Atelectasis is the condition wherein the lungs get collapsed due to various reasons and the lungs are unable to perform the function of exchange of gases in an efficient manner. There are various areas of the lungs where atelectasis may occur. One of the atelectasis which is chronic or recurrent and occurs in the right middle lobe of the lungs is known as Right Middle Lobe Syndrome (MLS). The diagnosis is done with the help of chest radiography in which the lung is seen from the lateral side. There are generally two types of right MLS (atelectasis in the right middle lobe), Obstructive and non-obstructive. The obstructive right MLS `develops due to the obstruction of mucus or tumor in the region. In contrast to above, the non-obstructive right MLS (atelectasis in the right middle lobe) does not show any obstruction and the reasons for this right MLS are not well known. The proposed reasons may be infection or inflammation in the right middle lobe. It occurs in the patients, especially children, who are suffering from asthma or other respiratory diseases.


Symptoms Of Atelectasis In The Right Middle Lobe

Atelectasis in the right middle lobe is diagnosed as a wedge-shaped density which is visible in the X-ray, when taken from the lateral side of the lungs. Right MLS is more prominent in females as compared to males. In very rare cases, the right MLS exists without any symptoms and the condition is diagnosed. Following are the symptoms experienced by the patients suffering from right MLS:


  • Chronic or recurrent cough present in the majority of the patients.
  • Dyspnea
  • Chest pain
  • Recurrent fever and chills
  • Weight loss and fatigue are other complications of right MLS.
  • Bronchiectasis

Pathophysiology Of Atelectasis In The Right Middle Lobe

The atelectasis in the right middle lobe can be caused due to various reasons and on the basis of the reason; it can be divided in to obstructive right MLS and non-obstructive right MLS. In the obstructive MLS (atelectasis in the right middle lobe), mucus or foreign objects obstruct the lobar bronchus leading to middle lobe syndrome. The pathophysiology of the non-obstructive right MLS (atelectasis in the right middle lobe) is not well understood and is a complex phenomenon. It can be caused due to abnormal anatomical structure and makes the lobe susceptible to collapse during inflammation or edema. Further, the angle created due to abnormal anatomical structure may lead to poor drainage. MLS is also caused by secondary changes due to bronchitis and pneumonitis. The children are generally more susceptible to the asthma associated inflammation leading to right MLS. The right MLS may also develop due to the compression of the middle lobe bronchus by the lymph nodes. Further, an important reason for the MLS is the separation of the middle lobe from the upper and the lower lobe and a lack of collateral ventilation.


Treatment For Atelectasis In The Right Middle Lobe

The treatment is divided into two parts depending upon the severity of the condition and the responsiveness of the treatment.

  1. Treatment With Drugs And Medical Care: The drugs are used for the treatment of atelectasis in the right middle lobe along with the chest physiotherapy. The postural drainage and the chest therapy are generally done to relive the symptoms of atelectasis in the right middle lobe. Further, the drugs used in the therapy are bronchodilators, mucolytics and the antibiotics are used when the reason for right MLS is infection. In children, the treatment is aggressively done with the help of steroids. The chest wall oscillation devices are also used to support the main therapy. The patients with severe infection should be treated aggressively by administering the potent and broad spectrum antibiotics. Further, the patients are also treated with non-invasive techniques such as air insufflation through bronchoscopy.
  2. Surgical Intervention: The other method of treating atelectasis in the right middle lobe is the surgery. When the patient is unresponsive to the drug therapy then the surgical intervention is required. Surgery may include lobectomy and bronchography. The common complication associated with surgery includes bleed and air leakage.


Right middle lobe syndrome is defined as the collapse of the right middle lobe. The reason for this may be obstructive or non-obstructive. The obstruction may be due to mucus or foreign substance and the Non-obstructive right MLS is generally due to anatomical defect. The treatment is through drugs or surgery. Drugs used are bronchodilators and mucolytic agents and the treatment is supported by physical techniques. Surgical methods include lobectomy and bronchography.

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Pramod Kerkar

Written, Edited or Reviewed By:


Pain Assist Inc.

Last Modified On: October 5, 2018

This article does not provide medical advice. See disclaimer


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