IS Case 408: Vanishing lung syndrome
Imaging Sciences URMC 2010
Publication Date: 2010-08-27
Vanishing lung syndrome
A bullae is defined as an emphysematous space larger than 1 cm with thin or invisible wall. They are commonly subpleural and occur in the lung apex.
Idiopathic giant bullous emphysema, also known as vanishing lung syndrome, is characterized by very large bullae. The radiographic criteria for vanishing lung syndrome includes the presence of giant bullae in one or both upper lobes, occupying at least one third of the hemithorax and compressing the surrounding normal lung parenchyma.The bullae have an upper lobe predominance with varying sizes ranging from 5 to 10 cm in diameter. The distribution is usually asymmetric. The patient is commonly a young male cigarette smoker. This condition is progressive. A dominant high resolution CT feature in both smokers and nonsmokers is extensive paraseptal emphysema coalescing into giant bullae.
Since these patient present with shortness of breath, it can be difficult to evaluate for superimpose spontaneous pneumothorax clinically. In patient's with known or suspected giant bullous emphysema and in whom consideration for chest tube placement is equivocal based on clinical and conventional radiographic findings, CT would be recommended. Several signs have been used to aide detection of pneumothorax in patient's with giant bullous emphysema. The double wall sign is when air is seen outlining both sides of the bulla wall parallel to the chest wall on CT. One potential pitfall is when two large bullae are adjacent to one another, mimicking a double wall sign. Stringent scrutiny of the adjacent images are needed in this situation to show the absence of air in the pleural space. Other signs to detect pneumothorax include compressed or consolidated lung, nonanatomic hyperlucency and immediate relief and lung expansion at chest tube placement.
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