Today’s radiographs belong to a 27-year-old with dyspnea.
1. Giant bulla
3. Loculated pneumothorax
4. Any of the above
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Findings: PA radiograph shows overinflation of the lower right lung pushing the minor fissure upward (A, arrow), simulating partial RUL collapse. In the lateral view there is a circular line (B, red arrows) suggesting the wall of a giant bulla. The correct diagnosis is made by detecting overinflation of the left lower lung and scarce vascularity, an indication that we are not dealing with localized disease of RLL (giant bulla or pneumothorax) but with disease of both lower lobes. Therefore the correct diagnosis should be 3. Emphysema.
Another finding in favor of emphysema of lower lobes is redistribution of the pulmonary circulation in which the diameter of the vessels of upper lobes (B) is larger than those of the lower lobes (C).
Pulmonary vascular redistribution is usually due to cardiac failure but it may also occur in emphysema of lower lobes in which vascular flow is redirected to the functioning upper lobes.
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Unenhanced axial CT confirm the relative sparing of upper lobes (D) and the severe emphysematous changes of lower lobes (E).
Coronal CT (F) shows severe emphysema of lower lobes and increased vascularity of upper lobes as well as discrete bronchial dilatations. Sagittal reconstruction demonstrates that the apparent wall of a bulla seen in the lateral chest radiograph represents the minor and major fissures (G, arrows) limiting a markedly emphysematous right middle lobe.
Diagnosis: Pulmonary emphysema secondary to alpha 1 antitrypsin deficiency.
This condition affects young persons and causes severe emphysema of lower lobes and bronchial dilatations.
I am showing this case because is a good example of satisfaction of search (missing changes of the left lower lobe will lead you to the wrong diagnosis).
It is also a nice example of vascular redistribution secondary to pulmonary disease.