Based on the patient’s history of asthma, physical examination, and radiograph findings, a diagnosis of right middle lung collapse was determined. Right middle lobe syndrome (RMLS) refers to chronic or recurrent atelectasis in the right middle lobe and can stem from numerous etiologies. It is characterized by wedge-shaped density that extends anteriorly and inferiorly from the hilum of the lung. Atelectasis typically occurs in the right middle lobe, but the lingula may be involved as well.
Asthma may predispose patients to atelectasis, resulting from bronchial inflammation that produces cellular debris, mucus plugs, and edema. Children are also more prone to developing atelectasis than adults because of smaller and more collapsible airways, among other features.
Lateral chest radiography is the most effective imaging technique in patients presenting with RMLS, revealing the condition's hallmark findings: a loss of volume in the right middle lobe and a blurred right heart border.
For appropriate treatment, a precise diagnosis of the pathology underlying the RMLS must be determined. This case represents a complication of uncontrolled asthma. The cornerstone of therapy is chest physical therapy and postural drainage, and the addition of mucolytics and dornase alfa may further clear airways. Children with asthma should be treated with aggressive anti-inflammatory therapy such as inhaled steroids, and the clinician may consider the addition of systemic steroids.
Cases of RMLS involving neoplastic origin or bronchiectasis should be given special consideration. Diagnosis can be confirmed with high-resolution chest CT scanning, which is safer for younger patients or those with asthma than traditional bronchography.
If a patient’s symptoms are not responsive to therapy or if the patient has predisposition to airway colonization, the clinician should perform a bronchoalveolar lavage culture to determine an appropriate antibiotic. In children with asthma, there is an association between right middle lobe collapse and infection.
Long-term follow-up has demonstrated that with treatment, RMLS typically resolves within 90 days. Soyer and colleagues also determined that baseline treatment of asthma with anti-inflammatory medications can accelerate the resolution of atelectasis. However, recurrent infections may cause parenchymal damage and bronchiectasis.
Zab Mosenifar, MD, Medical Director, Women's Lung Institute; Executive Vice Chairman, Department of Medicine, Cedars Sinai Medical Center, Los Angeles, California.
Zab Mosenifar, MD, has disclosed no relevant financial relationships.