Chronic tonsillar enlargement and cough: preliminary evidence of a novel and treatable cause of chronic cough

50% efficacy dose of intravenous lidocaine in supressing sufentanil-induced cough in children: a randomised controlled trial

BACKGROUND

Opioids such as sufentanil are used as anaesthetics due to their rapid action and superior analgesic effect. However, sufentanil induces a huge cough in paediatric patients. In contrast, intravenous (IV) lidocaine suppresses opioid-induced cough in children, but its use is limited due to anaesthetists' concern about its toxicity. Therefore, this study aimed to evaluate the effect of dose-dependent IV lidocaine on sufentanil-induced cough (SIC) in paediatric patients.

METHODS

A total of 188 patients aged 3-12 years scheduled for elective tonsillectomy with or without adenoidectomy were enrolled and divided into four groups depending on different dose of lidocaine: A (0 mg.kg-1), B (1 mg.kg-1), C (1.5 mg.kg-1), and D (2 mg.kg-1). The primary outcome was the SIC grade observed during the induction of general anaesthesia. The secondary outcomes were the incidence of SIC, mean arterial pressure, and heart rate at T0, T1, T2, T3, T4, and T5.

RESULTS

The SIC grade was significantly different between groups A and D (P = 0.04) and between groups B and D (P = 0.03). Moreover, the incidence of SIC in groups A, B, C, and D was 81%, 87%, 68%, and 64%, respectively, and the difference between groups B and C (P = 0.03) and between groups B and D (P = 0.0083) was statistically significant. No statistical differences were observed in the hemodynamic parameters between the groups. The incidence of severe cough was statistically different between group D and group A (P < 0.0001), between group D and group B (P < 0.0001), and between group D and group C (P < 0.0001) respectively.

CONCLUSIONS

Lidocaine suppresses SIC in a dose-dependent manner without severe adverse events. IV lidocaine can be used in paediatric patients safely and efficiently, and the median effective dose was 1.75 mg/kg.

TRIAL REGISTRATION

This study was approved by the Institutional Review Board of Yichang Central People's Hospital (HEC-KYJJ-2020-038-02), The trial was registered at www.chictr.org.cn (ChiCTR2100053006).

ERS International Congress 2023: highlights from the Airway Diseases Assembly

In this review, early career and senior members of Assembly 5 (Airway Diseases, Asthma, COPD and Chronic Cough) present key recent findings pertinent to airway diseases that were presented during the European Respiratory Society International Congress 2023 in Milan, Italy, with a particular focus on asthma, COPD, chronic cough and bronchiectasis. During the congress, an increased number of symposia, workshops and abstract presentations were organised. In total, 739 abstracts were submitted for Assembly 5 and the majority of these were presented by early career members. These data highlight the increased interest in this group of respiratory diseases.

Guidelines for the management of chronic cough in adults. Endorsed by the French speaking society of respiratory diseases (Société de Pneumologie de Langue Française, SPLF), the Société Française d'Oto-Rhino-Laryngologie et de Chirurgie de la Face et du Cou (SFORL), the Société Française de Phoniatrie et de Laryngologie (SFPL), the Société Nationale Française de Gastro-entérologie (SNFGE)

Patients with chronic cough experience a high alteration of quality of life. Moreover, chronic cough is a complex entity with numerous etiologies and treatments. In order to help clinicians involved in the management of patients with chronic cough, guidelines on chronic cough have been established by a group of French experts. These guidelines address the definitions of chronic cough and the initial management of patients with chronic cough. We present herein second-line tests that might be considered in patients with cough persistence despite initial management. Experts also propose a definition of unexplained or refractory chronic cough (URCC) in order to better identify patients whose cough persists despite optimal management. Finally, these guidelines address the pharmacological and non-pharmacological interventions useful in URCC. Thus, amitryptilline, pregabalin, gabapentin or morphine combined with speech and/or physical therapy are a mainstay of treatment strategies in URCC. Other treatment options, such as P2 × 3 antagonists, are being developed.

[Guidelines for the management of chronic cough in adults]

Patients with chronic cough experience major alteration in their quality of life. Given its numerous etiologies and treatments, this disease is a complex entity. To help clinicians involved in patient management of patients, guidelines have been issued by a group of French experts. They address definitions of chronic cough and initial management of patients with this pathology. We present herein the second-line tests that might be considered in patients whose coughing has persisted, notwithstanding initial management. The experts have also put forward a definition of unexplained or refractory chronic cough (URCC), the objective being to more precisely identify those patients whose cough persists despite optimal management. Lastly, these guidelines indicate the pharmacological and non-pharmacological interventions of use in URCC. Amitriptyline, pregabalin, gabapentin or morphine combined with speech and/or physical therapy are mainstays in treatment strategies. Other treatment options, such as P2X3 antagonists, are being developed and have generated high hopes among physicians and patients alike.

