Cough receptor sensitivity and bronchial responsiveness in patients with only chronic nonproductive cough: in view of effect of bronchodilator therapy.
Twenty-two patients with only chronic nonproductive cough lasting for more than 2 months were prospectively examined to determine whether airway cough receptor sensitivity and bronchial responsiveness relate to the efficacy of bronchodilator therapy on the cough. Clenbuterol (10 micrograms, 4 times a day for 1 week) was effective on the cough in 10 patients (group 2) but not in the other 12 patients (group 1). Cough threshold to inhaled capsaicin was significantly less in group 1 than in group 2 at the first visit but not after the therapy when the cough stopped. Bronchial responsiveness to methacholine (PC20-FEV1) was not heightened in group 1, while that in group 2 was hyperreactive. These findings suggest that nonproductive cough is elicited based on two different mechanisms: (1) heightened airway cough receptor sensitivity in bronchodilator-resistant cough and (2) bronchoconstriction in bronchodilator-responsive cough such as cough-variant asthma.
Third Department of Internal Medicine, Kanazawa University School of Medicine, Japan.
M
M
Fujimura
Y
Y
Kamio
T
T
Hashimoto
T
T
Matsuda
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016535:Bronchial Hyperreactivity / Q000188:drug therapy; D001985:Bronchial Provocation Tests; D001993:Bronchodilator Agents / Q000627:therapeutic use*; D002211:Capsaicin; D002908:Chronic Disease; D002976:Clenbuterol / Q000627:therapeutic use*; D003371:Cough / Q000139:chemically induced / Q000188:drug therapy*; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D008297:Male; D016210:Methacholine Chloride; D008875:Middle Aged; D011446:Prospective Studies; D012129:Respiratory Function Tests; D011984:Sensory Receptor Cells / Q000187:drug effects*; D013183:Sputum / Q000382:microbiology
D001993:Bronchodilator Agents; D016210:Methacholine Chloride; D002211:Capsaicin; D002976:Clenbuterol