ABSTRACT
<p><b>BACKGROUND</b>The current diagnostic algorithms for chronic cough require the establishment of the primary presumptive causes followed by the confirmation of diagnosis with the specific therapies. The aim of the study was to investigate the discrepancy between presumptive and definite causes and its clinical implication.</p><p><b>METHODS</b>A total of 109 patients with chronic cough underwent laboratory investigations to identify the cause of cough; including sinus computerized tomography (if needed), histamine bronchial provocation, induced sputum cytology and 24-hour esophageal pH or multi-channel intraluminal impedance combined with pH monitoring. The presumptive causes were confirmed by treating them sequentially. The difference between presumptive and definite causes of chronic cough was compared.</p><p><b>RESULTS</b>Single cause was more frequent in the definite diagnosis than in the presumptive diagnosis (78.9% vs. 54.1%, χ(2) = 15.01, P = 0.0001). In contrast, multiple causes were significantly fewer in definite diagnosis than in the presumptive diagnosis (15.6% vs. 37.6%, χ(2) = 13.53, P = 0.0002). There was a discrepancy between definite and presumptive causes in 30 patients (27.5%). Compared with the presumptive causes, definite upper airway cough syndrome (24.8% vs. 11.9%, χ(2) = 6.0, P = 0.01) and gastroesophageal reflux disease (6.4% vs. 0, χ(2) = 7.23, P = 0.007) was more frequent as a single cause of chronic cough while cough variant asthma plus gastroesophageal reflux disease (3.7% vs. 11.9%, χ(2) = 5.17, P = 0.02) and upper airway cough syndrome plus nonasthmatic eosinophilic bronchitis (0 vs. 9.2%, χ(2) = 10.48, P = 0.001) were fewer as multiple causes of chronic cough.</p><p><b>CONCLUSIONS</b>A discrepancy was common between presumptive and definite causes of chronic cough. To treat presumptive causes sequentially may be a suitable solution for avoidance of erroneous multiple causes and possible over-treatment.</p>
Subject(s)
Adult , Female , Humans , Male , Middle Aged , Chronic Disease , CoughABSTRACT
<p><b>BACKGROUND</b>There is currently considerable interest in the potential value of selective inhibitors of cyclic nucleotide phosphodiesterase 4 in the treatment of asthma. However, whether they influence eosinophilic airway inflammation-associated cough remains unclear. The objective of this study was to investigate the effects of selective phosphodiesterase 4 inhibitor SB207499 on cough response and airway inflammation in guinea pigs sensitized and challenged with ovalbumin.</p><p><b>METHODS</b>Forty sensitized guinea pigs were randomly divided into four groups: control (n = 10), challenge (n = 10), SB207499 (n = 10) and aminophylline (n = 10), then challenged with aerosol of 1% ovalbumin or saline. Two hours later, animals were intraperitoneally injected with either saline, 25 mg/kg of SB207499 or aminophylline. At the 24th hour, the injection was repeated with 2.5 mg/kg and 25 mg/kg SB207499 or aminophylline, then cough response to inhaled capsaicin and airway responsiveness to methacholine inducing a 150% of the peak airway pressure to the baseline (PC150) was measured. Finally, total cell number and differentials in bronchoalveolar lavage fluid were analysed.</p><p><b>RESULTS</b>The cough frequency per 3 minutes and PC150 in the challenge group were (22 +/- 4) times/3 minutes and (198 +/- 54) microg/ml, which were significantly different from (6 +/- 2) times/3 minutes and (691 +/- 81) microg/ml in the control group (P < 0.05, respectively). The injection of 25 mg/kg SB207499 significantly inhibited the increased cough response and airway hyperresponsiveness, the cough frequency and PC150 in guinea pigs were (13 +/- 2) times/3 minutes and (680 +/- 81) microg/ml (P < 0.05), which differed significantly from (18 +/- 2) times/3 minutes and (400 +/- 86) microg/ml after the administration of the same dose of aminophylline (P < 0.05). The inhibition of SB207499 on cough response was dose-dependent. Similarly, SB207499 decreased the total cell number and percentage of eosinophils in bronchoalveolar lavage fluid to (2.1 +/- 0.5) x 10(6)/ml and (20 +/- 5)% respectively, which were significantly different from (3.2 +/- 0.5) x 10(6)/ml and (29 +/- 5)% in the aminophylline group (P < 0.05, respectively) or (4.2 +/- 0.7) x 10(6)/ml and (35 +/- 4)% in the challenge group (P < 0.05, respectively).</p><p><b>CONCLUSION</b>Phosphodiesterase 4 inhibitor may be more useful than aminophylline for cough associated with eosinophilic airway inflammation via inhibiting airway inflammation and airway hyperresponsiveness.</p>