WAO-ARIA consensus on chronic cough - Part III: Management strategies in primary and cough-specialty care. Updates in COVID-19

Background

Chronic cough management necessitates a clear integrated care pathway approach. Primary care physicians initially encounter the majority of chronic cough patients, yet their role in proper management can prove challenging due to limited access to advanced diagnostic testing. A multidisciplinary approach involving otolaryngologists and chest physicians, allergists, and gastroenterologists, among others, is central to the optimal diagnosis and treatment of conditions which underly or worsen cough. These include infectious and inflammatory, upper and lower airway pathologies, or gastro-esophageal reflux. Despite the wide armamentarium of ancillary testing conducted in cough multidisciplinary care, such management can improve cough but seldom resolves it completely. This can be due partly to the limited data on the role of tests (eg, spirometry, exhaled nitric oxide), as well as classical pharmacotherapy conducted in multidisciplinary specialties for chronic cough. Other important factors include presence of multiple concomitant cough trigger mechanisms and the central neuronal complexity of chronic cough. Subsequent management conducted by cough specialists aims at control of cough refractory to prior interventions and includes cough-specific behavioral counseling and pharmacotherapy with neuromodulators, among others. Preliminary data on the role of neuromodulators in a proof-of-concept manner are encouraging but lack strong evidence on efficacy and safety.

Objectives

The World Allergy Organization (WAO)/Allergic Rhinitis and its Impact on Asthma (ARIA) Joint Committee on Chronic Cough reviewed the recent literature on management of chronic cough in primary, multidisciplinary, and cough-specialty care. Knowledge gaps in diagnostic testing, classical and neuromodulator pharmacotherapy, in addition to behavioral therapy of chronic cough were also analyzed.

Outcomes

This third part of the WAO/ARIA consensus on chronic cough suggests a management algorithm of chronic cough in an integrated care pathway approach. Insights into the inherent limitations of multidisciplinary cough diagnostic testing, efficacy and safety of currently available antitussive pharmacotherapy, or the recently recognized behavioral therapy, can significantly improve the standards of care in patients with chronic cough.

Efficacy and safety of gefapixant, a P2X3 receptor antagonist, in refractory chronic cough and unexplained chronic cough (COUGH-1 and COUGH-2): results from two double-blind, randomised, parallel-group, placebo-controlled, phase 3 trials

BACKGROUND

Gefapixant is an oral P2X₃ receptor antagonist that has previously shown efficacy and safety in refractory chronic cough and unexplained chronic cough. We therefore aim to confirm the efficacy and safety of gefapixant in participants with refractory chronic cough and unexplained chronic cough.

METHODS

COUGH-1 and COUGH-2 were both double-blind, randomised, parallel-group, placebo-controlled, phase 3 trials. COUGH-1 was done in 156 sites in 17 countries and COUGH-2 in 175 sites in 20 countries. We enrolled participants who were 18 years or older with a diagnosis of refractory chronic cough or unexplained chronic cough of 1 year duration or more. Participants were also required to have a cough severity visual analogue scale score of 40 mm or more at screening and baseline. Eligible participants were randomly allocated (1:1:1), using a computer-generated allocation schedule, to one of three treatment groups: placebo, gefapixant 15 mg twice per day, or gefapixant 45 mg twice per day. All study treatments were given orally. Participants were treated over a 12-week main study period in COUGH-1 and a 24-week main study period in COUGH-2; followed by extension periods for a total of up to 52 weeks of treatment in both trials. The primary outcome was placebo-adjusted mean change in 24-h cough frequency at 12 weeks in COUGH-1 and 24 weeks in COUGH-2. Both studies were registered with ClinicalTrials.gov, NCT03449134 (COUGH-1) and NCT03449147 (COUGH-2).

