[The distal airways in systemic disease]

The association of inflammatory involvement of the distal airways or bronchiolitis and systemic diseases is essentially observed in Sjögren's syndrome, rheumatoid arthritis and chronic inflammatory bowel disease. Bronchiolitis may be mainly cellular in nature, often involving lympho-monocytic cells, and sometimes associated with lymphoid follicles, as in Sjögren's syndrome. It may also, particularly in rheumatoid arthritis, be constrictive, with peribronchiolar fibrosis. This type is associated with a worse prognosis, with possible progression to chronic respiratory insufficiency. The diagnosis of bronchiolitis should be suspected in any atypical form of asthma, or recurrent "bronchitis", and it is essential to look for extrarespiratory symptoms and auto-antibodies to establish the diagnose of systemic disease. The CT appearances coupled with the evaluation of pulmonary function parameters usually lead to the diagnosis. In severe and/or rapidly progressive cases treatment-combining corticosteroids with immunosuppressive drugs may be prescribed, but often with disappointing results. In these cases, lung transplantation should be considered in young patients.