Pneumothorax

Pneumothorax describes a situation in which air accumulates in the space between the lung and the chest wall. This air prevents the lung from expanding fully, which can reduce the efficiency of breathing. The condition can arise spontaneously, follow an injury to the chest, or develop as a consequence of underlying lung disease. Owners often notice signs related to breathing effort—rapid or shallow breaths, reluctance to lie down, or a posture that suggests discomfort. In some cases the signs appear suddenly, while in others they build more gradually. The degree of distress varies widely depending on how much air has accumulated and how quickly it appeared. This page explores the patterns that may raise the question of pneumothorax, the mechanisms by which air enters and remains in this space, the imaging and other investigations used to confirm it, and the range of approaches—from observation through to procedures that remove the air—that may be considered depending on the circumstances.