Infectious bronchiolitis refers to subtype of bronchiolitis where there is an definite infective precipitant. It falls under the subgroup in inflammatory bronchiolitides and by some authors is considered a type of cellular bronchiolitis 3. It tends to be more clinically severe in children than adults.
It is characterized histologically by a pattern of acute bronchiolar injury, with epithelial necrosis and inflammation of the bronchiolar walls and intraluminal exudates. There can also be oedematous change and fibrosis within bronchiolar walls.
- respiratory syncytial virus (RSV): particularly in children (RSV bronchiolitis)
- bacterial species
- mycobacterial species
- Mycobacterium tuberculosis: see pulmonary manifestations of tuberculosis
- atypical mycobacterial species
- fungal species, e.g. Aspergillus fumigatus, particularly in immunocompromised patients
CT (HRCT) chest
Intense bronchiolar mural inflammation of cellular bronchiolitis results in centrilobular nodules that are usually associated with the tree-in-bud pattern 1. There can also be presence of bronchiolar wall thickening.
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