Pneumothorax is the accumulation of air between the layers of the pleura surrounding the lungs. It is divided into two types: spontaneous and traumatic. Spontaneous pneumothorax is further divided into primary and secondary.
Primary Spontaneous Pneumothorax (PSP)
It most often occurs in tall, thin men between the ages of 20 and 30, and is rare before puberty and after the age of 40. In the United States it affects 20,000 people every year and causes an economic loss of 130 million dollars. It is 5 to 6 times more common in men. Some patients have a familial predisposition, and the predisposition is greater in women who develop pneumothorax. The most common cause of PSP is the rupture of small air sacs (blebs) at the lung apex (the upper part of the lung). Rupture of a bleb can occur during exertion or at rest. Exactly why these air sacs (blebs) form is not known. There are several theories, but none has been established with certainty:
• Greater negative pressure in the upper part of the lung,
• Ischemic causes,
• Smoking,
• Infections.
In tall, thin, asthenic individuals, the negative pressure at the apex is greater. PSP is seen more often in smokers, and there is a direct relationship between the amount smoked and the frequency of PSP; it is more common in heavy smokers. The recurrence rate was found to be 70% in those who continue smoking and 40% in those who quit. Bronchial anomalies are also seen more frequently, and this factor is independent of smoking. It is seen more often during periods of changing atmospheric pressure. In people with bullae in their lungs, air travel can cause rupture. Clinical presentation: chest pain, usually of sudden onset, localized to the site of rupture and present at rest. Shortness of breath, moderate tachycardia, hypotension and cyanosis suggest a tension pneumothorax. On physical examination: breath sounds are decreased on the side of the pneumothorax and that side moves less with breathing. The trachea is pushed (shifted) to the opposite side, the intercostal spaces widen on the affected side, vocal fremitus is decreased, and there is hyperresonance. ECG changes may be seen; on an upright chest X-ray, the shadow of the visceral pleura separated from the chest wall is visible. In some patients pleural fluid is present. Small pneumothoraces and bullae can also be seen on computed tomography of the thorax.
Treatment consists of evacuating the air, controlling the air leak, and reducing the likelihood of recurrence. Observation and nasal oxygen therapy, aspiration, tube thoracostomy, video-assisted surgery, or thoracotomy may be used.
Surgical Indications: An air leak lasting longer than 7 days, recurrent pneumothorax, bilateral pneumothorax, a history of pneumothorax on the opposite side, patients who have had a pneumonectomy (those with only one lung), occupational reasons (pilots and divers, long-haul captains, bus drivers, mountaineers), people living far from a hospital, and those in occupations of critical importance.