5.6 : 気胸I：概要

A pneumothorax is an abnormal accumulation of air in the pleural space between the chest wall and the lungs.

This can lead to a loss of the normal negative pressure that keeps the lungs inflated, causing the lung to collapse either partially or completely.

There are three types of pneumothorax: spontaneous, traumatic, and tension.

Spontaneous pneumothorax occurs when tiny blebs on the surface of the lung rupture.

These blebs are often associated with conditions like COPD and emphysema, though less commonly with cystic fibrosis or pneumonia.

Traumatic pneumothorax, classified as either injury-related or iatrogenic, occurs due to physical trauma or medical procedures.

Injury-related pneumothorax results from chest trauma and penetrating injuries that puncture the lung.

Similarly, iatrogenic pneumothorax can result from lung puncture during medical procedures like lung biopsy or needle aspiration.

Lastly, tension pneumothorax occurs when air enters the pleural space through a lacerated lung or small chest wall opening and cannot escape, creating a one-way valve mechanism that affects breathing and circulation and causes lung collapse.