The tree-in-bud sign is a relatively new yet increasingly popular finding on chest CT. Tree-in-bud refers to radiographic opacification of usually invisible small, peripheral airways that typically results from infection. While multiple diseases have been associated with the tree-in-bud finding, no study to date has examined the yield of BAL in patients with this radiographic sign. We investigated BAL results in patients with tree-in-bud sign on CT of the chest.
We retrospectively reviewed radiograph reports of every adult patient who underwent fiberoptic bronchoscopy (FB) with BAL at the University of Arizona from January 1, 2001 through December 31, 2003. The BAL results of each patient with tree-in-bud sign were reviewed, as were the treatment plans instituted based on these results. Major comorbidities in this population were recorded.
Five hundred BALs were performed during the study period. 24 patients had tree-in-bud sign on pre-FB CT scan. Eight of the 24 patients had bronchiectasis. Nine patients were immunosuppressed: diabetes (4), HIV/AIDS (1), collagen vascular disease (1), vasculitis (1), solid organ transplant (1), chemotherapy (1). Seventeen of the 24 patients (71%) had microorganisms isolated by BAL. Antibiotics were instituted based on BAL findings in 15 (62.5%). Mycobacteria were the most common organisms isolated: Mycobacterium avium-intracellulare (7), Mycobacterium tuberculosis (2), and Mycobacterium bovis (1). Fungal organisms were isolated in 3 patients: Scedosporium apiospermum (2) and coccidioidomycosis (1). Bacteria were isolated in 5 patients: Haemophilus influenzae (2), Burkholderia cepacia (1), mucoid pseudomonas (1), and Nocardia abscessus (1). Viruses were isolated in 3 patients: rhinovirus (1), cytomegalovirus (1), and parainfluenza virus type 3 (1).
BAL is associated with a high recovery rate of microorganisms in patients with tree-in-bud sign. Bronchiectasis and immunosuppression were common in the study population.
Fiberoptic bronchoscopy with BAL is effective for the diagnosis of infection in patients with tree-in-bud sign on CT scan of the chest.
R.A. Barbee, None.