FINDINGS

From March 14, 2018, (first participant screened) to July 26, 2019, (last participant screened) 732 patients were recruited in COUGH-1 and 1317 in COUGH-2. COUGH-1 randomly assigned and treated 730 participants (243 [33×3%] with placebo, 244 [33×4%] with gefapixant 15 mg twice per day, and 243 [33×3%] with gefapixant 45 mg twice per day); COUGH-2 randomly assigned and treated 1314 participants (435 [33×1%] with placebo, 440 [33×5%] with gefapixant 15 mg twice per day, and 439 [33×4%] with gefapixant 45 mg twice per day). Participants were mostly female (542 [74×2%] of 730 in COUGH-1 and 984 [74×9%] of 1314 in COUGH-2). The mean age was 59×0 years (SD 12×6) in COUGH-1 and 58×1 years (12×1) in COUGH-2, and the mean cough duration was 11·6 years (SD 9·5) in COUGH-1 and 11·2 years (9·8) in COUGH-2. Gefapixant 45 mg twice per day showed significant reductions in 24-h cough frequency compared with placebo at week 12 in COUGH-1 (18·5% [95% CI 32·9-0·9]; p=0·041) and at week 24 in COUGH-2 (14·6% [26·1-1·4]; p=0·031). Gefapixant 15 mg twice per day did not show a significant reduction in cough frequency versus placebo in both studies. The most common adverse events were related to taste disturbance: ageusia (36 [4·9%] of 730 in COUGH-1 and 86 [6·5%] of 1314 in COUGH-2), dysgeusia (118 [16·2%] in COUGH-1 and 277 [21·1%] in COUGH-2), hypergeusia (3 [0·4%] in COUGH-1 and 6 [0×5%] in COUGH-2), hypogeusia (19 [2·6%] in COUGH-1 and 80 [6·1%] in COUGH-2), and taste disorder (28 [3·8%] in COUGH-1 and 46 [3·5%] in COUGH-2).

INTERPRETATION

Gefapixant 45 mg twice per day is the first treatment to show efficacy with an acceptable safety profile in phase 3 clinical trials for refractory chronic cough or unexplained chronic cough.

FUNDING

Merck Sharp & Dohme.

Cough in Idiopathic Pulmonary Fibrosis

Chronic cough is experienced by most patients with idiopathic pulmonary fibrosis (IPF). It is often the first symptom and is associated with reduced quality of life, increased rates of depression and anxiety, more severe physiological impairment, and disease progression. Although not fully understood, recent gains in understanding the pathophysiology of chronic cough in IPF have been made. The pathophysiology is likely multifactorial and includes alterations in mucous production and clearance, architectural distortion, and increased cough reflex sensitivity, suggesting a role for targeted therapies and multidisciplinary treatment. Modifiable comorbidities can also induce cough in patients with IPF. There is a renewed emphasis on measuring cough in IPF, with clinical trials of novel and repurposed therapies for chronic cough emerging in this population. This review provides an update on the clinical characteristics, pathophysiology, and measurement of chronic cough in patients with IPF and summarizes recent developments in non-pharmacological and pharmacological therapies.

Upper Airway Cough Syndrome in Pathogenesis of Chronic Cough

Cough is one of the most important defensive reflexes. However, extensive non- productive cough is a harmful mechanism leading to the damage of human airways. Cough is initiated by activation of vagal afferents in the airways. The site of their convergence is particularly the nucleus of the solitary tract (nTS). The second-order neurons terminate in the pons, medulla and spinal cord and there is also the cortical and subcortical control of coughing.Upper airway cough syndrome (UACS) - previously postnasal drip syndrome - is one of the most common causes of chronic cough together with asthma and gastroesophageal reflux. The main mechanisms leading to cough in patients with nasal and sinus diseases are postnasal drip, direct irritation of nasal mucosa, inflammation in the lower airways, upper airway inflammation and the cough reflex sensitization. The cough demonstrated by UACS patients is probably due to hypersensitivity of the upper airways sensory nerve or lower airways sensory nerve, or a combination of both. Further studies are needed to clarify this mechanism.

Chronic cough in adults

Cough, a defense mechanism for clearing the airways of secretions, exudate, or foreign bodies, may become a troublesome symptom. Chronic cough, one of the most frequent symptoms requiring medical attention, is often not due to identifiable causes in adults. Chronic productive cough defines chronic bronchitis, and thus is present in 100% of these patients, and frequently in patients with bronchiectasis, cystic fibrosis, and chronic infectious respiratory diseases. However, chronic cough is most frequently dry. Thus, chronic cough in adults is a difficult syndrome requiring multidisciplinary approaches, particularly to diagnose and treat the most frequent identifiable causes, but also to decide which patients may benefit by treating the central cough hypersensitivity by neuromodulatory therapy and/or non-pharmacologic treatment (speech pathology therapy). Recent guidelines provide algorithms for diagnosis and assessment of cough severity; particularly chronic cough in adults. After excluding life-threatening diseases, chronic cough due to identifiable causes (triggers and/or diseases), particularly smoking and/or the most frequent diseases (asthma, chronic bronchitis, chronic obstructive pulmonary disease, eosinophilic bronchitis, and adverse reactions to drugs [angiotensin-converting enzyme inhibitors and sitagliptin]) should be treated by avoiding triggers and/or according to guidelines for each underlying disease. In patients with troublesome chronic cough due to unknown causes or persisting even after adequate avoidance of triggers, and/or treatment of the underlying disease(s), a symptomatic approach with neuromodulators and/or speech pathology therapy should be considered. Additional novel promising neuromodulatory agents in clinical development (e.g., P2X3 inhibitors) will hopefully become available in the near future.

