Answer to Quiz No. 19/2015 dated 05 July 2015
Swyer–James (McLeod) syndrome
Findings
Chest radiograph: Uniformly increased lucency of the left hemithorax with diffuse paucity of vascular markings in left lung. Left hilum is small. Both lung volumes are normal. CT Thorax lung window: Hyperlucent left lung with uniformly decreased vascular markings, mild reduction in left lung volume and mild cylindrical bronchiectasis. IMPRESSION: Findings likely represent post-infectious obliterative bronchiolitis or Swyer James syndrome
Discussion
Lung parenchymal causes of a unilateral hyper-transradiant hemithorax : 1. Airway obstruction with ball valve mechanism – air trapping on expiration results in increased lung volume and shift of the mediastinum to the contralateral side. It may be possible to see an intraluminal foreign body obstructing the bronchus. 2. Congenital lobar emphysema – Marked overinflation of a lobe (most commonly left upper lobe followed by right upper lobe or right middle lobe). The ipsilateral lobes are compressed and there may be mediastinal displacement to the contralateral side. 3. Compensatory hyperexpansion – - post lobectomy (look for rib defects or surgical sutures / staples indicating previous surgery) - lobar collapse (on left side, look for retrocardiac opacity which may indicate left lower lobe collapse) 4. Unilateral bullae – usually does not involve the entire hemithorax. There is paucity of lung markings in the affected portion of the lung 5. Swyer–James (McLeod) syndrome – Late sequel of infectious obstructive bronchiolitis in childhood (commonly adenovirus). Chest radiograph: Lung volume on affected side is normal or slightly reduced and there is air trapping on expiration. Ipsilateral hilar vessels are small. CT: Affected lung is hyperlucent with decreased vascularity. The size of the majority of the affected lobes are smaller although occasionally they can be normal. Bronchiectasis may be present Vascular causes like chronic pulmonary embolism / vasculitis or central mass causing narrowing of the pulmonary arteries also has to be excluded before making a diagnosis of Swyer James syndrome.
References
1. Zylak CJ, Eyler WR, Spizarny DL et-al. Developmental lung anomalies in the adult: radiologic-pathologic correlation. Radiographics. 2002;22 Spec No : S25-43.
2. Chapman & Nakielnys Aids to Radiological Differential Diagnosis, ed. 6A
Contributed By:
Dr Reettika Chanda, Dr Aparna Shyam, Christian Medical College, Vellore
Findings
Chest radiograph: Uniformly increased lucency of the left hemithorax with diffuse paucity of vascular markings in left lung. Left hilum is small. Both lung volumes are normal. CT Thorax lung window: Hyperlucent left lung with uniformly decreased vascular markings, mild reduction in left lung volume and mild cylindrical bronchiectasis. IMPRESSION: Findings likely represent post-infectious obliterative bronchiolitis or Swyer James syndrome
Discussion
Lung parenchymal causes of a unilateral hyper-transradiant hemithorax : 1. Airway obstruction with ball valve mechanism – air trapping on expiration results in increased lung volume and shift of the mediastinum to the contralateral side. It may be possible to see an intraluminal foreign body obstructing the bronchus. 2. Congenital lobar emphysema – Marked overinflation of a lobe (most commonly left upper lobe followed by right upper lobe or right middle lobe). The ipsilateral lobes are compressed and there may be mediastinal displacement to the contralateral side. 3. Compensatory hyperexpansion – - post lobectomy (look for rib defects or surgical sutures / staples indicating previous surgery) - lobar collapse (on left side, look for retrocardiac opacity which may indicate left lower lobe collapse) 4. Unilateral bullae – usually does not involve the entire hemithorax. There is paucity of lung markings in the affected portion of the lung 5. Swyer–James (McLeod) syndrome – Late sequel of infectious obstructive bronchiolitis in childhood (commonly adenovirus). Chest radiograph: Lung volume on affected side is normal or slightly reduced and there is air trapping on expiration. Ipsilateral hilar vessels are small. CT: Affected lung is hyperlucent with decreased vascularity. The size of the majority of the affected lobes are smaller although occasionally they can be normal. Bronchiectasis may be present Vascular causes like chronic pulmonary embolism / vasculitis or central mass causing narrowing of the pulmonary arteries also has to be excluded before making a diagnosis of Swyer James syndrome.
References
1. Zylak CJ, Eyler WR, Spizarny DL et-al. Developmental lung anomalies in the adult: radiologic-pathologic correlation. Radiographics. 2002;22 Spec No : S25-43.
2. Chapman & Nakielnys Aids to Radiological Differential Diagnosis, ed. 6A
Contributed By:
Dr Reettika Chanda, Dr Aparna Shyam, Christian Medical College, Vellore
