A patient with shortness of breath and tracheal deviation after a road traffic accident, with a chest X-ray showing lung expansion and a shifted mediastinum, what is the diagnosis?

Diagnosis: Tension Pneumothorax

This patient has a tension pneumothorax on the right side, causing leftward tracheal deviation and mediastinal shift—this is a life-threatening emergency requiring immediate needle decompression without waiting for any further imaging or confirmation. 1, 2

Clinical Reasoning

The presentation is pathognomonic for tension pneumothorax:

• Post-trauma shortness of breath with tracheal deviation to the left indicates that the right hemithorax has accumulated air under pressure, pushing the mediastinum away from the affected side 3, 2
• "Expanded lungs" on chest X-ray likely describes hyperinflation/hyperlucency of the affected right lung field 1
• "Widened mediastinum" on the X-ray actually represents mediastinal shift, not true widening—this is the radiographic correlate of the tracheal deviation found on physical exam 4, 5

Why Not the Other Options?

Cardiac tamponade (Option B): Would present with distended neck veins, muffled heart sounds, and hypotension (Beck's triad), but would NOT cause tracheal deviation or unilateral lung hyperexpansion 3. The mediastinum remains central in tamponade.

Pleural effusion (Option C): Would cause tracheal deviation TOWARD the affected side (not away), dullness to percussion (not hyperresonance), and would show opacity (not hyperlucency) on chest X-ray 3.

Esophageal rupture (Option D): Typically presents with subcutaneous emphysema, mediastinal air, and often pneumothorax, but the clinical picture would include severe pain after vomiting/instrumentation, and would not explain the degree of respiratory distress and mediastinal shift seen here 3.

Immediate Management Required

Do NOT delay treatment for additional imaging—tension pneumothorax is a clinical diagnosis and waiting for confirmation can be fatal within minutes. 1, 2

1. Immediate needle decompression at the 2nd intercostal space, midclavicular line using a minimum 7-8 cm needle (No. 14 gauge, 8.25 cm length recommended) 3, 1, 2
2. Follow immediately with tube thoracostomy at the 4th-5th intercostal space, midaxillary line—the needle is only temporizing 3, 1, 2
3. Connect to underwater seal drainage and confirm bubbling before removing the decompression needle 1

Critical Pitfall to Avoid

The classic teaching that tracheal deviation is a late finding is misleading—tension pneumothorax can develop rapidly after trauma, and mediastinal shift (manifesting as tracheal deviation) can occur early, especially in the setting of positive pressure or mechanical stress from the injury. 1, 4 The patient may still be relatively stable hemodynamically when tracheal deviation is first noted, but deterioration can be sudden and catastrophic. 5