis

A. CXR: pneumonitis pattern early, followed by the air-fluid level when bronchial communication has been established
B. Bacteriological/fungal evaluation: aerobic, anaerobic, fungal, TB all important
C. Bronchoscopy is indicated to rule out obstructing foreign bodies or neoplasms and can provide drainage

5. Treatment

A. Most abscesses respond to bronchoscopy and appropriate medical treatment
B. Surgery reserved for medical failure, carcinoma, significant hemoptysis, and complications such as empyema and bronchopleural fistula
C. Lobectomy is typically required when resection is in order, as segmentectomy is often not possible and pneumonectomy rarely necessary
D. Percutaneous drainage can be useful in patients who are not candidates for standard surgical intervention

BRONCHIECTASIS

1. Definition

A. Chronic bronchial dilatation with parenchymal infection and inflammatory reaction. There are three types: cylindrical, varicose, and saccular/cystic.

2. Etiology

A. Acquired infection is the most common cause, typically when occurring in childhood.
B. Other acquired causes include bronchial obstruction and scarring
C. Congenital causes include cystic fibrosis, Kartagener's syndrome, various immunodeficiency disorders, and bronchopulmonary sequestration
D. Typically affects the basal segments of the lower lobes

3. Clinical presentation

A. Recurrent pneumonia, persistent cough, copious foul smelling sputum
B. Hemoptysis is common in adults but rare in children

4. Diagnosis

A. CXR usually demonstrates nonspecific findings, although a honeycomb pattern may be found
B. Bacteriologic studies typically return H. influenza, E. coli, and Klebsiella as the causative agents
C. Chest CT with fine cuts has replaced bronchography as the test of choice
D. Bronchoscopy can help localize the process, rule out obstructing lesions, and provide pulmonary toilet

5. Treatment

A. Medical therapy is the primary approach, using antibiotics, humidification, bronchodilators
B. Surgical intervention is indicated for failure of medical management, persistent symptoms, recurrent pneumonias, and hemoptysis
C. The ideal surgical candidate has unilateral disease confined to one lobe, usually lower
D. Most patients, however, have bilateral disease, and surgery should be reserved for localized disease, operating on the worst side first

EMPYEMA

1. Definition

Accumulation of pus within the pleural space. It occurs in three phases: exudative/acute phase, fibrinopurulent/transitional phase, and organizing/chronic phase.

2. Etiology

A. About half are secondary to a pneumonia (postpneumonic empyema)
B. Other causes include pulmonary or esophageal operations, chest trauma, spontaneous pneumothorax, and subphrenic abscess
C. Pneumonias caused by S. aureus, E. coli, Pseudomonas, and anaerobes are the most likely to result in empyema

3. Clinical Presentation

A. Pleuritic chest pain, fever, tachycardia, and tachypnea are common
B. Persistent fever after resolution of pneumonia is suspicious for empyema

4. Diagnosis

A. CXR may not differentiate pleural collection from lung consolidation or atelectasis
B. CT or US will help localize the fluid collection
C. Thoracentesis and aspiration of pus establishes the diagnosis
D. Chemical analysis of the fluid is critical
Empyema fluid characteristics
pH < 7.0
Glucose < 40 mg/dL
LDH > 1000 IU/dL
Positive Gram stain
Positive culture (50%)
Specific gravity > 1.018
WBC > 500 cells/mm3
Protein > 2.5 g/dL

5. Treatment

A. Acute and Transitional Empyema
1) Thoracentesis followed by chest tube insertion
2) Ensure complete drainage of all localized collections
B. Chronic Empyema
1) Open drainage with thorough cleansing of the cavity (saline or Dakin's solution)
2) Open chest tube drainage is then instituted, and the tube is slowly withdrawn at 10-14 day intervals
3) If the cavity is not closed after 6 weeks, a decortication (good candidates) or open rib resection or Eloesser flap (poor candidates) should be performed