Das Swyer-James-MacLeod-Syndrom wird oftmals mit bronchialen Erkrankungen im frühen Kindesalter in Zusammenhang gebracht. Die Studie aus dem Jahr 2012 zeigt, dass möglicherweise auch andere Faktoren zu einem späteren Zeitpunkt ausschlaggebend sein können.
Die folgende Studie ist unverändert aus dem US National Library of Medicine, National Institutes of Health in englischer Sprache übernommen worden*. Sie dient nicht der kommerziellen Nutzung.
Abstract
Swyer-James-Macleod syndrome (SJMS) is a rare, complex disease characterised by unilateral hyperlucent lung or lobe owing to loss of pulmonary vasculature and alveolar hyperdistention. Patients with SJMS may be asymptomatic at diagnosis, but its differential diagnosis with asthma is difficult. Almost all the reported cases of SJMS were managed by conservative therapy, comprising prevention and treatment of recurrent pulmonary infections.
Background
Swyer-James-Macleod syndrome (SJMS) is a rare condition characterised by unilateral hyperlucency of a part of or the entire lung. It was first described in 1953 in a 6-year-old child,1 and a year later, nine adult cases were reported by MacLeod.2 The syndrome is thought to be secondary to bronchiolitis obliterans acquired in infancy, which results in obstruction of small airways and secondary emphysema, hypoplasia and/or agenesis of the pulmonary arteries resulting in pulmonary parenchyma hypoperfusion.Patients are usually asymptomatic but typically present with a history of recurrent episodes of pulmonary infection with onset early in life. Symptomatic patients have dyspnoea on exertion, haemoptysis and/or chronic productive cough. It is identified most commonly by chest x-ray study revealing an increased density in the lung fields of the affected side with coexistent decreased lung volumes and is frequently an incidental finding. This radiological finding, first described by MacLeod as chest x-ray ‘transradiancy’, has been termed as ‘hyperlucency’ by radiologists in the intervening years, but is not specific for the syndrome.3
Case presentation
A 40-year-old man was admitted to the hospital with dyspnoea, especially on exercise, for the past 6 months. He had a history of upper airway infections before the beginning of symptoms. He was treated for acute bronchitis with antibiotics bronchodilators and chest physiotherapy, in the last year. He has a 10 pack-year history of smoking. There was no significant problem in childhood. Chest auscultation demonstrated the decreased breath sound on the basis of left hemithorax.
Investigations
The chest radiograph on admission disclosed unilateral hyperlucency of right lower lung and decreased vascularity. CT scans revealed hyperlucency and diminished vascularity in the left lower lobe with hyperinflation of the pulmonary parenchyma (figure 1). CT scans demonstrated tubuler bronchiectasis and minimal thickening of the bronchial walls in the left-affected lower lobes (figure 2). CT also showed similar tubuler bronchiectasis in the left lung apicoposterior segment (figure 3).
Figure 1
Axial (A) and coronal (B) CT scans demonstrating hyperinflation (arrows) and diminished vascularity (arrowhead) in the pulmonary parenchyma.
Figure 2
Axial (A) and coronal (B) computed tomography scans demonstrating tubuler bronchiectasis in the left lower lobes.
Figure 3 Axial CT scan demonstrating tubuler bronchiectasis in the left lung apicoposterior segment.
Discussion
SJMS is an uncommon clinic and pathological syndrome. The disease starts as an obliterative bronchiolitis with concomitant vasculitis commonly following infections with organisms such as adenovirus, measles or pertussis. The damage to the terminal or respiratory bronchioles in early childhood possibly prevents normal development of their alveolar buds.4 The patients of SJMS may be asymptomatic, but usually present with chronic and repeated pulmonary infections, dyspnoea on exertion, haemoptysis and even severe respiratory impairment.5 6 Clinically, the disease is often an incidental finding on chest x-ray study, although patients with this syndrome have been described with dyspnoea, decreased exercise tolerance, cough, haemoptysis, failure to thrive and recurrent pulmonary infections, as well as lung abscess.7 8 Clinical findings are non-specific and may include decreased chest expansion, rales or hyper-resonance.9 Diagnosis in the past relied on typical chest x-ray findings in the absence of obstructing airway mass, pulmonary embolism or other cause for the radiological findings examined via bronchoscopy, ventilation-perfusion scans, angiography or scintigraphy. Pulmonary function test showed obstructive defection in varied degrees.5 CT scan has been shown to have a higher sensitivity for the detection of hypoplastic lung lobes, bronchiectasis and pulmonary bronchus size when compared with standard end expiratory frontal chest x-ray studies.10 Treatment of SJMS is typically conservative and supportive, including close follow-up and management of recurrent pulmonary infections, and rarely with lung resections for recalcitrant disease.Rarely, patients with SJMS are treated by lung resection for recalcitrant disease managed with chest physiotherapy for left bronchial drainage, low-dose inhaled steroid and inhaled bronchodilators.
Learning points
Swyer-James-Macleod syndrome (SJMS) is a rare disease characterised by unilateral hyperlucent lung or lobe owing to loss of pulmonary vasculature and alveolar hyperdistention.
The syndrome is thought to be secondary to bronchiolitis obliterans acquired in infancy, which results in obstruction of small airways and secondary emphysema.
The patients of SJMS are usually asymptomatic, but present with chronic and repeated pulmonary infections, dyspnoea on exertion, haemoptysis and even severe respiratory impairment.
The treatment is typically conservative and supportive.
*Copyright 2012 BMJ Publishing Group Ltd
Footnotes
Competing interests: None.
Patient consent: Obtained.
References
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