Question

Empyema necessitatis is defined as so when

• A. Pleural empyema is under pressure
• B. Pleural empyema has ruptured into the bronchus
• C. Pleural empyema has ruptured into the pericardium
• D. Pleural empyema is showing extension to the subcutaneous tissue

Hint:

The word necessitatis points to pus tracking outward through the chest wall.

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
The question asks for the exact meaning of the term empyema necessitatis, a specific complication of pleural empyema (pus collected in the pleural space).

Step 2: Key Formula or Approach:
Empyema necessitatis describes pus that, instead of staying inside the pleural space, tracks outward through the chest wall and points as a swelling under the skin.

Step 3: Detailed Explanation:
This happens when a long standing empyema, classically caused by tuberculosis or actinomycosis, erodes through the parietal pleura and intercostal tissues, dissecting along the path of least resistance until it reaches the subcutaneous tissue of the chest wall.
The pleural pus simply being under pressure inside the pleural space does not by itself define necessitatis, since pressure alone does not describe where the pus has tracked to.
When pus ruptures into a bronchus instead, it is called a bronchopleural fistula, a different named complication, not empyema necessitatis.
Rupture into the pericardium is not the standard definition used for either bronchopleural fistula or empyema necessitatis, and is not the classic pathway described here.

Step 4: Final Answer:
Empyema necessitatis means the pleural empyema has tracked out and is showing extension to the subcutaneous tissue.