Extrathoracic airway dysfunction in cough associated with gastroesophageal reflux

Abstract Background: Cough associated with gastroesophageal reflux (GER) may originate in extrathoracic airway receptors made hypersensitive by acid-induced mucosal injury. Objective: We investigated the role of laryngeal disease and dysfunction in the pathogenesis of GER-associated cough in nonasthmatic patients. Methods: Seven patients with GER-associated cough were compared with 7 patients with GER but no cough. The patients underwent fiberoptic endoscopy for assessment of laryngitis and esophagitis (expressed by scores); esophageal manometry; 24-hour pH monitoring; lung function tests; and histamine inhalation challenge with assessment of bronchial threshold (concentration provoking 10% fall in FEV 1 [PC 10 ]), extrathoracic airway threshold (concentration provoking 25% fall in the maximal midinspiratory flow [PC 25 MIF 50 ]), and cough threshold (concentration provoking 5 or more coughs PC cough ). The patients were reevaluated after 3 months of medical treatment for GER. Results: Patients with cough, compared with those without cough, had significantly higher laryngitis scores ( P = .002), lower esophageal sphincter pressures, longer time with pH below 4 ( P = .003), greater number of episodes of reflux longer than 5 minutes ( P = .016), longer esophageal clearance time ( P = .048), and significantly lower PC 25 MIF 50 ( P = .005) and PC cough ( P = .008) values. Laryngitis score was significantly inversely related to either PC cough ( P 25 MIF 50 ( P 10 . Laryngitis score, PC 25 MIF 50 , and PC cough were all closely related to GER severity. After GER treatment, laryngitis, PC 25 MIF 50 , and PC cough were all significantly improved. Conclusions: These findings suggest that GER-associated cough is strongly associated with laryngeal disease and dysfunction consequent to acid reflux injury in nonasthmatic patients. (J Allergy Clin Immunol 1998;102:204-9)