Diagnosis and management of chronic cough: similarities and differences between children and adults

Cough is a natural process that protects the airway. Cough can occur spontaneously or voluntarily. It is considered chronic when it is present for longer than 4 weeks in children or 8 weeks in adults. In both, chronic cough causes patient distress and increased healthcare utilization. Etiologies of pediatric chronic cough include asthma, protracted bacterial bronchitis, tracheomalacia, habit cough, and various systemic disorders. While some diagnoses are identifiable by careful history alone, others require testing guided by specific pointers. Flexible fiberoptic bronchoscopy has been an important tool to identify etiologies of chronic cough that were not otherwise apparent. In adults, asthma and bronchitis are well-defined etiologies of chronic cough, but much chronic cough in adults is largely a conundrum.

Reviews of adult chronic cough report that at least 40% of adults with chronic cough have no medical explanation. Gastroesophageal reflux and upper airway cough syndrome (a.k.a. post-nasal drip) have been common diagnoses of chronic cough, but those diagnoses have no support from controlled clinical trials and have been subjected to multiple published critiques. Cough hypersensitivity is considered to be an explanation for chronic cough in adults who have no other confirmed diagnosis. Gabapentin, a neuromodulator, has been associated with a modest effect in adults, as has speech pathology. While habit cough has not generally been a diagnosis in adults, there is evidence for a behavioral component in adults with chronic cough. Treatment for a specific diagnosis provides a better outcome than trials of cough suppression in the absence of a specific diagnosis. More data are needed for chronic cough in adults to examine the hypothesized cough hypersensitivity and behavioral management. This article reviews etiologies and the treatment of chronic cough in children and the conundrum of diagnosing and treating chronic cough in adults.

Types and applications of cough-related questionnaires

Cough is a normal protective reflex that can effectively remove foreign bodies and secretions from the airway. However, excessive cough adversely affects a patient's physiological, psychological and social functions. Thus, it is important to effectively evaluate the severity of cough to determine its diagnosis and treatment. Cough severity can be assessed with subjective or objective tools. Herein, we summarize the subjective evaluation of cough severity with questionnaires.

Towards understanding and managing chronic cough

Chronic cough is a common and troublesome condition affecting approximately 12% of the general population. It is associated with poor quality of life with psychological, social and physical consequences. Patients typically complain of a dry irritating cough, driven by a strong urge to cough associated with a sensation or irritation located in the throat. Treatment of potential 'causes', ie asthma, gastro-oesophageal reflux disease and rhino-sinusitis, may produce a complete or partial response, but the response of some patients to opiates and alpha-2-delta ligand antagonists (gabapentin and pregabalin) supports the concept that this is primarily a neurological disorder, characterised by hyper-responsiveness of the nerves. Novel and highly effective neuronal treatments are in development and offer hope of better symptom control with fewer side effects within a few years. This review focuses on understanding the mechanism of chronic cough, current management approaches and research that may lead to novel therapies.

Chronic cough and a normal chest X-ray - a simple systematic approach to exclude common causes before referral to secondary care: a retrospective cohort study

Chronic cough is common in the community and can cause significant morbidity. It is not clear how closely treatment guidelines are used in general practice, or how often specialist referral is indicated. We aimed to assess the management of chronic cough in primary care before referral to a cough clinic, and to assess the outcome of managing chronic cough with an approach of simple investigation and empirical treatment trials. Data were extracted from the records of all patients attending a district general hospital respiratory clinic over a two-year period with isolated chronic cough lasting ⩾8 weeks. The clinic assessed symptoms with a cough-severity visual analogue scale and the Leicester Cough Questionnaire. Among 266 patients, the most frequent diagnoses were asthma (29%), gastro-oesophageal reflux (22%) and angiotensin-converting enzyme inhibitor use (14%). In all, 12% had unexplained chronic cough. Common diagnoses had often not been excluded in primary care: only 21% had undergone spirometry, 86% had undergone chest radiography and attempts to exclude asthma with corticosteroids had been made only in 39%. In the clinic few investigations were conducted that were not available in primary care. Substantial improvements in symptoms occurred with a median (interquartile range) total of 2 (2–3) clinic visits. We estimated that 87% of patients could have been managed solely in primary care; we did not identify distinguishing characteristics among this group. Most cases of chronic cough referred to secondary care could be managed with a simple and systematic approach, which is potentially transferrable to a community setting.

