When air is drawn into the pleural space through this passageway, it is known as a "sucking chest wound". A closed pneumothorax is when the chest wall remains intact.Medical procedures, such as the insertion of a central venous catheter into one of the chest veins or the taking of biopsy samples from lung tissue, may lead to pneumothorax. The administration of positive pressure ventilation, either mechanical ventilation or non-invasive ventilation, can result in barotrauma (pressure-related injury) leading to a pneumothorax.Divers who breathe from an underwater apparatus are supplied with breathing gas at ambient pressure, which results in their lungs containing gas at higher than atmospheric pressure. Divers breathing compressed air (such as when scuba diving) may develop a pneumothorax as a result of barotrauma from ascending just 1 metre (3 ft) while breath-holding with their lungs fully inflated. An additional problem in these cases is that those with other features of decompression sickness are typically treated in a diving chamber with hyperbaric therapy; this can lead to a small pneumothorax rapidly enlarging and causing features of tension. Newborn infants
Newborn babies between 3–9 days of birth with low birth weight have a higher risk of pneumothorax. Mechanism
The thoracic cavity is the space inside the chest that contains the lungs, heart, and numerous major blood vessels. On each side of the cavity, a pleural membrane covers the surface of lung (visceral pleura) and also lines the inside of the chest wall (parietal pleura). Normally, the two layers are separated by a small amount of lubricating serous fluid.
Known lung diseases that may significantly increase the risk for pneumothorax are

In children, additional causes include measles, echinococcosis, inhalation of a foreign body, and certain congenital malformations (congenital pulmonary airway malformation and congenital lobar emphysema).11.5% of people with a spontaneous pneumothorax have a family member who has previously experienced a pneumothorax. The hereditary conditions – Marfan syndrome, homocystinuria, Ehlers–Danlos syndromes, alpha 1-antitrypsin deficiency (which leads to emphysema), and Birt–Hogg–Dubé syndrome – have all been linked to familial pneumothorax. Generally, these conditions cause other signs and symptoms as well, and pneumothorax is not usually the primary finding. Birt–Hogg–Dubé syndrome is caused by mutations in the FLCN gene (located at chromosome 17p11.2), which encodes a protein named folliculin. FLCN mutations and lung lesions have also been identified in familial cases of pneumothorax where other features of Birt–Hogg–Dubé syndrome are absent. In addition to the genetic associations, the HLA haplotype A2B40 is also a genetic predisposition to PSP. Traumatic
A traumatic pneumothorax may result from either blunt trauma or penetrating injury to the chest wall. The most common mechanism is due to the penetration of sharp bony points at a new rib fracture, which damages lung tissue. Traumatic pneumothorax may also be observed in those exposed to blasts, even though there is no apparent injury to the chest.They may be classified as "open" or "closed". In an open pneumothorax, there is a passage from the external environment into the pleural space through the chest wall.