Can Atelectasis Cause Pleural Effusion?

When there is an obstruction in the lungs or a nervous dysfunction or irritation in the diaphragm or due to any other reason, the capacity of the lungs to transfer the gases is partially of completely lost, the condition is known as atelectasis. The condition is characterized by the collapse of the lungs. This may also be due to injury of the lungs or pleural effusion due to variety of reasons. The treatment may include removal of the obstruction or removal of the excess fluid through surgery in case of pleural effusion. Further, breathing exercises are also advised by the physician.

Can Atelectasis Cause Pleural Effusion?

Pleural cavity is the space between the two pulmonary membrane namely visceral and parietal pleurae. The pleural space normally contains fluid in the range of 5 to 10 ml. The function of this fluid is to lubricate the surface of the lungs during respiration process. The pleural fluid functions perfectly when present in the normal amount. However, when present in excess, may cause a serious trouble in breathing. This may be due to limit of the expansion of lungs by excess fluid. The occurrence of the larger amount of fluid than normal, in the pleural cavity, is termed as pleural effusion. The excess fluid may be blood, pus, urine or chyle. Pleural effusion may also be the reason for atelectasis. Atelectasis is defined as the collapse of the lungs due to which the transfer of gases from the alveoli is partially or completely stopped. When the excess fluid is filled in the pleural cavity, it will put the pressure on the walls of the lungs and drive out the gases from the lungs. Without any gas, the lungs will collapse.

Atelectasis due to pleural effusion can be diagnosed with chest X-ray. For checking the infection in the pleural cavity, thoracentesis is done to take out the fluid and analyzed in the laboratory. The treatment is done by managing the obstruction due to which the level of fluid had increased. In some cases, surgery is required to remove the fluid. Both the pleural cavities are not connected to each other. So, if there is a pleural effusion on one side, the other lung will perform a normal function. However, the condition involving both the lungs is serious and requires immediate medical intervention.

Causes of Atelectasis

Various mechanisms are proposed to determine the reasons for atelectasis. Following are the various reasons due to which a patient may experience atelectasis:

  1. Obstruction: If there is any obstruction in the bronchioles, due to mucus secretion or due to bleeding, this may lead to atelectasis.
  2. Surgery: Atelectasis in the surgeries of the chest and abdomen are one of the major causes of atelectasis. This may be due to nervous dysfunction and breaching of the chest wall.
  3. Infection: Infection may cause a reflex nervous stimulus, which may lead to atelectasis.
  4. Injury: Any injury, leading to the damage of respiratory muscles may cause atelectasis.
  5. Pleural Effusion: Pleural effusion is the excess fluid in the pleural cavity. This will increase the pressure of the lungs and the lungs may collapse.
  6. Surfactant: Surfactant is the chemicals present naturally in the lungs to keep the size intact. Any deficiency of the surfactant may cause atelectasis.


Atelectasis is the condition in which lungs gets collapsed and the function of interexchange of gases is partially or completely stopped. This may be caused due to variety of reasons such as obstruction, infection and injury. Another important reason for atelectasis is the pleural effusion. The pleural cavity is filled with excess fluid, which removes the gases from the lungs by creating pressure on the lungs. Thus, without any air inside them, the lungs collapse. The pleural effusion can be diagnosed with a chest X-ray. The treatment of atelectasis includes the exercise, which includes incentive spirometry. Further, the patient may also be put on the mechanical ventilation to support breathing.

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Pramod Kerkar, M.D., FFARCSI, DA
Pramod Kerkar, M.D., FFARCSI, DA
Written, Edited or Reviewed By: Pramod Kerkar, M.D., FFARCSI, DA Pain Assist Inc. This article does not provide medical advice. See disclaimer
Last Modified On:October 9, 2018

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