Swyer-James syndrome (SJS) was first reported by Swyer and James in 1953 in a 6-year-old child. In 1954, Macleod reported 9 consecutive cases, so it is also known as Swyer-James-Macleod syndrome or Macleod syndrome. It is also known as unilateral hyaline lung, unilateral translucent lung or unilateral acquired lobar emphysema.
X-ray features include increased lung translucency, reduced pulmonary vascular texture, reduced or normal lung volume, and gas trapping in the expiratory phase.
The etiology of the disease was initially thought to be related to congenital development, but this was soon dismissed because there was no abnormality in the grading of the trachea or the number of branches of the pulmonary vessels. It is now believed that SJS is essentially an occlusive bronchiectasis caused by infection. Severe pulmonary infections in infancy and early childhood are the cause of the disease. Adenovirus, measles, mycoplasma, pertussis, tuberculosis, and influenza virus are the etiologic agents.
Air retention and hypoperfusion in the affected lung lobes due to occlusive bronchitis are the transparent pulmonary causes of radiological manifestations of SJS
SJS is more common in children and more common in women. The left lung is more common than the right lung. It usually involves only one or a single lobe of the lung, but can also involve multiple lobes, segments and contralateral lungs, and can be associated with other interstitial lesions. The possible causes are the same infection in infancy leading to different outcomes such as SJS caused by occlusive bronchiectasis in one site and bronchiectasis and atelectasis in another.
The main clinical manifestations of SJS are recurrent cough, sputum, hemoptysis, wheezing, and dyspnea. Most of the symptoms are related to the combination of bronchiectasis. The symptoms are less severe in those without or with columnar branch enlargement than in those with cystic branch enlargement.
Radiological imaging is used to confirm the diagnosis of SJS. Typical findings include:
(1) Increased translucency and reduced texture (but not disappearance) in the affected lung, mostly with reduced lung volume;
(2) Gas retention in the expiratory phase;
(3) Smaller pulmonary arteries;
④Interstitial lesions such as branched dilatation, atelectasis, cavitation, and subpleural infiltration may be combined.
SJS bronchoscopy showed no abnormal airway structure and no obstruction in the airway. Ventilation-perfusion scan showed decreased ventilation on the affected side and significantly decreased perfusion (suggesting smaller pulmonary arteries). Pulmonary angiography shows a small pulmonary artery trunk and branches
Differential diagnosis.
Congenital lobar emphysema with onset within 6 months of birth and progressive dyspnea and cyanosis shortly after birth, with abnormally high translucency in the affected lung field, hyperinflation of the lung lobes, shift of the mediastinal cardiac shadow to the healthy side, mediastinal lung herniation, marked compression of the adjacent lung tissue, and thin and sparse distribution of the affected lung texture.
Congenital hypoplasia of one pulmonary artery is similar to unilateral hyaline lung, but there is no history of recurrent pulmonary infections, no bronchopulmonary inflammatory changes and no signs of alveolar gas retention, and angiography shows hypoplasia of pulmonary artery or cardiovascular malformation.
Bronchial foreign bodies
Treatment and prognosis.
Prevention and control of recurrent respiratory infections with antibiotics; oral or nebulized tracheal dilators in cases of significant airway obstruction and sputum
The prognosis of SJS is related to the combination of bronchiectasis. The prognosis is good if there is no bronchial dilatation or columnar dilatation, and there is a tendency for spontaneous improvement if there is only mild respiratory symptoms without bronchial dilatation.
The indications for surgery are limited to limited branched enlargement combined with
(i) uncontrolled hemoptysis;
(ii) recurrent hemoptysis;
(iii) recurrent pulmonary infections;
(iv) other disabling symptoms