Refractory/unexplained cough (RUCC) is typically associated with throat symptoms and a dry cough. Some patients attending specialist cough clinics however, report sputum production (>1 tablespoon daily) and atypical sensations (urge-to-cough in chest). Bronchoscopy findings in this specific cohort have rarely been described.

We aimed to evaluate bronchoscopy, bronchoalveolar lavage (BAL) cell differential and microbiology findings in RUCC with mucus production.

We retrospectively reviewed case notes, procedure results and treatment of patients undergoing bronchoscopy for RUCC with more than a tablespoon of sputum daily.

Data were included from 54 patients with RUCC, normal or trivial findings on CT (Computerised Tomography) imaging and no response to guideline-directed treatment of their cough. Most (84%) patients had BAL neutrophilia and excessive dynamic airway collapse (EDAC) was seen in 31%. Treatment strategies in these patients differed to those adopted in typical RUCC associated with a dry cough. Management was influenced or changed in 48/54 (89%) of the patients undergoing bronchoscopy. Conclusions: Bronchoscopy provides high diagnostic value in RUCC with mucus production (>1 tbsp daily), identifying specific treatable traits including neutrophilic airway inflammation and EDAC.