title: Utility of cough response during hypertonic histamine challenge in diagnosing asthma.
abstract: Airway responses to bronchial provocation tests are traditionally assessed with spirometry which necessitates considerable patient co-operation. It has been shown that coughing during bronchial provocation tests is related to the degree of bronchoconstriction which, in turn, is independent of patient co-operation. The aim of the present study was to evaluate the utility of coughing induced by the hypertonic histamine challenge in the differential diagnosis of asthma in a clinically relevant patient population. The study population consisted of 25 healthy volunteers, 30 asthmatics, and 82 non-asthmatic subjects with respiratory symptoms due to other diseases. Hypertonic histamine solution was administered with ultrasonic nebuliser with the challenges being videotaped. The cough response was expressed as the cumulative number of coughs divided by the final histamine concentration administered (CCR). The geometric mean (95% CI) of CCR for asthmatics was 302 (166-562) coughs per mg/ml, for the symptomatic controls 29.5 (20.0-43.7) coughs per mg/ml (p<0.001) and for the healthy controls 6.61 (3.02-14.5) (p<0.001) coughs per mg/ml. According to the ROC curve, the optimal cut-off point for logCCR was 2.22, with the specificity and sensitivity to detect asthma among symptomatic subjects being 86% and 70%. Cough response to hyperosmolar challenge may be useful in the differential diagnosis of airway diseases.
authors.affiliation: Department of Respiratory Medicine, Kuopio University Hospital, P.O. Box 1777, 70211 Kuopio, Finland. minna.purokivi@kuh.fi
authors.forename: Minna
authors.initials: M
authors.lastname: Purokivi
authors.forename: Heikki O
authors.initials: HO
authors.lastname: Koskela
authors.forename: Tiina
authors.initials: T
authors.lastname: Koistinen
authors.forename: Jarkko
authors.initials: J
authors.lastname: Magga
authors.forename: Keijo
authors.initials: K
authors.lastname: Peuhkurinen
authors.forename: Vesa
authors.initials: V
authors.lastname: Kiviniemi
authors.forename: Kirsi M
authors.initials: KM
authors.lastname: Kontra
mesh_terms: D000280:Administration, Inhalation; D000328:Adult; D019540:Area Under Curve; D001249:Asthma / Q000175:diagnosis*; D001985:Bronchial Provocation Tests / Q000379:methods; D003371:Cough / Q000139:chemically induced*; D003937:Diagnosis, Differential; D005240:Feasibility Studies; D005260:Female; D005541:Forced Expiratory Volume; D006632:Histamine; D017442:Histamine Agonists; D006801:Humans; D008297:Male; D008875:Middle Aged; D012462:Saline Solution, Hypertonic; D012680:Sensitivity and Specificity
chemical_list: D017442:Histamine Agonists; D012462:Saline Solution, Hypertonic; D006632:Histamine