Prospective validation of the RAPID clinical risk prediction score in adult patients with pleural infection: the PILOT study

BACKGROUND

Over 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.

OBJECTIVES

To prospectively assess a previously described risk score (the RAPID (Renal (urea), Age, fluid Purulence, Infection source, Dietary (albumin)) score) in adults with pleural infection.

METHODS

Prospective observational cohort study that recruited 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.

RESULTS

Mortality data were available in 542 out of 546 patients recruited (99.3%). Overall mortality was 10% at 3 months (54 out of 542) and 19% at 12 months (102 out of 542). The RAPID risk category predicted mortality at 3 months. Low-risk mortality (RAPID score 0-2): five out of 222 (2.3%, 95% CI 0.9 to 5.7%); medium-risk mortality (RAPID score 3-4): 21 out of 228 (9.2%, 95% CI 6.0 to 13.7%); and high-risk mortality (RAPID score 5-7): 27 out of 92 (29.3%, 95% CI 21.0 to 39.2%). C-statistics for the scores at 3 months and 12 months were 0.78 (95% CI 0.71-0.83) and 0.77 (95% CI 0.72-0.82), respectively.

CONCLUSIONS

The 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.

Advances in pulmonary and pleural malignant disorders

Lung and pleural malignancies remain common in the UK with poor survival rates due, at least in part, to late stage diagnosis. Diagnostic pathways aim to reduce the time taken for patients to reach a diagnosis and treatment, with the use of positron emission tomography and endobronchial ultrasound to provide staging information alongside diagnostics. Advances in molecular phenotyping of tumours and the development of treatments to target these have provided new therapeutic options which can be individualised to patients. In the UK, screening for lung cancer remains in its infancy, but provides a promising possibility for capturing curative disease. We provide an overview of the diagnostic process, therapeutic options and potential future screening programmes in pleural and pulmonary malignancies.

The respiratory system and the menopause

There is a decline in respiratory function with age that is independent of sex. However, women present with respiratory illness twice as commonly as men. This review will examine the effects of ovarian steroids on normal and abnormal respiratory function. The effects of age, menopausal status and hormone replacement therapy on specific symptoms such as dyspnoea, cough, airway hyper-responsiveness and snoring will be examined. Studies examining the effects of menopausal status and hormone replacement on the respiratory system are limited. While hormone replacement therapy may predispose to asthma, its use in women with the disease does not have an adverse effect.

Inhaled corticosteroids in chronic obstructive pulmonary disease: a pro-con perspective

Current guidelines limit regular use of inhaled corticosteroids (ICS) to a specific subgroup of patients with chronic obstructive pulmonary disease (COPD) in whom the forced expiratory volume in 1 s is <60% of predicted and who have frequent exacerbations. In these patients, there is evidence that ICS reduce the frequency of exacerbations and improve lung function and quality of life. However, a review of the literature suggests that the evidence available may be interpreted to favour or contradict these observations. It becomes apparent that COPD is a heterogeneous condition. Clinicians therefore need to be aware of the heterogeneity as well as having an understanding of how ICS may be used in the context of the specific subgroups of patients with COPD. This review argues for and against the use of ICS in COPD by providing an in-depth analysis of the currently available evidence.

Bilateral chylothorax: an unusual complication of cervical rib resection

Bilateral chylothorax is a rare cause of pleural effusions. Here we report an unusual acute presentation of bilateral chylothorax following thoracic outlet surgery. Unique to this case was the disparate characteristics of pleural fluid analyses with an exudate on the left and a transudate on the right. This report describes the recognition and management of bilateral chylothoraces, an uncommon but potentially serious complication of this frequently performed surgical procedure.

Pneumothorax: a tale of pain or spontaneity

Pneumothoraces may be due a variety of aetiologies. Here we present two different cases: one with a unilateral pneumothorax due an iatrogenic medical procedure and another of idiopathic spontaneous bilateral nature. Although both cases were initially managed conservatively, the latter case required surgical intervention. We also conduct a literature review of the aetiology and management of pneumothoraces.

Intermittent swelling in the chest; a case of spontaneous intermittent lung herniation

Herniation of the lung is uncommon and occurs due to protrusion of the lung beyond the confines of the thoracic cavity through an abnormal opening in the chest wall. Any condition associated with raised intrathoracic pressure or that which weakens the thoracic wall may result in lung herniation. We present a case of spontaneous lung herniation which was managed successfully by minimally invasive thoracic surgery.

