Pneumothorax consists of the presence of air within the pleural cavity, causing a partial or complete separation between the lung and the chest wall and resulting in lung collapse of varying severity. Depending on its cause, it can be classified as primary spontaneous pneumothorax, which usually appears in young patients with no known lung disease and is often related to the rupture of subpleural bullae or blebs; secondary spontaneous pneumothorax, associated with previous lung diseases such as COPD, emphysema or interstitial diseases; traumatic pneumothorax, secondary to chest trauma; and iatrogenic pneumothorax, related to medical procedures. The most severe form is tension pneumothorax, a potentially urgent situation due to respiratory and haemodynamic compromise.

The clinical presentation is usually characterised by the sudden onset of pleuritic chest pain, shortness of breath, a sensation of chest tightness and, occasionally, a dry cough. The intensity of the symptoms depends on the size of the pneumothorax, the speed of onset and the patient’s baseline lung function. Diagnosis is based on the medical history and physical examination, complemented by chest X-ray, which remains the most commonly used initial test. In selected cases, especially when it is necessary to assess underlying lung disease, identify bullae or plan surgical treatment, a computed tomography (CT) scan of the chest may be performed.