Advances in upper airway cough syndrome

Upper airway cough syndrome (UACS), previously referred to as postnasal drip syndrome, is one of the most common causes of chronic cough. However, the pathogenesis of UACS/postnasal drip syndrome remains unclear, and physicians in countries throughout the world have different definitions and ways of treating this disease. The various proposed pathogeneses of UACS include the early postnasal drip theory, subsequent chronic airway inflammation theory, and a recent sensory neural hypersensitivity theory. Additionally, some researchers suggest that UACS is a clinical phenotype of cough hypersensitivity syndrome. While the general principles involved in treating UACS are similar throughout the world, the specific details of treatment differ. This review summarizes the various definitions, pathogenic mechanisms, treatments, and other aspects of UACS, to aid clinicians in expanding their knowledge of how to diagnose and treat this syndrome.

Adult and paediatric cough guidelines: Ready for an overhaul?

Cough is one of the most common reasons that patients seek medical attention. Cough guidelines from numerous countries and societies are available to assist the clinician to investigate and manage patients with cough. We review some of the recent progress in the field of cough that may lead to revision of these guidelines. In adults with chronic cough, new causes such as obstructive sleep apnoea have been identified. A new terminology, cough hypersensitivity syndrome (CHS), has been proposed for patients with chronic cough, which emphasises cough reflex hypersensitivity as a key feature. New therapeutic options are now available, particularly for patients with refractory or idiopathic chronic cough, which include gabapentin, speech pathology management and morphine. There has been great progress in the assessment of cough with the development of validated quality of life questionnaires and cough frequency monitoring tools. In children, common aetiologies differ from adults and those managed according to guidelines have better outcomes compared to usual care. New diagnostic entities such as protracted bacterial bronchitis have been described. Paediatric-specific cough assessment tools such as the Parent/Child Quality of Life Questionnaire will help improve the assessment of patients. Further research is necessary to improve the evidence base for future clinical guideline recommendations. Guidelines in future should also aim to reach a wider audience that includes primary care physicians, non-specialists and patients.

An update on measurement and monitoring of cough: what are the important study endpoints?

Considerable progress has been achieved in the development of tools that assess cough. The visual analogue scale (VAS) for cough severity is widely used in clinical practice because it's simple and practical. The Leicester cough questionnaire (LCQ) and the cough-specific quality of life questionnaire (CQLQ) are the most widely used health status questionnaires for adults with chronic cough. They are well validated for assessing the impact of cough. Cough can be assessed objectively with challenge tests that measure the sensitivity of the cough reflex. Cough challenge tests are better used to determine the mechanism of action of therapy, rather than efficacy. Cough frequency monitoring, the preferred tool to objectively assess cough, is increasingly being used as primary end-points in clinical trials. The most widely used cough monitors are the Leicester cough monitor (LCM) and VitaloJak. They are ambulatory devices that consist of a microphone and recording device. Cough frequency monitors do not reflect the intensity or the impact of cough; hence their relationship with subjective measures of cough is weak. Cough should therefore be assessed with a combination of subjective and objective tools. There is a paucity of studies that have investigated the minimal important difference of cough frequency monitors, rendering further investigations needed.

The difficult-to-treat, therapy-resistant cough: why are current cough treatments not working and what can we do?

Cough can persist despite exhaustive diagnostic and therapeutic effort and has been termed 'idiopathic' or 'unexplained' but perhaps 'difficult to treat' cough is a more appropriate description. In this article the reasons for poor treatment response are discussed. These include a lack of physician fidelity to management guidelines, patient non-adherence and the lack of effective medicines. A number of randomized controlled trials have been undertaken including low dose opiate therapy, the use of a speech pathology intervention, oral antibiotics and antidepressants. The success or otherwise of such interventions will be discussed. A number of approaches to deal with the problem of 'difficult to treat cough' will be considered.

Novel antitussive strategies

Acute and chronic cough represent one of the most common symptoms of medical importance but effective pharmacotherapy is, to all intents and purposes, absent. Numerous initiatives targeting the recently discovered tussive pathways are in progress. Here, we review the current antitussive armamentarium and provide an update on the novel strategies and compounds in development.

