Noninfectious Generalized Bronchiolitis in the Setting of Allogeneic Stem Cell Transplantation: A Potential Mimic of Lower Respiratory Tract Infection.
OBJECTIVE
To describe a little-known therapy-related small-airway phenomenon presumably caused by mucosal irritation in patients undergoing allogeneic stem cell transplantation (allo-SCT).


METHODS
Retrospective database search at our institution identified 739 hematologic patients who underwent chemotherapy + allo-SCT between September 2004 and March 2014. After infectious pulmonary complications were excluded, 75 patients (female = 24; male = 51; median age = 47 years) with signs of generalized bronchiolitis (GB) on chest high-resolution computed tomography were identified. Computed tomography (CT) was performed proximate to chemotherapy onset; 92% had follow-up CT (mean, 1.9 weeks). The presence of centrilobular nodules, bronchial wall thickening (BWT), tree-in-bud (distributed diffuse vs. focal), ground-glass opacity, airspace opacification, luminal impactions, and air trapping was correlated with occurrence and duration of oral mucositis and therapy characteristics. Intensity of tree-in-bud and centrilobular nodules was graded absent (grade = 0), moderate (grade = 1), or marked (grade = 2).


RESULTS
Overall incidence of GB among allo-SCT patients was 10.14%. GB was diagnosed at the time point of transplantation with a mean duration of CT findings of 4 weeks (±2.7). Tree-in-bud (17% [grade 2] and 83% [grade 1]) and BWT were present in 100% of the patients. Centrilobular nodules diffusely distributed were found in 45.5% of patients (20% [grade 2], 24% [grade 1], and 56% [none]). Air trapping and mosaic pattern were found in 13% and 16% of the patients, respectively. Resolution of GB was spontaneous. GB and its severity correlated with the temporal course and grade of oral mucositis; frequency and degree were not significantly influenced by the chemotherapy regimen. The incidence of GB in high-resolution computed tomography was statistically and significantly higher in patients with oral mucositis (P < 0.035).


CONCLUSIONS
GB is frequent during chemotherapy for allo-SCT and is characterized by an even distribution of tree-in-bud, BWT, centrilobular nodules, mild clinical symptoms, and spontaneous resolution.
Department of Diagnostic and Interventional Radiology, Eberhard-Karls-University, Hoppe-Seyler-Str. 3, 72076 Tübingen, Germany. Electronic address: christopher.kloth@med.uni-tuebingen.de.
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C
Kloth
Department of Diagnostic and Interventional Radiology, Eberhard-Karls-University, Hoppe-Seyler-Str. 3, 72076 Tübingen, Germany.
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U
Grosse
Department of Internal Medicine II, Eberhard-Karls-University,72076 Tübingen, Germany.
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Wirths
Department of Diagnostic and Interventional Radiology, Eberhard-Karls-University, Hoppe-Seyler-Str. 3, 72076 Tübingen, Germany.
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Gatidis
Department of Internal Medicine II, Eberhard-Karls-University,72076 Tübingen, Germany.
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Bethge
Department of Diagnostic and Interventional Radiology, Eberhard-Karls-University, Hoppe-Seyler-Str. 3, 72076 Tübingen, Germany.
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Nikolaou
Department of Diagnostic and Interventional Radiology, Eberhard-Karls-University, Hoppe-Seyler-Str. 3, 72076 Tübingen, Germany.
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Horger
D000328:Adult; D000368:Aged; D001988:Bronchiolitis / Q000139:chemically induced / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D005260:Female; D006402:Hematologic Diseases / Q000628:therapy; D018380:Hematopoietic Stem Cell Transplantation / Q000009:adverse effects*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012141:Respiratory Tract Infections / Q000000981:diagnostic imaging; D012189:Retrospective Studies; D013280:Stomatitis / Q000139:chemically induced / Q000453:epidemiology*; D014057:Tomography, X-Ray Computed; D019172:Transplantation Conditioning / Q000009:adverse effects* / Q000379:methods; D014184:Transplantation, Homologous / Q000009:adverse effects; D055815:Young Adult
Allogeneic stem cell transplantation (allo-SCT); Generalized bronchiolitis; HRCT; Mucositis