Constrictive bronchiolitis presenting with a mixed obstructive and restrictive pattern, associated with acid reflux

A previously healthy 55-year-old woman presented with worsening dyspnoea on exertion. The patient lived at altitude, did not smoke and had no exposure to occupational or environmental toxins. Her physical examination, including pulmonary, was unremarkable. Pulmonary function tests showed forced expiratory volume in 1 s/forced vital capacity ratio 74% predicted, diffusing capacity for carbon monoxide (DLCO) 92% predicted and residual volume 213% predicted. Rheumatological workup was negative. Chest radiograph showed hyperinflation without consolidation, and high-resolution chest CT showed mosaic attenuation with air trapping on expiratory imaging. A decreasing DLCO lead to transbronchial biopsies that were inconclusive. A video-assisted thoracic surgery lung biopsy showed small airway disease suggestive of constrictive bronchiolitis. Oesophagram and a barium swallow showed a hiatal hernia with large volume gastro-oesophageal reflux to the level of the clavicles. The development of constrictive bronchiolitis in this patient was possibly secondary to hiatal hernia and silent gastroesophageal reflux disease (GERD). In the face of presumably idiopathic lung disease, clinicians should perform a GERD workup even in the absence of GERD symptoms.