Anatomy and neuro-pathophysiology of the cough reflex arc

Coughing is an important defensive reflex that occurs through the stimulation of a complex reflex arc. It accounts for a significant number of consultations both at the level of general practitioner and of respiratory specialists. In this review we first analyze the cough reflex under normal conditions; then we analyze the anatomy and the neuro-pathophysiology of the cough reflex arc. The aim of this review is to provide the anatomic and pathophysiologic elements of evaluation of the complex and multiple etiologies of cough.

New concepts in the management of chronic cough

There has been significant progress in the field of cough in the past 10 years. Obstructive sleep apnoea, tonsillar enlargement and environmental fungi have recently been described as causes of chronic cough. The advances in the assessment of gastro-oesophageal reflux (GOR) have led to a greater understanding of the relationship between cough and GOR and are likely to change the approach to managing patients with GOR-cough. The investigation of the phenotype of patients with idiopathic chronic cough has provided novel insights. Patients with an idiopathic chronic are predominantly female, have an onset of cough around the menopause and have a high prevalence of organ specific autoimmune disease, particularly hypothyroidism. The presence of bronchoalveolar lymphocytosis suggests there is homing of inflammatory cells from primary sites of autoimmune inflammation to the lungs. A heightened cough reflex is a key feature of most patients with chronic cough and has led some investigators to suggest that chronic cough be recognised as a unique entity called Cough Hypersensitivity Syndrome (CHS). A number of subjective and objective tools have been developed recently to assess cough severity. Antitussive drug development is an emerging and exciting area of cough research.

Controversies in the evaluation and management of chronic cough

Chronic cough that cannot be explained after basic evaluation is a common reason for patients to be referred to respiratory outpatient clinics. Asthma, gastroesophageal reflux, and upper airway disorders frequently coexist with chronic cough. There is some controversy as to whether these conditions are causes or aggravants of cough. Heightened cough reflex sensitivity is an important feature in most patients. There is good evidence that it is reversible when associated with upper respiratory tract infection, angiotensin-converting enzyme inhibitor medications, and chronic cough associated with eosinophilic airway inflammation. In many patients, heightened cough reflex sensitivity is persistent and their cough is unexplained. There are few therapeutic options for patients with unexplained chronic cough. There is a pressing need to understand the genetic, molecular, and physiological basis of unexplained chronic cough and to develop novel antitussive drugs that down-regulate cough reflex sensitivity.

Rhinosinusitis, laryngopharyngeal reflux and cough: an ENT viewpoint

Chronic cough is a common presentation. Postnasal drip (PND) and gastro-oesophageal reflux are mostly implicated in the aetiology. Directly examining the larynx can often help to demonstrate laryngitis or inter-arytenoid oedema that is mostly attributed to reflux. Although "the syndrome of postnasal drip" is considered as a major cause for chronic cough, evidence of its existence is mostly difficult to elicit on examination. Furthermore, the majority of patients with "postnasal drip" seen in ENT outpatients do not complain of cough. Evidence does suggest there is a link between postnasal drip and cough. The fact that some patients present with cough in association with this syndrome and others do not is still not well understood.

Postnasal drip and chronic cough: An open interventional study

BACKGROUND

The postnasal drip (PND) syndrome is often linked as a cause of chronic cough although this is disputed.

OBJECTIVES

We examined the effect of specific topical treatment of rhinosinusitis on cough in patients presenting with a chronic cough associated with a postnasal drip or 'nasal catarrh'.

METHODS

Patients presenting with a chronic cough and who complained of PND were enrolled and symptoms of PND and cough were assessed by questionnaire and by a capsaicin cough response. Rhinosinusitis was assessed by questionnaires, direct examination of the nose and by high-resolution computed tomography. In an open study, they were treated with fluticasone nasules, ipratropium bromide and azelastine nasal sprays for 28 days, after which they were re-assessed.

RESULTS

Eighteen out of 21 patients completed the study. All patients reported having the presence of mucus in the throat. Mean cough score improved post-treatment (p<0.05), but there was no significant change in capsaicin cough sensitivity or nasal catarrh questionnaire score. There was improvement in anterior nasal discharge symptom scores (p=0.005) and in endoscopic nasal scores post-treatment (p<0.01), with a tendency to improved PND scores.

CONCLUSION

In a pilot open 'real-life' study treatment targeted towards rhinosinusitis accompanying PND syndrome and chronic cough led to an improvement in cough. A randomised controlled study is now needed to confirm or refute these findings.

