Surgery MCQs Q18

FreeMedSite

PULMONOLOGY • RADIOLOGY

A 59-year-old male chronic smoker undergoes a chest radiograph that reveals a cavitary lesion with an air–fluid level. Bronchoscopy has excluded malignancy.

What is the most likely diagnosis?

A Bronchiectasis

B Lung abscess

C Carcinoma of lung

D Hematoma

E Pulmonary embolism

Lung abscess. A cavitary lesion with an air-fluid level is the classic radiological hallmark of a lung abscess. Excluding malignancy via bronchoscopy makes this the definitive primary diagnosis.

Decoding Clue

1

CLUE "Cavity + air–fluid level + malignancy excluded"

TRANS Necrotic infection forming pus-filled cavity → Lung Abscess.

Explanation

B. Lung abscess: Correct. Localized suppurative destruction of lung parenchyma. Imaging shows a cavity with air-fluid level. Often caused by aspiration or anaerobic bacteria.

A. Bronchiectasis: Presents as dilated bronchi ("tram-track" or ring shadows), not a single discrete cavity with an air-fluid level.

C. Carcinoma: Squamous cell carcinoma can cavitate, but the prompt states malignancy has been excluded.

D. Hematoma: A collection of blood that typically does not show air–fluid levels unless secondarily infected.

E. Pulmonary embolism: Usually causes a wedge-shaped infarct (Hampton's hump); cavitation is very rare.

🧠 High-Yield Pearls

Feature	Finding / Detail	Clinical Significance
Imaging Sign	Air–fluid level	Indicates a cavity containing both gas and liquid (pus)
Common Pathogens	Anaerobes	Bacteroides, Fusobacterium; linked to foul-smelling sputum
Risk Factors	Aspiration	Alcoholism, poor dental hygiene, seizure disorders
1st Line Tx	Antibiotics	Prolonged course (e.g., Clindamycin)

Integrated Clinical Questions

1. Most common cause of lung abscess?

Answer: Aspiration of oropharyngeal contents.

2. Most characteristic sputum feature?

Answer: Foul-smelling sputum (suggests anaerobic infection).

3. First-line medical treatment?

Answer: Prolonged antibiotics (e.g., Clindamycin or Beta-lactam/Beta-lactamase inhibitor combinations like Amoxicillin-Clavulanate).

4. When is surgery indicated for a lung abscess?

Answer: Failure of medical therapy (prolonged fever/symptoms), suspicion of malignancy, or complications like massive hemoptysis.

5. Most common location for aspiration-related abscesses?

Answer: Superior segments of lower lobes or posterior segments of upper lobes (due to gravity in the recumbent position).

⚡ Exam Pearls

• Air-fluid level = think abscess until proven otherwise.
• Always exclude malignancy in smokers with cavitary lesions.
• Bronchoscopy is key for ruling out endobronchial obstruction or cancer.
• Infection + Necrosis = Cavity formation.

← Previous Next Question →

FreeMedSite • Open Medical Education