Causes Of Atelectasis: Symptoms, Diagnosis And Treatment

Atelectasis is also called as collapse of lung. It is an imperfect expansion of the lung. It may be confined to a segment, a lobe or the whole lung.

Congenital Causes

  • It is also referred to as neonatal collapse. Non-aeration of lung at birth or developing soon after birth is not uncommon in premature or low birth weight babies because of under developed lungs.
  • It is also associated with neonatal hyaline membrane disease, laryngeal dysfunction and obstruction of air passage.

Acquired Causes Of Atelectasis

Acquired atelectasis is of 2 types:

  • Compression collapse: It occurs due to external compression of the lung as in pleural effusion, haemothorax, and pneumothorax or rarely by surgical procedures such as thoracoplasty.
  • Absorption collapse: It is more common and is produced by bronchial obstruction.
  • Intraluminal causes of obstruction are foreign body, inspissated mucus, tumors and aspirations of gastric contents e.g. during unconscious state or during anesthesia.
  • Causes within the wall of bronchus causing collapse include bronchial stricture, often due to tuberculosis or tumors.
  • Extrinsic causes: pressure on bronchus by enlarged lymph nodes, aortic aneurysm or enlarged left atrium may also lead to atelectasis.

Symptoms Of Atelectasis

  • A slowly developing atelectasis of a lobe may produce no symptoms.
  • A sudden or quick developing atelectasis is characterized by breathlessness and cough.
  • Massive atelectasis may be associated with cyanosis, tachycardia, restlessness and even circulatory collapse.
  • Limitation of chest excursion on the affected side and shift of trachea and heart to the same side.
  • Percussion note over collapsed area is impaired.
  • Bronchial breathing with bronchophony may be heard.
  • Massive atelectasis may be complicated by acute respiratory failure.
  • Repeated infections in atelectatic lobe may be present as recurrent pneumonia.

How To Diagnose Atelectasis?

  • Chest X-ray usually confirms the diagnosis in form of a shrunken lung, lobe or segment. Displacement of the fissure, elevation of diaphragm and a change in position of mediastinal structures are important clues to underlying atelectasis.
  • Bronchoscopy is mandatory in all cases of obstructive collapse.
  • Examination of bronchial expirate for acid fast bacilli and cytology is necessary.
  • CT-scan helps to locate a mass or lymph node as the cause for atelectasis.

Treatment Options For Atelectasis

  • After a chest or major abdominal surgery deep breathing exercises, steam inhalation and encouragement to cough should be given to prevent post operative atelectasis.
  • Specific treatment depends upon cause of collapse. If effusion or pneumothorax is responsible, this external compression should be removed first.
  • Aspirated material, mucus plugs and foreign body need bronchoscopic removal.