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Introduction Up to 80% of patients with sarcoidosis report a chronic cough. The aim of this study was to investigate whether heightened cough reflex sensitivity (CRS) is an important mechanism and to establish if factors such as gender, serum ACE level and radiographic stage influence sensitivity thresholds. Methods Twenty-four patients with sarcoidosis (mean (SEM) age 49 (2) years, 63% female) were recruited from a specialist clinic and underwent assessment of CRS by a single-breath inhalation capsaicin cough challenge test to determine the concentration causing 5 or more coughs (C5). Anthropometric data, spirometry, serum ACE levels and radiographic stage were recorded. The effects of gender, age, ethnicity, radiographic stage and serum ACE levels on cough reflex sensitivity were investigated. CRS data of 134 healthy subjects from a previous study were used for comparison (Prudon B et al, Chest 2005;127:550). Results CRS was heightened in patients with sarcoidosis compared to healthy subjects (geometric mean (logSD) C5 13.5 (0.5) vs 158.5 (0.6) µmol/l, p<0.001). Female patients had a more sensitive cough reflex compared to males (geometric mean (logSD) C5 8.1 (0.5) vs 31.8 (0.5) µmol/l, p=0.007). Seven patients did not complain of cough; there was no difference in CRS compared to patients who reported cough (p=0.68). There was no difference in CRS between patients of Afro-Caribbean origin compared to non-Afro-Caribbean patients (geometric mean (logSD) C5 10.1 (0.5) vs 24.3 (0.6) µmol/l, p=0.09). Serum ACE levels correlated significantly with logC5 (r=0.74, p<0.001), with lower ACE levels being associated with a more sensitive cough reflex. There was no relationship between logC5 and age (r=-0.40, p=0.054) or radiographic stage (p=0.83). Conclusions Patients with sarcoidosis have a heightened CRS. This was increased to a greater degree in females, but age or radiographic stage had no effect. We report for the first time a link between serum ACE levels and cough reflex sensitivity, and hypothesise that low concentrations of serum ACE lead to increased airway tussigenic mediators such as bradykinin. Further studies should investigate whether cough receptors such as TRPV1 are upregulated in sarcoidosis. [ABSTRACT FROM AUTHOR]

Rationale: Hospitalised patients with acute exacerbation of COPD may deteriorate despite treatment, with early readmission being common., Objectives: To investigate whether neural respiratory drive, measured using second intercostal space parasternal muscle electromyography (EMGpara), would identify worsening dyspnoea and physician-defined inpatient clinical deterioration, and predict early readmission., Methods: Patients admitted to a single-site university hospital with exacerbation of COPD were enrolled. Spirometry, inspiratory capacity (IC), EMGpara, routine physiological parameters, modified early warning score (MEWS), modified Borg scale for dyspnoea and physician-defined episodes of deterioration were recorded daily until discharge. Readmissions at 14 and 28 days post discharge were recorded., Measurements and Main Results: 120 patients were recruited (age 70 ± 9 years, forced expiratory volume in 1 s (FEV1) of 30.5 ± 11.2%). Worsening dyspnoea, defined as at least one-point increase in Borg scale, was associated with increases in EMGpara%max and MEWS, whereas an increase in EMGpara%max alone was associated with physician-defined inpatient clinical deterioration. Admission-to-discharge change (Δ) in the normalised value of EMGpara (ΔEMGpara%max) was inversely correlated with ΔFEV1 (r = -0.38, p < 0.001) and ΔIC (r = -0.44, p < 0.001). ΔEMGpara%max predicted 14-day readmission (OR 1.13, 95% 1.03 to 1.23) in the whole cohort and 28-day readmission in patients under 85 years (OR 1.09, 95% CI 1.01 to 1.18). Age (OR 1.08, 95% CI 1.03 to 1.14) and 12-month admission frequency (OR 1.29, 1.01 to 1.66), also predicted 28-day readmission in the whole cohort., Conclusions: Measurement of neural respiratory drive by EMGpara represents a novel physiological biomarker that may be helpful in detecting inpatient clinical deterioration and identifying the risk of early readmission among patients with exacerbations of COPD., Trial Registration: NCT01361451., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/)