An uncommon obliterative lung disease: Swyer-James-MacLeod syndrome.

Abstract

A 42-year-old woman presented with substernal chest pain, productive cough with yellow sputum, and shortness of breath. Chest pain was present for 1 day, and worsened with deep inhalation and movement. The patient denied fever, chills, and diaphoresis. Physical examination revealed a well-appearing women in no apparent distress. Auscultation of the lungs demonstrated moderate crackles in the right lower lung, and chest examination was positive for mild tenderness to palpation along the right anterior chest wall. The remainder of the physical examination was unremarkable. A complete blood count with differential, complete metabolic panel, cardiac enzymes, and electrocardiogram were unremarkable. Anterior–posterior chest X-ray study demonstrated diminished right thoracic cage volume and diminished right lung volumes compared to the left (Fig. 1a). Computed tomography angiogram (CTA) revealed a hyperlucent right lung with diminished vascularity, and an overall reduction in right lung volume compared to the left (Fig. 1b). Ventilation–perfusion scan demonstrated matched defects. Specifically, there was decreased radioisotope uptake in the right lung on both the ventilation and perfusion images, compatible with a destructive process of the entire right lung (Fig. 1c, d). Clinical appearance and imaging supported a diagnosis of Swyer–James–MacLeod syndrome, a rare acquired obliterative lung syndrome. Swyer–James–MacLeod syndrome (SJMS) is an uncommon obliterative lung disease that is a rare complication of a lower respiratory tract infection during childhood [1]. This syndrome is most often seen in children, but can rarely present in adults with a past medical history of recurrent respiratory infections. SJMS can be caused by numerous microbes including adenovirus types 3,7, and 21, paramyxovirus morbillivirus, Bordetella pertussis, Mycoplasma pneumoniae, Mycobacterium tuberculosis, and influenza A [2, 3]. These infections can cause post-infectious bronchiolitis obliterans, and may also cause hypoplasia or agenesis of the pulmonary vasculature. In the latter scenario, hypoperfusion of the pulmonary parenchyma will result in unilateral hyperlucency of the lung on radiographic images [2, 3]. The symptoms of SJMS can vary from asymptomatic to chronic or recurring lung infections, dyspnea, or hemoptysis [1]. Pathogenesis involves inflammation of the respiratory bronchioles, leading to bronchiole wall fibrosis and concurrent narrowing of the bronchiole lumens. Fibrosis in the interalveolar septae is responsible for the destruction of the pulmonary capillary beds, which results in decreased perfusion to the pulmonary artery, leading to pulmonary artery hypoplasia [1]. Diagnosis is made following radiographic evidence (plain film and CT) of the classic SJMS triad: which includes a unilateral hyperlucent lung, diffusely decreased ventilation, and matching decreased perfusion in the affected lung [3]. Unilateral lung hypoplasia, destruction of the pulmonary parenchyma and air trapping (bronchiectasis) are also likely to be visualized on CT imaging [1, 2]. Abnormal pulmonary arterial vasculature characterized by decreased caliber may be visualized if CTA of the pulmonary vasculature is performed [2]. The treatment of SJMS is often conservative, and typically involves & Katherine M. Wojcicki Wojcickk@my.canisius.edu