When air enters the pleural cavity, it is called pneumothorax
Causes partial or complete collapse of the affected lung
Etiology
Pneumothorax can occur without an obvious cause or injury (i.e., spontaneous pneumothorax)
As a result of direct injury to the chest or major airways
Rib fractures- cause restriction of breathing due to pain
Classification
Open- air enters chest during inspiration and exits during expiration
Closed- air can enter during inspiration but not exit during expiration
Causes pressure build up inside chest
More dangerous
Tension- air can enter but cannot leave
Pathophysiology
The pressure gradient inside the thorax changes with a pneumothorax
Usually, the pressure of the pleural space is negative when compared with atm
When there is communication between the alveoli and the pleural space, air fills this space changing the gradient, lung collapse unit equilibrium is achieved, or the rupture is sealed.
Pneumothorax enlarges, and the lung gets smaller due to this vital capacity, and oxygen partial pressure decreases
Spontaneous pneumothorax
Occurs when an air-filled bleb, or blister, on the lung surface ruptures
Rupture allows atmospheric air from the airways to enter the pleural cavity
Air continues to flow into the pleural space until a pressure gradient no longer exists or until the decline in lung size causes the leak to seal
Primary spontaneous pneumothorax occurs in otherwise healthy persons.
Secondary spontaneous pneumothorax occurs in persons with underlying lung disease.
Examples are asthma, TB, cystic fibrosis, sarcoidosis, carcinoma
Most common cause of secondary spontaneous pneumothorax is pulmonary emphysema (abnormal permanent enlargement of the air spaces distal to the terminal bronchioles)
Traumatic pneumothorax
Caused by penetrating or non-penetrating injuries
Fractured or dislocated ribs that penetrate the pleura are the most common cause
Breathing is restricted due to pain
Injury leads to tear in lung surface
Allows air to enter pleural cavity
This causes collapse of lung
Tension pneumothorax
Occurs when the intrapleural pressure exceeds atmospheric pressure
Occurs when injury to the chest or respiratory structures permits air to enter but not leave the pleural space
Wound or injury to chest wall forms a valve
Allows air to enter pleural cavity but not leave
This increases pressure in the chest
Build up of pressure can lead to many complications such as;
Atelectasis, shifting of mediastinal structures, compression of vena cava, narrowing of capillaries
Acute RH failure ensures due to vena cavae compression
Manifestations
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