Measuring cough severity: Perspectives from the literature and from patients with chronic cough

Background

In order to assess severity of cough from patients' perspectives and capture the effects of treatment in clinical trials, a measurement tool must show evidence of validity and reliability. The purpose of this study was to characterize cough severity from patients' perspectives as the initial step in the development of a new patient-reported outcome (PRO) measure for use in clinical trials.

Methods

This focus groups study included patients with clinician confirmed chronic cough recruited from a large internal medicine clinic in the US. A semi-structured focus group guide was designed to elicit information about patients' experiences with cough severity and their characterization of symptoms. The focus group data were coded to identify concepts and terminology of cough severity.

Results

Three focus groups were conducted [n = 22; 6 male; mean age 66.1 (± 12.9)]. Etiology included GERD, asthma, bronchitis, post-nasal drip, and other. Three domains of cough severity were identified: frequency, intensity, and disruption. In addition to a single cough, participants in all focus groups described coughing in uncontrollable paroxysms they called "fits," "bouts," "spells," or "episodes." The urge to cough, described as an important sign of impending cough, was considered a component of cough frequency. Participants also described daytime activity and nighttime sleep disruption as an indication of cough severity. Finally, participants described variability in cough severity.

Conclusion

Results suggest that patients describe cough severity in terms of frequency, intensity, and disruptiveness, indicating these 3 domains should be addressed when evaluating cough severity and outcomes of treatment.

Developing antitussives: the ideal clinical trial

Antitussive drugs are amongst the most widely used medications worldwide; however no new class of drugs have been introduced into the market for many years. Trials showing patient benefit are scarce and have been hampered by the lack of objective and validated outcome measures. Recent improvements in the assessment of cough will facilitate better trials and aid the development of antitussive drugs. When conducting a trial, patient selection is of paramount importance. Patients with unexplained chronic cough and sub-acute cough following upper respiratory tract infection are ideal because they represent an unmet clinical need and an untapped market for pharmaceutical companies. Patients with asthma and chronic obstructive pulmonary disease are less suitable since cough suppression is not always desirable and the findings of trials may not be generalisable to all patients with cough. Randomized, placebo-controlled, double-blind clinical trials are obviously the gold standard. The choice of placebo, whether inert or active, depends on the incidence and severity of drug side-effects. The primary outcome measure should be objective and cough monitors are the ideal tool. Subjective outcome measures should be used to assess symptoms and health related quality of life. Properly conducted clinical trials are an opportunity to evaluate the benefits of currently available therapies and aid advances in the antitussive drug market.

Chronic cough and tonsillar hypertrophy: a case series

Two patients with intractable chronic cough were found to have tonsillar tissue impinging on their epiglottis. In both case, tonsillectomy was curative. The observations in these patients are consistent with a previous report indicating chronic cough from the uvula in contact with the epiglottis with cough cessation following uvulectomy.

Management of chronic cough

Cough that remains unexplained after basic clinical assessment is a common reason for referral to secondary care. Much of the evidence about management of isolated chronic cough is derived from case series; this evidence suggests that isolated chronic cough is usually due to asthma, gastro-oesophageal reflux disease, and upper airway conditions, and that it can be cured in most people by treatment of these conditions. However, there is increasing recognition that satisfactory control of chronic cough is not achieved in a substantial number of patients seen in secondary care. Moreover, there is a concern that perpetuation of the belief that chronic cough is solely due to the effects of comorbid conditions is inhibiting research into the pathophysiology of an abnormally heightened cough reflex, and jeopardising development of improved treatments. We advocate a change in emphasis, which makes a clear distinction between cough due to corticosteroid-responsive eosinophilic airway diseases and corticosteroid-resistant non-eosinophilic cough. We recommend that some factors with weak evidence of an association with cough are best viewed as potential aggravating factors of an intrinsic abnormality of the cough reflex, rather than the cause. We call for more research into the basic mechanisms and pharmacological control of an abnormally heightened cough reflex, and recommend ways to assess the effects of potentially antitussive treatments.

