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  • • Relapsing lateral pneumonia of right middle pulmonary lobe (RML) caused by intermittent obstruction

    • Obstruction most often extrinsic

    • Consider diagnosis with repeated right-sided pneumonia

    • May be caused by compression/erosion of bronchus by adjacent diseased lymph nodes

    • Poor natural drainage and lack of collateral ventilation explain frequency of involvement of RML

Symptoms and Signs

  • • Repeated right-sided pneumonias

Rule Out

  • • Other causes of obstruction (neoplasm, foreign body)

  • • Bronchoscopy to rule out endobronchial tumors and foreign bodies

  • • Intensive medical therapy usually adequate treatment


  • • RML lobectomy


  • • Bronchiectasis

    • Fibrosis of RML

    • RML abscess

    • Intractable recurrent pneumonia

    • Suspicion of neoplasm


Ring-Mrozik E et al. Clinical findings in middle lobe syndrome and other processes of pulmonary shrinkage in children (atelectasis syndrome). Eur J Pediatr Surg. 1991;1:266.  [PubMed: 1747357]

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