Correct!
2. Hypersensitivity pneumonitis
The presence of multifocal ground-glass opacity with features of small airway obstruction is a pattern associated with, though not absolutely specific for, hypersensitivity pneumonitis; this pattern of infiltrative and obstructive pulmonary abnormalities on the same inspiratory scan image has been referred to as the “headcheese” sign. Diffuse alveolar hemorrhage is also a consideration for multifocal ground-glass opacity, but would not explain the conspicuous feature of lobular low attenuation, which suggests small airway obstruction. The imaging appearance is not suggestive of sarcoidosis, which more commonly presents with symmetric peribronchial and mediastinal lymph node enlargement, perilymphatic nodules, and/or upper lobe fibrotic disease/opportunistic infection can present with multifocal ground-glass opacity- particularly Pneumocystis jirovecii pneumonia- but the patient is not immunocompromised, which makes this infection, and other opportunistic infections, very unlikely. Organizing pneumonia is a consideration, but typically manifests as multifocal consolidation, possibly some ground-glass opacity, distributed in the peripheral or frankly subpleural regions of lung or along the bronchovascular bundles; additionally, organizing pneumonia may present with the “atoll” or “reverse [ground-glass] halo” sign. In this case, however, the opacities are multifocal, or nearly diffuse, in distribution, and do not show a peripheral or peribronchial distribution, and are therefore not directly suggestive of organizing pneumonia.
At this point, which of the following courses of action is the most appropriate next step for the management of this patient? (Click on the correct answer to be directed to the eleventh of fourteen pages)