Lung Abscess

Question 1

Définition lung abscess

Answer 1

Llocalized suppuration in lung parenchyma more than 2cm diameter usually

Question 2

Most common causes of lung abscess

Answer 2

Infection ( 90% anaerobes )
Neoplasm

Question 3

What is necrotizing or suppurative pneumonia also known as lung gangrene

Answer 3

Formation of mutilple small abscesses in the lung

Question 4

T or F , lung abscess are generally due to polymicrobial infections

Answer 4

True

Question 5

Common agent involved

Answer 5

Staph aureus
Strep milleri/ intermedius
Klebsiella pneumoniae
Pseudomonas aeruginosa

Question 6

Gram negative organisms that can be involved in lung abscess

Answer 6

Proteus species
Aerobacter species
E coli

Question 7

Positive organisms that can be involved in lung abscess

Answer 7

Peptostreptococcus
Micro aero Philip
Clostridium species
Staph

Question 8

Risk factors of lung abscess

Answer 8

aspiration of oro pharyngeal flora Conditions predisposing to aspiration Necrotizing pneumonia
Hematogenous spread from distal site
Preexisting lung disease (Bronchiectasis, Cystic fibrosis)
Bronchial obstruction
Infected pulmonary infarct
Immunodeficiency (acquired or primary)

Question 9

Classification of lung abscess

Answer 9

Primary abscess
Secondary abscess

Question 10

Main origin of primary abscess

Answer 10

Infectious

Question 11

Conséquence of primary abscess

Answer 11

Form necrosis in existing parenchyma process in patient predisposed to aspiration or pneumonia

Question 12

Cause of secondary abscess

Answer 12

Complications of preexisting local lesion (lung ca, bronchiectasis ) , systemic dx (HIV, spread from extra pulmonary location )

Question 13

Pathogenesis of lung abscess

Answer 13

Pneumonitis leading to necrosis 7-14 days after which leads to abscess , empyema, or both

Question 14

Clinical presentation of lung abscess

Answer 14

Present like empyema with purulent sputum , hemoptysis and digital clubbing

Question 15

Investigation for lung abscess

Answer 15

Imaging (Chest X ray, Pleural ultrasonography ,CT scan Chest)

Diagnostic thoracocentesis (Macroscopic features of purulent / turbid fluid, Positive bacterial cultures, Glucose <40mg/dl, PH<7.1 , LDH>1000 IU/L, ADA > 60 U/L IN tuberculous pleural empyema)

Others (Flexible bronchoscopy => bronchial fistula/ obstruction , Pleural biopsy, Diagnostic videothoracoscopy, Diagnostic thoracotomy, Sputum culture , Pleural fluid culture, Blood culture sometimes ,Pleural fluid PCR or strep antigen )

Question 16

Poor prognostic factor for failure of treatment

Answer 16

large abscess more than 6cm
Compromised immunity
Neoplasm
Advanced age
Thick walled cavity
Reduced level of consicousness
Infection with certain aerobic pathogens( klebsiellalneumoniae, Pseudomonas aeuriginosa, Staph aureus )

Question 17

Differentials of lung abscess

Answer 17

TB
Amoebic lung abscess
Septic emboli looking like metastatic lung abscess
Cavity pulmonary infarct
Wegener vasculitis
Bronchogenic carcinoma.
Metastatic carcinoma
Lymphoma

Question 18

Treatment of lung abscess

Answer 18

medical treatment in anaerobic infection-> clindamycin (600mg IV q8h followed by 150-300mg PO qid) for 6-8 weeks

Surgical care With failed medical therapy leading to Hemoptysis in bronchopleural fistula Or Empyema
Either Ct guided percutaneous drainage which is preferred or Lobectomy or pneumonectomy in severe case

Question 19

Lung abscess complications

Answer 19

• rupture into pleural space causing empyema
• Pleural fibrosis
• Hemoptysis
• Respiratory failure
• Bronchopleural fistula
• Pleural cutaneous fistula
• Metastatic abscess

Question 20

When is Prognosis of lung abscess good

Answer 20

Good in healthy people

Question 21

When is prognosis of lung abscess bad

Answer 21

Immunosupression
malignancy
nosocomial infections
reduced level of conscious
anemia
low albumin
• Lung abscess secondary to Organisms with high mortality rates
◦ Pseudomonas aeruginosa
◦ Staph aureus
◦ Klebsiella pneumoniae