Question 1
What is the primary radiologic feature of empyema on a CT scan?
A. Ground-glass opacities
B. Split pleura sign
C. Horizontal air-fluid level
D. Mosaic attenuation
Answer: B. Split pleura sign
Explanation: The split pleura sign is a hallmark CT finding in empyema, showing contrast enhancement of thickened visceral and parietal pleura due to inflammation.
Reference:
Radiopaedia: Empyema. “The split pleura sign is a key feature on contrast-enhanced CT in empyema.”
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Question 2
Which of the following differentiates empyema from a free-flowing pleural effusion?
A. Does not conform to gravity
B. Enhancing pleura on CT
C. Presence of septations
D. All of the above
Answer: D. All of the above
Explanation: Empyema is distinguished by loculated fluid that does not conform to gravity, enhancing pleura (split pleura sign), and septations seen on imaging.
Reference:
Radiology Key: Empyema vs. Pleural Effusion. “Empyema does not follow gravity, may have air bubbles, and shows enhancing pleura.”
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Question 3
What is the most common cause of empyema?
A. Tuberculosis
B. Esophageal perforation
C. Complication of bacterial pneumonia
D. Trauma
Answer: C. Complication of bacterial pneumonia
Explanation: Bacterial pneumonia, especially with organisms like Streptococcus pneumoniae or Staphylococcus aureus, is the leading cause of empyema.
Reference:
PubMed: Causes of Empyema. “Empyema most commonly occurs as a complication of bacterial pneumonia.”
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Question 4
Which of the following features on CT imaging indicates loculated empyema?
A. Air bubbles within the fluid matrix
B. Horizontal air-fluid level
C. Lack of pleural thickening
D. Free-flowing pleural fluid
Answer: A. Air bubbles within the fluid matrix
Explanation: Air bubbles within the matrix indicate loculated empyema and are often due to gas-producing organisms or loculation.
Reference:
Radiographics: Imaging Features of Empyema. “Air bubbles in empyema suggest loculation and possible gas-producing organisms.”
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Question 5
Which laboratory test in pleural fluid analysis is most indicative of empyema?
A. Low glucose level
B. High pH
C. Low lactate dehydrogenase (LDH)
D. High albumin
Answer: A. Low glucose level
Explanation: Low pleural fluid glucose (<40 mg/dL) is a common finding in empyema due to the metabolic activity of bacteria and neutrophils.
Reference:
ATS Guidelines: Pleural Fluid Analysis in Empyema. “Low glucose and high LDH are indicative of empyema.”
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Question 6
What is the primary imaging modality used to guide thoracentesis in empyema?
A. MRI
B. CT
C. Ultrasound
D. Chest X-ray
Answer: C. Ultrasound
Explanation: Ultrasound is the preferred imaging modality for guiding thoracentesis due to its ability to detect fluid, loculations, and septations in real-time.
Reference:
Radiopaedia: Ultrasound in Empyema. “Ultrasound is ideal for guiding thoracentesis in empyema.”
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Question 7
What distinguishes empyema from an abscess on imaging?
A. Enhancing pleura in empyema
B. Location within the pleural cavity for empyema
C. Central air-fluid level in an abscess
D. All of the above
Answer: D. All of the above
Explanation: Empyema occurs in the pleural cavity with enhancing pleura, while abscesses are parenchymal and show central air-fluid levels.
Reference:
Radiology Key: Empyema vs. Abscess. “Empyema has pleural involvement, while abscesses are intraparenchymal.”
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Question 8
Which of the following phases describes the progression of empyema?
A. Exudative ? Fibrinopurulent ? Organizing
B. Transudative ? Purulent ? Septated
C. Fibrinopurulent ? Exudative ? Encapsulated
D. Reactive ? Suppurative ? Consolidating
Answer: A. Exudative ? Fibrinopurulent ? Organizing
Explanation: Empyema progresses through an exudative phase, a fibrinopurulent phase with loculations, and an organizing phase with fibrosis.
Reference:
Radiopaedia: Stages of Empyema. “The three phases include exudative, fibrinopurulent, and organizing stages.”
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Question 9
What is the role of fibrinolytics in the management of empyema?
A. Promote drainage of loculated fluid
B. Prevent fibrosis
C. Replace antibiotics
D. Seal air leaks
Answer: A. Promote drainage of loculated fluid
Explanation: Fibrinolytics like tissue plasminogen activator (tPA) are used to break down fibrin septations and enhance drainage in loculated empyema.
Reference:
ATS Guidelines: Fibrinolytics in Empyema. “Fibrinolytics help to break down septations for better drainage.”
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Question 10
Which of the following is a complication of untreated empyema?
A. Bronchopleural fistula
B. Pleural fibrosis
C. Empyema necessitans
D. All of the above
Answer: D. All of the above
Explanation: Untreated empyema can lead to complications like bronchopleural fistula, pleural fibrosis, and empyema necessitans (extension through the chest wall).
Reference:
PubMed: Complications of Empyema. “Untreated empyema can cause bronchopleural fistula, fibrosis, and chest wall extension.”
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