UK national survey of thoracic ultrasound in respiratory registrars

Thoracic ultrasound training has become part of the respiratory medicine curriculum. Data on training, access to teaching and achievement of competency in thoracic ultrasound by respiratory specialty trainees are scarce. Using the web-based kwiksurveys, we surveyed current respiratory specialty trainees (STs) in the UK. 177 responses were recorded. Nearly three-quarters of trainees had access to bedside ultrasound but only 15.3% had regular ultrasound training. Overall, 28.8% had achieved level 1 competency but only 44.4% of trainees at ST6 and above were level 1 competent. The majority of respiratory trainees have access to thoracic ultrasound but structured training is limited, with only a small proportion of trainees attaining level 1. More structured training and mentoring is needed to enable trainees to achieve the required competencies.

Pleural abnormalities: thoracic ultrasound to the rescue!

Diaphragmatic hernias that are diagnosed in adulthood may be traumatic or congenital in nature. Therefore, respiratory specialists need to be aware of the presentation of patients with these conditions. In this report, we describe a case series of patients with congenital and traumatic diaphragmatic hernias and highlight a varied range of their presentations. Abnormalities were noted in the thorax on the chest radiographs, but it was unclear as to the nature of the anomaly. The findings on thoracic ultrasound conducted by a pulmonologist helped to direct appropriate investigations avoiding unnecessary interventions. Instead of pleural effusions, consolidation or collapse, thoracic computed tomography demonstrated diaphragmatic hernias which were managed either conservatively or by surgery. There is increasing evidence that pulmonary specialists should be trained in thoracic ultrasonography to identify pleural pathology as well as safely conducting pleural-based interventions.

Pins and needles and unilateral foot drop: a presentation of sarcoidosis

We describe a case of sarcoidosis in a 57-year-old man who presented with neurological symptoms of pins and needles in both of his hands, left leg weakness and left foot drop. Neurophysiological examination revealed asymmetric motor and sensory polyneuropathy. Common peroneal nerve involvement accounted for the left foot drop. Thoracic CT scan revealed bilateral hilar and mediastinal lymphadenopathy. He had hypercalcaemia and raised serum ACE level. Histological examination of a mediastinal lymph node showed non-caseating epithelioid cell granulomas consistent with the diagnosis of sarcoidosis. There was no evidence of acid-fast bacilli or fungi on special stains. This case highlights the importance of considering sarcoidosis as a potential diagnosis in patients presenting with peripheral neuropathy. Although response to corticosteroids and immunosuppressive therapy may be seen, in our case the patient's neurological deficit remained persistent despite treatment.

Comparison of the effect of high-dose inhaled budesonide and fluticasone on adrenal function in patients with severe chronic obstructive pulmonary disease

INTRODUCTION:

Chronic obstructive pulmonary disease (COPD) is a leading cause of respiratory-related morbidity and mortality. Inhaled steroids are frequently used in patients with moderate to severe disease and may lead to adrenal suppression.

OBJECTIVES:

The aim of this study was to compare the effect of inhaled budesonide/formoterol with inhaled fluticasone/salmeterol in severe COPD.

METHODS:

It was a prospective open-label crossover study of 22 patients. Adrenal suppression was measured by overnight urinary cortisol/creatinine ratio. The measurements were taken while patients were on either combination for at least 4 weeks.

RESULTS:

A total of 12 patients completed the study. The mean age was 64 years (8 males, 4 females). The mean FEV1 was 1 L (range, 0.5-1.8). There was no significant difference in adrenal suppression measured by overnight urinary cortisol/creatinine ratio (budesonide 5.2 ± 4.3, fluticasone 4.7 ± 3.1; 95% CI -2.2 to 1.2; P = 0.52) and urinary cortisol concentration (budesonide 51 ± 53, fluticasone 43 ± 31 [nmol/l]; 95% CI -35 to 20; P = 0.56).

CONCLUSION:

Inhaled budesonide and fluticasone have no significantly different effect on adrenal function in moderate to severe COPD. The adverse event profile of high-dose inhaled steroids should not influence the choice of medication.

