Right middle lobe syndrome in children.

Right middle lobe syndrome (RMLS) is characterized by a spectrum of diseases from recurrent atelectasis and pneumonitis to bronchiectasis of the middle lobe. It has been described among all age groups, although the diagnosis in pediatrics may be delayed or missed because of non-specific symptoms or findings. Twenty-one children with RMLS were evaluated during the past 10 years with particular attention to the history, bronchoscopic and pathologic findings. Most of these patients had asthma or a family history of atopic disorders; 3 patients had a family history of RMLS. Only two of the 21 patients had sufficient obstruction on bronchoscopy to account for their disease. Four had evidence of concomitant laryngeal pathology. The various theories of pathogenesis are discussed. In this series, the non-obstructive (impaired collateral ventilation) theory appeared to be most plausible. Bronchoscopy was performed in all instances to rule out obstruction due to foreign body or tumor. It was therapeutic in two-thirds of the cases. Resolution occurred promptly in one-third, and eventually in another third. Of the remaining patients, 4 required lobectomy and were cured; two have decreased but persistent symptoms. An aggressive medical management following bronchoscopy is warranted in all cases, especially when there is a possibility of asthma.