Capsaicin cough sensitivity in bronchiectasis.
BACKGROUND
Bronchiectasis is a suppurative airway disease characterised by persistent cough and sputum production associated with bronchial dilatation. A study was undertaken to determine whether cough sensitivity is increased in bronchiectatic patients.


METHODS
Twenty two patients with bronchiectasis and 20 healthy non-smoking controls matched for age and sex were recruited into the study. Quality of life (Leicester Cough Questionnaire score), total cough symptom score, and extent of bronchiectasis on HRCT scans were recorded. Cough sensitivity was assessed using incremental inhalation of capsaicin concentrations; the concentration at which 5 or more coughs occurred (C5) was recorded.


RESULTS
Patients with bronchiectasis had increased sensitivity to capsaicin compared with controls (mean (SE) log10 C5 1.22 (0.20) v 1.89 (0.21); p<0.03). Capsaicin sensitivity correlated positively with the Leicester Cough Questionnaire score (r = 0.64; p = 0.005) and inversely with the total cough symptom score (r = -0.58; p = 0.004), but not with the extent of the disease. It also correlated with forced expiratory volume in 1 second (FEV1) in litres (r = 0.58; p = 0.005) but not with FEV1 % predicted. Capsaicin sensitivity was not related to the presence of infected sputum or to corticosteroid or bronchodilator use.


CONCLUSIONS
: Patients with bronchiectasis have a sensitive cough reflex which reflects the severity of cough symptoms. A measure of cough severity could be part of health assessment for patients with bronchiectasis.
Torrego
A
A
National Heart and Lung Institute, Imperial College, Dovehouse Street, London SW3 6LY, UK.
Haque
R A
RA
Nguyen
L T
LT
Hew
M
M
Carr
D H
DH
Wilson
R
R
Chung
K F
KF
D001985:Bronchial Provocation Tests / Q000379:methods; D001987:Bronchiectasis / Q000503:physiopathology*; D016085:Bronchoconstrictor Agents; D002211:Capsaicin; D003371:Cough / Q000503:physiopathology; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012018:Reflex / Q000502:physiology
D016085:Bronchoconstrictor Agents; D002211:Capsaicin