National audit of supported discharge programmes for management of acute exacerbations of chronic obstructive pulmonary disease 2008

The 2008 U.K. national chronic obstructive pulmonary disease (COPD) audit examined the use of supported discharge programmes (SDPs) in clinical practice against British Thoracic Society guidelines. 98% of acute U.K. trusts participated. SDPs were available in 142 of 239 (59%) units. 1630 of 8971 (18%) patients with COPD were treated within SDPs. Median (IQR) stay in hospital for patients within SDPs and those not accepted for SDPs was 3 (1-6) days and 6 (3-11) days (p<0.001), and mortality within 90 days of admission was 4.3% and 6.7%, respectively. SDPs within the U.K. are safe and effective and reduce length of hospital stay without adverse effects on mortality.

Unusual asthma syndromes and their management

Asthma usually presents with symptoms of wheeze, dyspnoea and cough. However, clinicians should be aware of atypical presentation of this disorder when cough is the main or only symptom in conditions such as cough-variant asthma, nonasthmatic eosinophilic bronchitis and atopic cough. Early diagnosis and treatment of these conditions with inhaled corticosteroids improves symptoms in the majority of patients. Up to 10% of patients with asthma remain poorly controlled in spite of optimal standard therapy. These patients have been encompassed under the term 'treatment-refractory asthma' (TRA), have the greatest morbidity and are responsible for more than 50% of healthcare costs. In this review we discuss investigations, management and pathophysiology of the various phenotypes of atypical presentations of asthma as well as novel biological agents licensed and those that have been reported in clinical trials in terms of their efficacy and safety in TRA.

Spontaneous pneumomediastinum: a rare complication of bronchial asthma

Pneumomediastinum is a rare complication of an acute exacerbation of asthma. We describe a 28-year-old female who was admitted to hospital with acute severe exacerbation of asthma and developed a spontaneous pneumomediastinum (SPM) with associated subcutaneous emphysema. She was successfully managed conservatively. On follow up there was resolution of the subcutaneous emphysema and the pneumomediastinum, clinically and radiologically. SPM although usually a self-limiting condition, can occasionally be life threatening. Therefore, it is important to raise the awareness of this potential complication of asthma.

EXPRESSION AND CHARACTERIZATION OF THE INTRACELLULAR VANILLOID RECEPTOR (TRPV1) IN BRONCHI FROM PATIENTS WITH CHRONIC COUGH

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.

Diagnostic pitfall: Mycobacterium avium complex pulmonary infection and positive ANCA

We report the case of a 58-year-old female who presented with productive cough, weight loss, pulmonary nodular infiltrates and cavitations. She had a positive anti-neutrophil cytoplasmic antibodies (ANCA) test. A diagnosis of vasculitis was considered and a video-assisted thoracoscopic biopsy of the lung nodules was organised. However, prior to the biopsy, the sputum results revealed the presence of acid-fast bacilli, which were identified as Mycobacterium avium complex. A repeat ANCA assay was positive for atypical ANCA with negative proteinase-3 and myeloperoxidase titres. The patient was treated with rifampicin, ethambutol and clarithromycin with clinical and radiological improvement. The objective of this report is to highlight a rare association between positive ANCA titres and a non-tuberculous mycobacterial infection as a misdiagnosis and treatment of this patient with immunosuppressive therapy might have led to serious consequences.

Quality of life measurements and bronchodilator responsiveness in prescribing nebulizer therapy in COPD

Nebulized bronchodilators are widely regarded as the optimal treatment for maintenance therapy in patients with severe chronic obstructive pulmonary disease (COPD). The aim of the study was to assess whether detailed physiological, functional and quality of life-related measurements can assist in determining the requirement for nebulized bronchodilator therapy in patients with moderate to severe COPD. This was an unblinded, randomized, crossover study that compared intermediate (120mcg ipratropium bromide and 600mcg of salbutamol using metered dose inhaler (MDI) and spacer) and high dose (nebulized 500 mcg ipratropium bromide and 2.5 mg salbutamol) bronchodilator therapy, on physiological, functional and quality of life-related measurements in patients with COPD. A total of 25 patients (12 female), mean (SD) age 68 (7) years, FEV1 45 (10) % predicted completed the study. There was no statistically significant difference between the treatments in the pre- and post-bronchodilator lung function values, six-minute walk distance, breathlessness score or quality of life questionnaires. Fifteen patients preferred bronchodilator therapy with nebulizer and 10 with MDI and spacer. In 20 patients at least one positive response in quality of life score, lung function or six-minute walk, was observed on the preferred treatment.

