Atelectasis vs bronchiectasis

Atelectasia

Atelectasis is defined as a sudden collapse of lung tissue due to obstruction of the bronchial tubes resulting in reduced or absent gas exchange. It may occur partially or over an entire lung region. Bronchiectasis is a localized destruction of lung tissue due to loss of elastin in the walls of the airways. There is an irreversible dilatation of the airways in bronchiectasis caused due to the destruction and it is classified under obstructive lung diseases. Both atelectasis and bronchiectasis cause obstructive lung diseases but the pathology is very different. In the former there is sudden blockage and in the latter there is gradual destruction leading to dilatation.

The commonest etiology of atelectasis is post surgery of the chest, due to an obstruction caused inside the airway lumen, growth from the air passage wall or compression of the airway caused from outside the lumen. Thick mucus plugs or foreign bodies can cause obstructions from inside the lumen, tumors may arise from the wall and finally any tumor or lymph node arising and compressing the lumen from outside can lead to a sudden blockage of the tubes. There are congenital and acquired causes for bronchiectasis but the acquired ones are found most often. Amongst the acquired causes, common are inhalation of foreign bodies, tuberculosis, pneumonia, and infections with bacteria like staphylococcus and klebsiella. The congenital causes of bronchiectasis consist of Young’s Syndrome, Kartagener’s Syndrome or Cystic fibrosis in which there is inflammation and a reduced clearance of alveolar fluid. In atelectasis, post blockage the air is absorbed from the alveoli into the blood and then retraction of the lung tissue occurs. This emptied alveolar space may later be filled with alveolar fluid and cells, due to which the lung gets distended displacing many structures.

In bronchiectasis, there is excessive coughing and increased expectoration (phlegm) which is greenish yellow in color. This is the most marked distinguishing feature which differentiates it from other respiratory diseases. Later on, dyspnea (breathlessness) is seen along with fever. In atelectasis, the symptoms depend upon the rapidity with which the block occurs and the portion of the lung where the blockage forms.
Depending upon it there may be sudden onset of dyspnea first followed by hypoxia, hypotension and cyanosis and death may ensue. If the area affected is very small then there may be just dyspnea and a dry cough with mild chest pain. Hence, both the diseases are easily distinguishable based on their causes and the symptoms. On X-ray, atelectasis will be seen as opacification of lung tissue or collapse of one lobe or an entire lung whereas bronchiectasis will be better diagnosed on CT scan where it shows presence of beady and cyst-like spaces which are very specific to bronchiectasis. Sputum test is important as it reveals the organism causing infection and accordingly antibiotics can be started. Chest physiotherapy is helpful in removing the obstruction and flexible fiber optic bronchoscopy is essential to find out and remove the blocking agent in case of atelectasis. To treat bronchiectasis, intake of appropriate antibiotics is essential along with aggressive physiotherapy and use of bronchodilators.
Summary: Atelactasis is an acute malfunction of the lung tissue due to a block in the air passage leading to sudden difficulty in breathing. Bronchiectasis is a chronic, gradual destruction of the terminal air passages along with accumulation of fluid. Atelectasis is avoidable if proper care is taken post surgery whereas bronchiectasis is an irreversible destruction caused to the lung tissue which can only be treated by palliative methods.

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