Which injury involves bleeding in the lung tissue and around the alveoli and interstitial space after blunt chest trauma?

• A. Hemothorax
• B. Pulmonary contusion
• C. Open pneumothorax
• D. Cardiac contusion

Answer: (B)

Pulmonary contusion is the bruising of lung tissue after blunt chest trauma, involving bleeding within the lung parenchyma and around the alveoli and in the interstitial space. This bleeding and edema injure the tiny blood vessels, causing a disruption of the air–blood barrier and a ventilation–perfusion mismatch that impairs oxygen transfer. Patients may be short of breath and hypoxic, and crackles can be heard, though lung sounds aren’t always dramatic initially. Chest x-rays can look normal early on, so CT is more sensitive for detecting contusion if symptoms persist.

This condition is different from a hemothorax, where blood collects in the pleural space and reduces lung expansion with signs like decreased breath sounds and dullness to percussion; from an open pneumothorax, where air enters the chest through a chest wall wound and a penetrating injury is present; and from a cardiac contusion, which is trauma to the heart muscle itself and presents with chest pain, arrhythmias, or heart failure rather than bleeding within the lung tissue.

In the field, focus on airway and breathing: provide high‑flow oxygen and monitor for worsening respiratory distress, ready for advanced airway support if needed, and avoid fluid overload while evaluating for other injuries such as rib fractures or pneumothorax.