Only a proportion of patients with moderate or severe COPD prefer nebulized bronchodilator therapy. This study found that none of the parameters singly or in combination were consistently predictive of patients' preference for nebulized bronchodilator therapy. Therefore, we suggest that clinicians institute a trial of stepping up to an intermediate dose of bronchodilators prior to introducing nebulized therapy. Chronic Respiratory Disease 2008; 5: 13—18

Concurrent pulmonary zygomycosis and Mycobacterium tuberculosis infection: a case report

A non-smoking 77-year old gentleman of Indian origin was admitted with a 4-month history of intermittent night sweats, haemoptysis and 6 kg of weight loss. CT scan of thorax demonstrated a 2.5 cm mass in the right middle lobe with multiple small nodules within the right lung and confirmed the presence of mediastinal and hilar lymph nodes.Fibreoptic bronchoscopy demonstrated a distorted right main bronchus, anterior shift of the right upper lobe and occlusion of the right middle lobe bronchus with a black necrotic ulcer. Mycobacterium tuberculosis was found in the bronchoalveolar lavage and histology demonstrated numerous fungal hyphae with a morphological appearance of zygomycetes within necrotic areas of tissue. Medical management with anti-fungal and anti-mycobacterial treatment was instigated as the patient's pre-existing IHD did not permit surgical intervention. Subsequently CT imaging following completion of therapy demonstrated improvement of the mass and a resolution of the associated nodules. The patient has been followed for 6 months to date and there has been no recurrence of symptoms. Recent bronchoalveolar lavage cultures have been negative for M. tuberculosis and zygomycetes.

Chronic persistent cough in the community: a questionnaire survey

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.

Methods

856 chronic cough questionnaires were sent out to members of the public who requested an information sheet following a national UK radio broadcast. Information regarding demography, history of cough, previous treatment and physical, psychological and social effects of the cough was elicited.

Results

373 completed questionnaires were returned. Mean age was 65.3 years (SD 12.0, range 9–88 years). 73% were female and 2% current smokers. Median duration of cough was 6.5 years. 66% had no other coexisting respiratory diagnosis, whilst 24% reported asthma. Of those who responded, 91% had consulted a general practitioner regarding the cough and of them, 85% had been prescribed some sort of treatment. 61% had seen at least one hospital specialist. Commonly reported associated physical symptoms included breathlessness (55%), wheeze (37%), fatigue (72%) and disturbed sleep (70%). Incontinence occurred in 55% of women. Similarly, the majority reported psychological effects such as anger or frustration (83%), anxiety (69%) and depression (55%). 64% felt that the cough interfered with their social life.

Conclusion

Chronic cough causes a high level of morbidity in the community, which results in a correspondingly high rate of healthcare utilisation. Demography and symptomatology seems to be similar to that reported from specialist centres, but successful treatment of the cough was uncommon, despite a high number of medical consultations in both primary and secondary care. If understanding of this debilitating but eminently treatable condition is enhanced, management of chronic cough will improve and many patients will be helped.

Ten years of viral and non-bacterial serology in adults with cystic fibrosis

Viral infections are associated with pulmonary exacerbations in children with cystic fibrosis (CF), but few studies have addressed the frequency in adults. This paper investigates the frequency and impact of viral infections in adults with CF receiving intravenous antibiotics. Pre- and post-treatment spirometry, inflammatory markers and antibody titres against influenza A, influenza B, adenovirus, respiratory syncytial virus, Mycoplasma pneumoniae, Chlamydia psittaci, and Coxiella burnetti were analysed over a 10-year period. Non-bacterial infections were identified in 5.1% of 3156 courses of treatment. The annual incidence of admissions per patient associated with viral infection was 4.9%. The presence of viral infection in association with a pulmonary exacerbation did not adversely affect lung function or inflammatory markers in the short term. Adults with CF have a lower incidence of respiratory viral infections associated with pulmonary exacerbations requiring intravenous antibiotics compared to children and infants with CF.

Poster discussion: summary

The Fourth International Cough Symposium took place in London between the 29th of June and 1st of July 2006. There were overall 22 posters presented during the meeting. These posters were divided into the following sections: methods of cough investigations, definitions of cough, receptor mechanisms, neural pathways, animal experiments and clinical aspects of cough. This review will focus on the discussions related to the posters.

