Correct!

5. All of the above

Groundglass opactities are nonspecific and the differential is large including acute process such as pulmonary edema, infectious pneumonitis, and noninfectious pneumonitis. Chronic process may also present with groundglass opacities including interstitial diseases, bronchoalveolar carcinoma and numerous other causes such as organizing pneumonia, alveolar proteinosis and  chronic eosinophilic pneumonia.

Hospital Course
She was empirically started on broad spectrum antibioitics. Cocci serology and PCR of a nasal swab for influenza and mycoplasma antibodies were negative. Because no diagnosis was apparent, bronchoscopy with bronchoalveolar lavage (BAL) was done. The fluid was slightly hemorrhagic and did not clear with repeated lavage. Smears and cultures of the BAL fluid were negative. The BAL fluid was also negative for Aspergillus antibody and PCR for pneumocystis and legionella.

The patient continued to have low-grade fever  and oxygen requirements increased. For this reason a VATS lung biopsy was performed. The results  are present in Figure 2. Special stains for organisms were all negative.

Figure 2. Low power views (Panels A & B) and high power view (Panel C) of  H&E stained VATS lung biopsy. The biopsy was described as fibrinous acute lung injury with increased alveolar macrophages, scattered multinucleated giant cells and increased extravascular tissue eosinophils. 

Which of the following are consistent with the clinical course and lung biopsy?