Spontaneous Pneumothorax.

Spontaneous Pneumothorax

PKGhatak, MD

A slender tall young man around 20 yrs. old suddenly feels sharp chest pain and soon develops shortness of breath. He is told in the ER that he has pneumothorax. His medical and family history does not point to the cause of his illness and the term Spontaneous pneumothorax is used to describe the incidence.

Most frequently, chest wall injuries from an automobile accident and rib fractures, gunshot wounds, and knife attacks, are the common traumatic causes of pneumothorax; pulmonary emphysema, cystic diseases of the lung, and use of ventilators are other main causes of pneumothorax.

Spontaneous pneumothorax results from the rupture of a small subpleural bleb. Usually, 10 to 30 subpleural blebs develop due to inherited diseases or poorly repaired deceased lung tissue. Anyone of these blebs may open up during straining, lifting heavyweight, or without an apparent reason. The outside air pressure is higher than normal pleural cavity pressure.  Any breach in the integrity of lung tissue or airways, the outside air freely enters the pleural cavity. The air around the lung tissues sneezes lung and a lobe of a lung or the entire one side may collapse and that causes shortness of breath. 

Incidence of spontaneous pneumothorax.

The incidence in men is 10 per 100,000 male population per year; in women, the incidence is 4 per 100,000 per year. A tall young person's growth spurts out spaces the growth of lungs, the resultant lung connective tissues are thinly spread out and air sacs can easily form.

Inherited conditions.

Mutation of the FLCN gene accounts for 40 % of spontaneous pneumothorax. FLCN gene codes for a protein Folliculin. Folliculin promotes cell division and cell growth and in addition confers elastic properties. The disease was previously known as Birt-Hogg-Dube syndrome - a constellation of skin tumors, renal cancer, multiple pulmonary cysts and recurrent pneumothorax. The disease is inherited by an autosomal dominant pattern.

Machado- Joseph Disease. It is also inherited by the autosomal dominant mode. This disease manifests as spinocerebellar ataxia and recurrent spontaneous pneumothorax.

Other disease associations are - Marfan syndrome and Homocystinuria.

Management of spontaneous pneumothorax.

Once the diagnosis is confirmed and if the pneumothorax is small (less than 15 % of the chest cavity) the patient is watched in ER for 4 to 6 hrs. Oxygen therapy and pain medication may or may not be required. If the patient is stable and comfortable then the patient is discharged with instructions and subsequent follow up telephone calls.

A larger pneumothorax is evacuated by inserting an intercostal chest tube at the most dependent site. The chest tube usually is self retained and secured at the insertion site by a retention suture. The wound is dressed by a sterile dressing impregnated with medical Vaseline. The distal end of the chest tube is positioned underwater seal and a suction device is used. A Series of air bubbles are seen to come out initially and the lung expands, and healing starts. When the air bubble ceases then a clamp is applied to the chest tube and after several hours later chest x-ray is obtained to confirm the full expansion of the lung and absent pneumothorax. Then the patient is ready for discharge.

Recurrence rate in non-gene spontaneous pneumothorax.                            In about 10 to 30 % of cases, the pneumothorax may recur.

Complications.

Check valve formation and Tension Pneumothorax.                                          This is an emergency situation. The pleural pressure keeps increasing with each breath and the air outlet is blocked by a tissue flap. The other normal lung is displaced laterally and the heart and larger blood vessels are compressed and displaced. Cardiac output falls and severe hypoxemia and hypotension and shock follow. The situation must be corrected by inserting a wide bore needle in the chest cavity and then thoracic surgery is required.

Prolonged healing or no improvement of pneumothorax.                              Repair, resection, or segmental lobectomy may be required to ensure a permanent closure of the damaged lung tissue.

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