Atelectasis

AtelectasisAtelectasis is a complete or partial collapse of the lung or its part that causes hypoxia.

Description

Atelectasis occurs when the alveoli (air sacs of the lung) become deflated. Condition is a possible complication of other respiratory problems such as cystic fibrosis, pneumonia, lung tumors and chest traumas. Atelectasis may be acute or chronic.  Obstructive it is the most common type caused by the reabsorption of from the alveoli when communication between the alveoli and the trachea is obstructed.

Causes

Atelectasis may be obstructive or non-obstructive due to its cause.
Obstructive it is caused by a mucus buildup (“mucus plug” is associated with cystic fibrosis and asthma attack, infection (chronic fungal, bacterial and other infections of the lungs), foreign object (accidentally inhaling of small items), tumor (an abnormal growth in the lungs can collapse the alveoli), blood clot.
Non-obstructive atelectasis occurs due to trauma of the chest, pleural effusion (accumulation of fluid in the pleural cavity outside of the lungs), pneumothorax (accumulation of the air in the pleural space causes the increase of the  pressure in the chest), large tumor. Adhesive atelectasis results from surfactant deficiency. Surfactant normally reduces the surface tension of the alveoli avoiding the collapse of the lung. Decreased production or inactivation of surfactant is observed in acute respiratory distress syndrome (ARDS) and similar disorders.


Risk factors

Atelectasis is more likely to occur in a person who undergoes artificial ventilation, general anesthesia, lung or chest surgery, experienced lung or chest injury, lung infection or lung diseases such as asthma, bronchiectasis or cystic fibrosis or suffer from neuromuscular diseases that impairs breathing. Prematurely born babies as well as children under the age of 3 and adults over age 60 are also at risk of developing atelectasis.

[See also: Sinusitis]


Symptoms

Most symptoms and signs are determined by the rapidity of the development of it occurs, the size of the lung area that is affected and the underlying cause. The main symptoms of the condition include cough, sometimes chest pain, breathing difficulties, cyanosis (the bluish or purplish discoloration of the skin or mucous membranes), tachycardia (increased heart rate) and low oxygen saturation.
Slowly developing atelectasis may be asymptomatic or may cause only minor symptoms. Hypotension, fever, and shock also occur sometimes.

Diagnosis

The main way to evaluate the diagnosis is to perform an x-ray examination. It  is almost always associated with a linear increased density on chest x-ray. To find out the underlying cause of the condition CT and bronchosopy are recommended.

Treatment

The aim of treatment is to restore the normal alveolar filling. Treatment is based on the management of the underlying cause.
Minor atelectasis does not require medical assesment, because it can subside on its own. Following treatment may be needed depending on the cause:

    • Atelectasis after the  surgery is treated by deep breathing and coughing exercises.
    • Atelectasis caused by external pressure from a tumor or fluid is focused on the  removing the tumor, or draining the fluid.
    • A physical obstruction of the airway can be removed surgically or via bronchoscopy. A mucus plug is loosened using medication or chest percussions. Bronchodilators (albuterol, metaproterenol) and mucolytic agents (N-acetylcysteine, dornase alfa)  may be used to cause  sputum expectoration.
    • Illness: Infections and other lung disorders are treated with appropriate therapies.Antibiotics (cefuroxime, cefaclor) are used to treat underlying bronchitis or postobstructive infection.

In some cases, people may require supplemental oxygen, continuous positive airway pressure, or, rarely, insertion of a breathing tube (endotracheal intubation) and mechanical ventilation.

If endobronchial lesions are suspected fiberoptic bronchoscopy is performed.
Chronic atelectasis is treated with segmental resection or lobectomy.