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For further information, see CMDT Part 9-17: Right Middle Lobe Syndrome

Key Features

  • Recurrent or persistent atelectasis of the right middle lobe

  • Related to the relatively long length and narrow diameter of the right middle lobe bronchus and its oval opening to the lobe

  • Important to exclude obstructing lesion such as bronchogenic carcinoma

Clinical Findings

  • Recurrent or slowly resolving right middle lobe pneumonia


  • Radiographic finding of recurrent atelectasis of right middle lobe

  • CT scan or bronchoscopy is often necessary to rule out obstructing tumor

  • Foreign body aspiration or other benign causes of atelectasis must be excluded


  • Treatment is of the underlying condition

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