No abstract

Background: It has been proposed that the pH of airway lining fluid may regulate the fractional exhaled concentration of nitric oxide (FE NO ) in respiratory disease. Methods: FE NO , exhaled breath condensate (EBC) pH, and EBC concentrations of nitrite plus nitrate (NO 2 / NO 3 ) were compared in 12 subjects with stable asthma, 18 with stable cystic fibrosis (CF), and 15 healthy control subjects. Eight of the CF patients were studied on a separate occasion at the start of a pulmonary exacerbation. Results: FE NO was significantly greater in asthmatic subjects than in control subjects (mean 35 v 9 ppb, p,0.001). EBC pH, however, was similar in the asthmatic and control groups (median 5.82 v 6.08, p = 0.23). Levels of NO 2 /NO 3 were on average higher in EBC samples from asthmatic subjects, but the difference was not significant. In patients with stable CF both the FE NO (mean 4 ppb, p,0.001) and EBC pH (median 5.77, p = 0.003) were lower than in the control group. Levels of EBC NO 2 /NO 3 (median 29.9 mM; p = 0.002) in patients with stable CF, in contrast, were significantly higher than in control subjects. During CF exacerbations, EBC pH was further reduced (median 5.30, p = 0.017) but FE NO and NO 2 /NO 3 were unchanged.Conclusions: These findings demonstrate a dissociation between EBC pH and FE NO in inflammatory airways disease.

Background: Chronic cough is a common symptom which causes significant levels of morbidity. It is becoming increasingly well characterised by research taking place in specialist cough clinics, where successful treatment rates are high. However, there is a paucity of data regarding the symptom complex of chronic cough in the community. This report details the results of a postal questionnaire survey sent to individuals requesting further information on chronic cough.

Chronic cough is a common and distressing symptom. A novel algorithm has been developed for the management of chronic cough, in which an assessment of clinical probability of disease determines the need to proceed to investigation.In this study, the performance of this algorithm in clinical practice was prospectively evaluated. A total of 131 consecutively referred patients (86 females) whose principal presenting symptom was a cough of duration .8 weeks were studied. Their age (median (range)) was 60 (16-88) yrs and cough duration 5.9 (0.2-65) yrs.A cause of cough was established in 93% of cases. The most frequent diagnoses were asthma (24% of cases), gastro-oesophageal disease (22%), post-viral cough (8%), bronchiectasis (8%) and interstitial lung disease (8%). Primary pulmonary disease was significantly more likely in patients with a productive cough and in patients with an abnormal chest radiograph. Only a small proportion (,8%) of patients had multiple causes of cough. The probability of treatment started on the basis of a high clinical suspicion of either asthma, gastro-oesophageal disease or rhinitis being successful was 74%. Overall, 26% of the patients were managed successfully without the need for any form of investigation other than chest radiography and spirometry.Use of the algorithm resulted in identification of the cause of cough and successful treatment in the large majority of cases. It is concluded that this protocol has the potential to improve management by providing a structured approach, reducing the number of investigations performed, and minimising unnecessary delays in treatment.

Among patients attending specialist cough clinics there is an excess of females, but the reason for this sex difference is unknown. We tested the hypothesis that the sensitivity of the cough reflex is greater in female compared with male patients with chronic cough. Inhalation cough challenges with capsaicin and citric acid were performed in a large group of patients with chronic cough. The concentrations of tussive agent causing two (C2) and five (C5) coughs were calculated. Measurements of capsaicin cough reflex sensitivity (median [interquartile range]) were significantly lower for female patients compared with male patients (C2: 1.9 [0.5 to 5.5] versus 5.3 [2.2 to 11.5] micro M, p = 0.0026; C5: 8.6 [2.2 to 34.0] versus 51.2 [7.2 to > 100] micro M, p = 0.0007). Similarly for citric acid challenge, values were significantly lower for female compared with male patients (C2: 53.5 [17.3 to 145.4] versus 118.1 [41.4 to 381.7] mM, p = 0.0064; C5: 300.0 [97.1 to > 1,000] versus 830.4 [300.0 to > 1,000] mM, p = 0.032). There were significant correlations between capsaicin and citric acid C2 values (r(s) = 0.54, p < 0.0001) and C5 values (r(s) = 0.57, p < 0.0001). These findings indicate a sex difference in cough sensitivity in patients with chronic cough, as previously reported in healthy volunteers. This may explain the female preponderance in cough clinics.

BackgroundOver 30% of adult patients with pleural infection either die and/or require surgery. There is no robust means of predicting at baseline presentation which patients will suffer a poor clinical outcome. A validated risk prediction score would allow early identification of high-risk patients, potentially directing more aggressive treatment thereafter.ObjectivesTo prospectively assess a previously described risk score (RAPID - Renal (urea), Age, fluid Purulence, Infection source, Dietary (albumin)) in adults with pleural infection.MethodsProspective observational cohort study recruiting patients undergoing treatment for pleural infection. RAPID score and risk category were calculated at baseline presentation. The primary outcome was mortality at 3 months; secondary outcomes were mortality at 12 months, length of hospital stay, need for thoracic surgery, failure of medical treatment, and lung function at 3 months.ResultsMortality data were available in 542 of 546 (99.3%) patients recruited. Overall mortality was 10% (54/542) at 3 months and 19% (102/542) at 12 months. The RAPID risk category predicted mortality at 3 months; low-risk (RAPID score 0–2) mortality 5/222 (2.3%, 95%CI 0.9 to 5.7), medium-risk (RAPID score 3–4) mortality 21/228 (9.2%, 95%CI 6.0 to 13.7), and high-risk (RAPID score 5–7) mortality 27/92 (29.3%, 95%CI 21.0 to 39.2). C-statistics for the score at 3 and 12 months were 0.78 (95%CI 0.71 to 0.83) and 0.77 (95%CI 0.72 to 0.82) respectively.ConclusionsThe RAPID score stratifies adults with pleural infection according to increasing risk of mortality and should inform future research directed at improving outcomes in this patient population.

No abstract

TRPV1 is a modulator of noxious stimuli known to be important in the cough reflex. We have compared the expression of TRPV1 in normal human airways and those from patients with chronic cough and found that there is up regulation in airways smooth muscle in disease. This increased expression appears to be intracellular and we have therefore examined the role of intracellular rat and human TRPV1 activity was found using intracellular calcium signalling with human intracellular TRPV1 being located in a thapsigargin insensitive compartment. Increase in TRPV1 activity may have a role in the airway hypersensitivity seen in chronic cough.