A 70-year-old with massive left pleural effusion on CXR shows mediastinal shift to the RIGHT. This finding indicates:
- A A large free effusion with mass effect ✓
- B Associated collapse of the left lower lobe
- C Carcinoma of the left main bronchus with obstructive collapse and effusion
- D Tension pneumothorax on the left side
Explanation
In a large pleural effusion, the mediastinum typically shifts AWAY from the side of effusion (towards the contralateral side) — indicating mass effect from the fluid. When the mediastinum shifts TOWARDS the effusion, it implies either: (1) ipsilateral lung collapse/atelectasis pulling the mediastinum toward it, or (2) contralateral volume loss. The question states shift to the right with a left effusion — this means shift AWAY from the left effusion, confirming a large free effusion with mass effect. If the mediastinum were central or shifted to the left (same side as effusion), this would raise concern for obstructive collapse.
Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.
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Written and medically reviewed by the StethoPrep medical team.