Atelectasis involves collapse of a region or the entire lungs. Once this occurs, fresh air could not reach the smaller airways of the lungs, specifically the alveoli and the exchange of oxygen and carbon dioxide will not take place. This results to diminished levels of oxygen being delivered to the organs and tissues of the body.
Even though atelectasis can be acute which occurs abruptly over a span of a few minutes, it can also be chronic which develops over a period of days up to weeks.
What are the signs and symptoms of atelectasis?
Atelectasis might have few or no symptoms at all if it develops in a slow pace or involves only a limited area of the lungs. On the other hand, if the condition affects a larger area or develops in a rapid manner, the symptoms can be dramatic and even progress to shock. The usual symptoms of the condition include the following:
- Coughing that is often described as hacking and usually non-productive
- Shortness of breath
- Pleurisy which involves a piercing sensation and worsens during deep breathing or coughing
- Fever can occur if complications such as pneumonia develops
- Cyanosis or bluish discoloration of the skin occurs if a number of alveoli are blocked, thus oxygen could not reach the blood.
- Shock is characterized by a rapid heart rate and low blood pressure which occurs if the condition occurs abruptly or covers a large area of the lungs.
What are the causes?
The main mechanisms that can lead to the development of atelectasis include the following:
If there is blockage of the airway either from the inside or exteriorly, it can lead to a collapse in a region of the lung.
The compression of the airways in the lungs can be caused by air or fluid surrounding the lungs, presence of tumors or cancers, enlargement or aneurysm of the heart, enlarged lymph nodes, lymphomas or abdominal distention that places pressure on the lungs.
Inability to take deep breaths can result to collapse of a region in the lungs. This is common during surgery particularly with general anesthesia and when the breathing is shallow due to pain. This is considered as the common cause of atelectasis.
The alveoli are kept open by a surfactant. Once this substance is absent, the lungs eventually lose surface tension and collapse. This is considered as the cause for respiratory distress among newborns. The loss of surfactant can also occur among adults who have adult respiratory distress syndrome, kidney failure and smoke inhalation.
Potential risk factors
There are certain factors that increases the risk for developing atelectasis. Most of these can predispose the individual to airway obstruction that leads to compression of the lungs or causes one to breathe less deeply than normal. The usual risk factors include the following:
- General anesthesia
- Surgery especially those that involve the chest or upper abdomen
- Pleural effusion both benign and malignant can crush the airways
- Certain lung conditions such as cystic fibrosis and COPD can produce mucous plugs
- Rib fractures and other forms of chest injuries
- Inhalation of foreign objects
- Immobility or an extended period of bed rest
- Reduced amount of surfactant especially in respiratory distress syndrome and ARDS
- Using tight bandages that limits respiration
- Chest deformities
- Neurological conditions such as multiple sclerosis, myasthenia gravis and amyotrophic lateral scoliosis
- Exposure to asbestos
- Use of sedatives and narcotics