Investigation and management of chronic cough using a probability-based algorithm

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.

Exhaled breath condensate pH and exhaled nitric oxide in allergic asthma and in cystic fibrosis

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 (NO2/NO3) 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 NO2/NO3 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 NO2/NO3 (median 29.9 microM; 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 NO2/NO3 were unchanged.

CONCLUSIONS

These findings demonstrate a dissociation between EBC pH and Fe(NO) in inflammatory airways disease.

Cough. 1: Chronic cough in adults

The investigation and treatment of chronic cough in adults is generally rewarding, provided there is an understanding of its aetiology, particularly when it arises from sites outside the respiratory tract.

Abnormal oesophageal motility in patients with chronic cough

BACKGROUND

Although gastro-oesophageal reflux is a recognised cause of chronic cough, the role of oesophageal dysmotility is unknown. The aim of this study was to determine the prevalence of abnormal oesophageal motility in a selected group of patients with chronic cough.

METHODS

Oesophageal manometry and 24 hour pH monitoring were performed in 43 patients with chronic cough, 34 of whom had symptoms suggestive of gastro-oesophageal reflux. Comparative manometric measurements were made in 21 healthy subjects.

RESULTS

Nine patients with chronic cough had normal manometry and 24 hour pH. Of the remaining 34 patients, 11 (32%) had abnormal manometry alone, five (15%) had abnormal 24 hour pH monitoring alone, and in 18 (53%) both tests were abnormal. Only one patient in the control group had manometric abnormalities.

CONCLUSIONS

These results point to a previously unrecognised high prevalence of abnormal oesophageal manometry in patients presenting with chronic cough. Oesophageal dysmotility may therefore be important in the pathogenesis of cough in these patients.

A widely available method for the assessment of aerosol delivery in cystic fibrosis

Whilst nebulisers are commonly used in the treatment of cystic fibrosis (CF), nebulised aerosol lung deposition in individual patients is not routinely assessed in clinical practice. The present study was designed to evaluate whether a comparative measurement of aerosol lung deposition from nebulisers using a widely available scintigraphic method could be employed to assist the selection of the best system for individual patients. Lung deposition of the radiolabelled aerosol from the Pari LC Plus (Pari Medical Ltd) nebuliser and the HaloLite Adaptive Aerosol Delivery (AAD) system (Profile Therapeutics Ltd) was measured using planar scintigraphy in 10 healthy volunteers and 6 CF patients. The HaloLite AAD delivered on average 2.1 times (P=0.003) as much aerosol to the lungs compared with Pari LC Plus. Only two subjects had higher lung deposition from Pari LC Plus than HaloLite AAD system. There was marked inter-individual variation in the deposition pattern in CF patients. The aerosol deposition from HaloLite AAD had higher central distribution than that obtained with the Pari LC Plus. The overall intersubject variability of the delivered dose was 56% with Pari LC Plus and 24% with HaloLite AAD (P<0.05). The measurement of aerosol deposition from nebulisers can be performed using a simple and widely available methodology, and may improve nebuliser selection in CF patients.

Measurement of gastric emptying in gastroesophageal reflux-related chronic cough

STUDY OBJECTIVES

Gastroesophageal reflux (GER) is one of the most common causes of chronic cough, but the mechanisms of GER-related cough are not well-understood. We tested the hypothesis that gastric emptying is delayed in patients with GER-related chronic cough.

DESIGN

We studied 12 patients (7 women; mean age, 53 years; age range, 37 to 68 years) with GER-related chronic cough and a control group of 27 asymptomatic healthy volunteers (16 women; mean age, 37 years; age range, 18 to 62 years). Gastric emptying scintigraphy was performed, and the time at which 50% of the radiolabeled material had left the stomach (T(1/2)) was calculated.

RESULTS

There was no statistically significant difference in T(1/2) values between healthy volunteers and subjects with GER-related cough (99 +/- 26 min vs 86 +/- 20 min, respectively; difference between the means, 13 min [95% confidence interval, -4 to 30 min]; p = 0.13).

CONCLUSIONS

Gastric emptying was not delayed in patients with GER-related chronic cough. The measurement of gastric emptying did not therefore provide further insights into the mechanisms of GER-related cough or clinically relevant information that would assist in patient management.

Sex-related differences in cough reflex sensitivity in patients with chronic cough

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.