Tussive effect of capsaicin in patients with gastroesophageal reflux without cough.

Abstract

The aim of this study was to clarify the influence of gastroesophageal reflux (GER) on cough threshold in patients with digestive symptoms but free from respiratory involvement. Of 57 consecutive subjects referred for 24-h esophageal pH monitoring because of digestive reflux symptoms, 29 patients free from respiratory disorders were studied. They underwent esophageal pH monitoring and manometry, upper gastrointestinal endoscopy, pulmonary function tests, and methacholine and capsaicin challenges. The methacholine test was performed by inhalation of increasing doses of methacholine up to 4,000 micrograms; the results were expressed as the dose causing a 20% decrease in FEV1 from baseline (PD20). The capsaicin threshold was evaluated by inhalation of increasing doses of capsaicin from 0.3 up to 9.84 nmol, expressing the results as the dose of capsaicin eliciting five coughs (PD5). Fifteen patients were considered refluxers on the basis of a total esophageal acid exposure time above 4.7%. Esophagitis grade 0 was found in 15 patients, grade 1 in seven patients, grade 2 in seven patients. PD5 was significantly lower in refluxers (median 0.51 micrograms, range 0.22 to 19.8) than in nonrefluxers (19.8 micrograms, range 0.31 to 19.8) (p < 0.001); there was no difference in baseline ventilatory parameters and in airway responsiveness to methacholine between the two groups. All patients with a pathologic acid exposure time but one had a low cough threshold, irrespective of the presence or absence of esophagitis.(ABSTRACT TRUNCATED AT 250 WORDS)

Are there clinical features of a sensitized cough reflex?

“…This statement is strongly supported [50] and idiopathic pulmonary fibrosis [51]. The cough reflex is also heightened in extra-pulmonary diseases associated with cough such as gastrooesophageal reflux disease [52] and rhinosinusitis [8]. It is important to appreciate that the cough reflex is in dynamic state of activation and a number of exogenous and endogenous factors may alter the degree of sensitization.…”

Capsaicin cough receptor sensitivity test in children

“…We have also shown that it is important to standardize the IFR, a factor not considered in the clinical papers involving capsaicin [2,3]. The geometric mean was significantly affected when the IFR was not standardized; the repeatability of the test, thus, becomes irrelevant, when the IFR is not controlled.…”

“…In the assessment of patients, a clinically significant change in measurement has to lie beyond the 95% range [9]. Studies on cough receptor sensitivity in adults have described estimates of repeatability using analysis of variance [13,14] or correlation methods [6], whilst other studies using capsaicin have not included repeatability measurements for the laboratory [2,3]. In our study, we have demonstrated that the capsaicin cough challenge test is repeatable for C2, C5 and Cth, if the IFR is constant.…”

“…Capsaicin has been used as a tussive agent in studies to determine cough receptor sensitivity [1][2][3]. However, in contrast to histamine and methacholine challenges [4,5], the methodology of the capsaicin cough challenge test is not yet standardized, with different laboratories using not only different delivery methods but also different inhalation methods [2,3,[6][7][8].…”

“…However, in contrast to histamine and methacholine challenges [4,5], the methodology of the capsaicin cough challenge test is not yet standardized, with different laboratories using not only different delivery methods but also different inhalation methods [2,3,[6][7][8]. Repeatability studies using current statistical standards [9][10][11] have not been performed.…”