Pulmonary atelectasis is a medical term that describes the partial or complete collapse of the pulmonary alveoli, which are the microscopic sac-like structures where gas exchange takes place in the lungs.
What is atelectasis
Pulmonary atelectasis is the loss of volume in part or all of the lung due to alveolar emptying and collapse; it can occur for multiple reasons.
The alveoli play a crucial role in blood oxygenation, since in these structures oxygen from the air is transferred to the pulmonary capillaries; and when the alveoli collapse, the lung’s ability to exchange gases is reduced, causing hypoxemia, which is low oxygen levels in the blood.
Common causes of pulmonary atelectasis include airway obstructions, external pressure on the lung, or inactivity in patients who remain immobile for long periods.
Types of atelectasis
Depending on the mechanism that causes lung collapse, types of atelectasis are classified as follows:
- Obstructive atelectasis: occurs when something blocks airflow to the alveoli; it is the most common form of atelectasis and often occurs in patients with respiratory infections, postoperative cases, or after aspirating foreign bodies.
- Compressive atelectasis: caused by external pressure compressing the lungs, which may result from pleural effusion (fluid buildup) or the presence of air in the pleural cavity.
- Adhesive atelectasis: happens when there is a deficiency of pulmonary surfactant, a substance that reduces surface tension in the alveoli and prevents them from collapsing; this commonly occurs in premature newborns or in people with acute respiratory distress syndrome (ARDS).
- Cicatrization atelectasis: develops as a result of scarring or pulmonary fibrosis from previous infections such as tuberculosis or from chronic interstitial lung diseases.
- Rounded atelectasis: a rare type of atelectasis that is associated with chronic pleural diseases such as asbestos exposure. In this case, the lung collapses focally, forming a rounded structure that is visible in imaging studies.
Lung collapse
Although pulmonary atelectasis is a partial or complete collapse of the alveoli, it is a different condition from lung collapse or pneumothorax, which occurs when the lung loses its ability to expand due to the accumulation of air in the pleural cavity, resulting in separation between the lung and the chest wall.
Among the main differences is that in pulmonary atelectasis, the problem is located inside the lung, regardless of its cause, or due to a deficiency of pulmonary surfactant that keeps the alveoli open; whereas lung collapse results from a structural problem in the pleural cavity, such as a pleural perforation that allows air to enter and eliminates the negative pressure that normally keeps the lung expanded.
Treatment for pulmonary atelectasis will vary depending on its cause but may include respiratory physiotherapy, removal of airway obstructions, oxygen therapy, mechanical ventilation, and preventive measures in postoperative patients.
Pulmonary atelectasis is a common condition that can present in mild or severe forms and may become life-threatening.
At the ABC Medical Center’s Internal Medicine Department, we can provide you with specialized care. Contact us!
Fuentes:
Medline Plus, MSD Manuals, MAPFRE
