Anatomic and Manometric Abnormalities in Patients With and Without Cough

Introduction: Many patients with refractory chronic cough have co-existing swallowing disorders. Vagal dysfunction has been suggested as a basis for this relationship. In this study, we examine the link between chronic cough and vagal hypersensitivity by measuring baseline esophageal motility, focused on the upper esophageal sphincter (UES). We hypothesize that patients with chronic cough will have altered UES function relative to non-cough controls.

Methods: A cohort study was conducted with 48 patients undergoing workup for dysphagia at an academic center from April 2017 to January 2022. Patients were assigned to chronic cough or control group based on self-reported symptoms (Cough Severity Index score greater than 0). All patients underwent high resolution esophageal manometry. Differences in gender, age, race/ethnicity, medical comorbidities, laryngostroboscopy, and manometry findings were obtained retrospectively.

Results: 62.5% of our cohort had chronic cough (30/48). There were no significant differences between the two groups with respect to sex (67% female), age (mean 62±12 years) and race/ethnicity (75% White, 16.7% Hispanic). Subjects in the chronic cough group had significantly higher rates of diabetes (OR = 8.20, p = 0.04) and hypertension (OR = 3.79, p = 0.03). Laryngostroboscopy showed similar rates of vocal fold paresis in both groups, with higher rates of bilateral true vocal fold edema (60%, p = 0.16) and mild phase asymmetry (53%, p = 0.55) in the chronic cough group. Cough subjects had UES relaxation duration (734 ms) longer than the non-cough patients (582 ms; p = 0.03), though both groups had similar upper esophageal mean basal pressure, mean residual pressure, relaxation time-to-nadir, and recovery time. Median intrabolus pressure and upper esophageal motility mean peak pressure were lower in the cough group, though not statistically significant.

Conclusions: UES manometric measurement differences between subjects with and without chronic cough suggest, in line with previous studies, that vagal dysfunction in chronic cough may manifest in baseline alterations of UES relaxation.