Prevalence, pathogenesis, and causes of chronic cough

Cough is a reflex action of the respiratory tract that is used to clear the upper airways. Chronic cough lasting for more than 8 weeks is common in the community. The causes include cigarette smoking, exposure to cigarette smoke, and exposure to environmental pollution, especially particulates. Diseases causing chronic cough include asthma, eosinophilic bronchitis, gastro-oesophageal reflux disease, postnasal drip syndrome or rhinosinusitis, chronic obstructive pulmonary disease, pulmonary fibrosis, and bronchiectasis. Doctors should always work towards a clear diagnosis, considering common and rare illnesses. In some patients, no cause is identified, leading to the diagnosis of idiopathic cough. Chronic cough is often associated with an increased response to tussive agents such as capsaicin. Plastic changes in intrinsic and synaptic excitability in the brainstem, spine, or airway nerves can enhance the cough reflex, and can persist in the absence of the initiating cough event. Structural and inflammatory airway mucosal changes in non-asthmatic chronic cough could represent the cause or the traumatic response to repetitive coughing. Effective control of cough requires not only controlling the disease causing the cough but also desensitisation of cough pathways.

Clinical assessment of chronic cough severity

The assessment of cough severity solely through consultation with the patient is limited by its subjective nature and variability of physician judgement. The assessment of cough has been hampered by a paucity of objective tools, those available have been poorly validated, non-standardized and are impractical for clinical use. Recent developments have overcome some of these problems and a variety of tools can now be used to assess cough that include visual analogue scales (VAS), quality-of-life questionnaires, cough reflex sensitivity measurement and automated cough frequency monitors. These tools can be used to validate the presence of cough and assess response to therapy. They will also have an important role in clinical trials.

Measurement of cough

Cough is one of the most common symptoms encountered by clinicians particularly when it is persistent. Assessment of cough is essential for determining treatment outcomes, testing new therapies and for study of pathophysiology and mechanisms. There are new tools for measuring different aspects of cough. Apart from the patient's subjective assessment of cough severity using clinical scores, the impact of cough on quality of life can be measured. Direct measurement of cough counts is now possible by using portable devices, but how the counts relate to severity is unclear. A measure of cough intensity is required. Cough reflex measured by response to inhaling citric acid or capsaicin provides a measure of cough sensitivity that may be related to cough severity. In many intervention studies of cough, the response has usually been measured in terms of physician assessment of cough and its changes in cough reflex. How the information obtained between these different measurements interrelate needs to be determined.

Uncommon causes of cough: ACCP evidence-based clinical practice guidelines

OBJECTIVES

To describe the uncommon causes of cough.

DESIGN/METHODOLOGY

An English language literature search by MEDLINE citations from 1975 through 2004 was used to identify publications on uncommon pulmonary and nonpulmonary disorders in which cough was present as the major or presenting symptom in >50% of those persons affected by the uncommon diseases.

RESULTS

A substantial number of uncommon or rare pulmonary and nonpulmonary disorders were identified. The uncommon occurrence of these diseases made it difficult to develop a meaningful evidence-based guideline to the diagnosis and therapy of many of the uncommon causes of cough. As cough was the major or presenting symptom, it was usually initially attributed to common respiratory diseases (eg, asthma or bronchitis). As a result, a substantial time lag existed from the onset of cough to the diagnosis of the etiologic entity. Diagnostic tests limited to the respiratory system did not always provide clues to the diagnosis of uncommon causes of cough.

CONCLUSIONS

Cough is the major or presenting symptom in many uncommon pulmonary and nonpulmonary disorders. A strong index of suspicion is essential to consider and diagnose the uncommon causes of cough. The diagnosis and management of cough in patients with uncommon causes of cough is dependent on the underlying etiology.

Cough frequency, cough sensitivity and health status in patients with chronic cough

BACKGROUND

Little is known about the frequency of cough in health and in patients with chronic cough.

METHODS

We measured cough frequency and its relationship with other markers of cough severity in 20 patients with chronic cough and 9 healthy subjects using the Leicester Cough Monitor (LCM), which is an automated ambulatory digital cough monitor that records sound only. All subjects had a 6-h recording and recordings were manually counted. A subgroup of 6 normals and 6 patients with a stable chronic cough had repeat measurements up to 6 months apart.

RESULTS

Mean (sem) cough counts/hour were 43(8) in patients with chronic cough and 2(1) in normals (mean difference 41; 95% confidence interval 24-59; P<0.001). The cough counts were repeatable (within subject standard deviation: 23 coughs/hour; intraclass correlation coefficient 0.8). Cough counts correlated significantly with physical (r=-0.6, P=0.03), social (r=-0.7, P=0.01) and total Leicester Cough Questionnaire (LCQ) health status scores (r=-0.6, P=0.03) and cough sensitivity (concentration of capsaicin causing 5 coughs: r=0.9, P=0.008).

CONCLUSION

We have shown that there are marked differences in cough frequency between patients with chronic cough and healthy subjects, that these measurements are repeatable, and that they correlate with cough-specific health status.