Respiratory bronchiolitis associated with severe dyspnea, exertional hypoxemia, and clubbing

Respiratory bronchiolitis-associated interstitial lung disease (RBILD) is a distinct clinicopathologic disease described almost exclusively in cigaret te smokers.(1,2) The disease usually presents with mild symptoms and is ass ociated with a good prognosis.(2) Severe lung dysfunction has not been repo rted with RBILD, which is often confused clinically and radiographically wi th desquamative interstitial lung disease or idiopathic pulmonary fibrosis (IPF), Two patients with RBILD who del-eloped severe dyspnea, hypoxemia, an d clubbing are described. Initially, IPF was diagnosed in both patients. Th e severity of symptoms was such that the first patient's room air saturatio n was 85% and the second patient had severe impairment of lung function, wi th FEV1 of 39% and FVC of 40%. Advanced lung disease required supplemental home oxygen therapy in the first patient and referral for lung transplant e valuation in the second patient. After a detailed review of histology revea led a diagnosis of RBILD, both patients were encouraged to stop smoking; sm oking cessation led to considerable improvement in symptoms and lung functi on tests. We conclude that advanced lung dysfunction occurs in some patient s with RBILD and should not dissuade that diagnosis.