CHANGES AND IMPLICATIONS OF COUGH SENSITIVITY IN UPPER AIRWAY COUGH SYNDROME

Objective To investigate the changes and clinical implications of cough sensitivity in upper airway cough syndrome(UACS).Methods Cough threshold C5 was measured by capsaicin cough sensitivity test in 94 patients with upper airway cough syndrome;it was also measured in 30 patients after cough completely resolved with specific therapy.Results The mean cough threshold C5 was 5.85(1.95,31.2)μmol/L and within the normal range;however,36 patients(38.30%) presented cough hypersensitivity.Thirty patients received re-examination of cough sensitivity to capsaicin after cough disappeared,there was no significant difference in cough threshold C5 between pre-and post-treatment[5.85(1.95,31.2)μmol/L vs 7.8(0.98,7.8)|xmol/L,Z=-0.72,P= 0.47].The effective treatment resulted in the recover of cough threshold C5 to normal level in 6 of 12 patients with increased cough sensitivity to capsaicin.Conclusion Cough sensitivity in upper airway cough syndrome is heterogeneous and overlapped with normal value.Therefore,upper airway cough syndrome is not always consistent with the concept of cough hypersensitivity syndrome.