What is a symptom of simple (closed) pneumothorax?

A symptom of simple (closed) pneumothorax is chest pain on inspiration. This is because when air enters the pleural space, it can lead to irritation of the pleura, which are sensitive to pain. During inhalation, as the chest expands, this pain can be exacerbated due to the pressure changes in the thoracic cavity, causing discomfort and a sharp pain on the side of the pneumothorax.

While severe dyspnea is sometimes present in a pneumothorax, it is more commonly associated with larger or tension pneumothoraces. Frothy blood is typically seen in pulmonary edema or significant lung injuries, and a sucking chest wound is indicative of an open pneumothorax, not a simple closed pneumothorax. Thus, the presentation of chest pain with inspiration is a more accurate and specific symptom for simple (closed) pneumothorax.