What is this Condition?
Collapsed lung is an accumulation of air or gas between the membranes that enclose the lungs. The amount of air or gas that's trapped determines the degree of lung collapse. In a tension pneumothorax, the air in the membranes is under higher pressure than air in the adjunct lung and blood vessels. Without prompt treatment, a tension or a large pneumothorax results in fatal lung and circulatory impairment.
Pneumothorax can also be classified as open or closed. In open pneumothorax (usually the result of injury), air flows between the lung membranes and the outside of the body. In closed pneumothorax, air reaches the membrane space directly from the lung.
What Causes it?
Spontaneous pneumothorax usually occurs in otherwise healthy adults ages 20 to 40. It may be caused by air leakage from ruptured blebs (blisterlike accumulations of fluid) that are present at birth. It also may be caused by an emphysematous bleb that ruptures during exercise or coughing or from tuberculosis or cancer. The lung may also collapse spontaneously in interstitial lung disease.
Traumatic pneumothorax may be caused by chest surgery; a penetrating chest injury, such as a gunshot or knife wound; or the removal and analysis of lung tissue.
In tension pneumothorax, positive pressure in the lung membranes develops as a result of any of the causes of traumatic pneumothorax. When air enters the membrane through a tear in lung tissue and is unable to leave the same way, each inward breath traps air in the membrane, resulting in positive pressure. This in turn causes collapse of the lung and impaired return of blood through the veins. Decreased filling of the great veins of the chest diminishes cardiac output and lowers blood pressure.
What are its Symptoms?
The cardinal features of a collapsed lung are sudden, sharp chest pain (exacerbated by movement of the chest, breathing, and coughing); asymmetrical chest wall movement; shortness of breath; and bluish skin discoloration. In moderate to severe pneumothorax, substantial respiratory distress may develop, with signs of tension pneumothorax: weak and rapid pulse, pallor, neck vein distention, anxiety.
Tension pneumothorax produces the most severe respiratory symptoms; a spontaneous pneumothorax that releases only a small amount of air into the lung membrane may cause no symptoms.
How is it Diagnosed?
Sudden, sharp chest pain and shortness of breath suggest pneumothorax. A chest X-ray showing air in lung membrane confirms this diagnosis.
How is it Treated?
Treatment is conservative for spontaneous pneumothorax in which no signs of increased membrane pressure (indicating tension pneumothorax) appear, lung collapse is less than 30%, and the person has no shortness of breath or other signs of distress.
The treatment consist of bed rest; careful monitoring of blood pressure, pulse rate, and respirations; oxygen administration; and possibly, removal of air with a needle. If more than 30% of the lung has collapsed, a chest tube may be inserted to restore pressure.
Recurring spontaneous pneumothorax requires surgery. Traumatic and tension pneumothorax require chest tube drainage; traumatic pneumothorax may also require surgery.