Which statement is true about pneumothorax progression?

• A. A simple pneumothorax can progress to a tension pneumothorax
• B. A simple pneumothorax cannot progress
• C. Pneumothorax is harmless
• D. None of the above

Answer: (A)

Progression happens because air can continue to leak into the pleural space and raise intrapleural pressure, creating a one-way-valve effect that traps air during inspiration but limits its exit. With ongoing air entry and rising pressure, the lung on the affected side collapses further and the mediastinum can shift, compressing the heart and great vessels and impairing venous return. This is the scenario of a tension pneumothorax, a life-threatening condition requiring immediate decompression. A simple pneumothorax may be stable at first, but it is not guaranteed to stay the same; it can worsen and become a tension pneumothorax under the right (or wrong) circumstances. Therefore, the statement that a simple pneumothorax can progress to a tension pneumothorax is true. The other options—claiming it cannot progress or that pneumothorax is harmless—are not accurate.