Ewa-Lena Johansson

Dyspnea from Exercise in Cold Air is Not Always Asthma

In the absence of other explanations, exercise-induced dyspnea is often labeled as a manifestation of asthma. The aim of this study was to use exercise provocation in cold air among patients with exercise-induced dyspnea, but without any bronchoconstriction, in order to study induced symptoms and different physiological parameters and to measure the possible influence of exercise in cold air on capsaicin cough sensitivity. Eleven patients with exercise-induced dyspnea but no asthma, along with 11 healthy controls, performed a capsaicin inhalation provocation on two occasions. One of these provocations was preceded by an exercise provocation in a cold chamber. Number of coughs, airway symptoms, spirometry, respiratory rate, pulse rate, end-tidal CO2, and PSaO2 were registered. During exercise, the patients coughed more than the controls and also had more airway symptoms. After exercise provocation, spirometry values remained unchanged, but capsaicin cough sensitivity was increased and end-tidal CO2 decreased among the patients, both in comparison to the controls and in comparison to the patients themselves prior to exercise. Exercise-induced dyspnea may be associated with hypocapnia from hyperventilation and increased capsaicin cough sensitivity. The diagnosis of exercise-induced asthma should be questioned when the patient has no signs of bronchoconstriction.

Capsaicin cough threshold test in diagnostics.

BACKGROUND Among patients with chronic unexplained cough, there is a recognized subgroup with respiratory symptoms induced by environmental irritants like chemicals and odours. The diagnosis of sensory hyperreactivity (SHR) has been suggested for this group of patients and can be made using a tidal breathing capsaicin inhalation test. The aim of the present study was to evaluate the ability of a single-breath, dose-response capsaicin threshold test to discriminate such patients from control subjects. METHODS A total of 46 patients with chronic cough and SHR who had previously shown a positive reaction in accordance with limits set for a tidal breathing capsaicin test were tested once with a single-breath, dose-response capsaicin cough threshold test, assessing capsaicin concentrations to evoke 2 (C2), 5 (C5) or 10 (C10) coughs. Twenty-nine subjectively healthy control subjects were also included and tested with the threshold method. RESULTS Patients had significantly lower C2, C5 and C10 in comparison to controls. From the results among patients and controls, sensitivity and specificity were calculated, and a receiver operating characteristic curve was constructed, showing excellent ability for C5 and C10 to discriminate patients from control subjects. CONCLUSIONS For patients with SHR and chronic cough, capsaicin cough sensitivity was once again confirmed to be increased, in this case, using the single-breath dose-response method. Limits set for cough reactions regarded as more sensitive than normal can be useful in diagnostics and further research. C5 seems to be the best measure to use in research and differential diagnostics.

Small and large airway reactions to osmotic stimuli in asthma and chronic idiopathic cough

BACKGROUND Chronic cough is a common symptom and related to several pulmonary, airway and heart diseases. When all likely medical explanations for the coughing are excluded, there remains a large group of patients with chronic coughing, which is mostly a cough reflex easily triggered by environmental irritants and noxious stimuli. The main aim of this study was to improve the diagnostic ability to differentiate chronic idiopathic cough (CIC) from asthma. METHODS Twenty-three patients with CIC, 16 patients with mild asthma and 21 control participants were included. The study consisted of three randomised bronchial provocations with osmotic stimuli: mannitol, eucapnic dry air and hypertonic saline. At each provocation lung function was assessed by spirometry and impulse oscillometry (IOS). RESULTS In a comparison of the groups, while the FEV1 measurements did not differ, the CIC group had increased airway resistance and reactance after provocation with hypertonic saline compared to the control subjects. After mannitol provocation the patients with asthma had significantly increased airway resistance compared to the controls and from eucapnic dry air provocations these patients had a significant reduction in spirometry values and increased airway resistance compared to both the patients with CIC and the controls. CONCLUSION The asthma group reacted in a predictable way with impaired lung function from osmotic provocations, whereas the patients with CIC demonstrated peripheral airway changes from hypertonic saline, also known to be a noxious stimulus. The IOS method uncovers differences between patients with CIC and control participants that contribute to our ability to provide a correct diagnosis.

Reply to correspondence regarding the paper "Ternesten-Hasséus E, Johansson EL, Millqvist E. Cough reduction using capsaicin. Respir Med. 2015 Jan;109(1):27-37.".

We are thankful for the interesting points of view and the discussion regarding our article, recently published in Respiratory Medicine [1]. The authors point out a possible mechanism behind our results, which demonstrated that pure capsaicin, taken orally, improved both cough symptoms and capsaicin cough sensitivity in patients with chronic cough. Several studies have shown a close connection between gastroesophageal reflux disease (GERD), reflux symptoms and chronic cough [2], though, somewhat contradictory to this finding, proton pump inhibitors have not turned out to be an effective way of treating chronic cough [3e5]. The Hull Reflux Cough Questionnaire, also used in our study, was originally developed to estimate GERD symptoms but was further shown to have high significance for the identification of chronic cough patients [6]. The mechanisms behind our findings could only be hypothesised, but Dr Faruqi and Dr Morice regard the most likely mechanism to be that regular exposure of the distal oesophagus to small amounts of capsaicin could lead to attenuation of capsaicin cough sensitivity in a manner analogous to that seen in the well-known topical therapy for pain. They also refer to earlier studies of poor bioavailability of ingested pure capsaicin [7], but recent research has shown developed methods for analysing capsaicin and dihydrocapsaicin in sera after oral ingestion of chilli [8]. It also seems likely that the commonly known effects from eating spicy food, like forehead sweating and runny nose, are the consequence of metabolised capsaicin entering the blood circulation, as is the probable effect behind the human ability to “get used to” having hot meals without such disturbing side effects. A depletion of neurotransmitters from the vanilloid receptor TRPV1 (also called the capsaicin receptor), following a regular exposure of capsaicin, could locally or systemically prevent cough by silencing receptors where cough is generated. It is easy to