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Chronic cough: how do cough reflex sensitivity and subjective assessments correlate with objective cough counts during ambulatory monitoring?

BACKGROUND: Cough reflex sensitivity, subjective estimates of cough frequency and cough-related quality of life have been used to assess cough and monitor treatment responses. The relationships between these measures and objective cough monitoring remain unclear and the usefulness of subjective assessments remains questionable. SUBJECTS: 62 patients with chronic cough (39 women) were studied. Mean age of patients was 54.9 (SD 12.2) years, with a median duration of cough of 5.5 (range 1-30) years. METHODS: Cough reflex sensitivity testing (C5; citric acid) was performed in all patients before fully ambulatory day-time and night-time cough recordings. Patients scored the frequency and severity of their cough (Visual Analogue Scales (VAS) and 0-5 score) for each recording period and completed a cough-related quality-of-life questionnaire, Leicester Cough Questionnaire (LCQ). Ambulatory cough recordings were manually counted and reported in terms of cough seconds per hour (cs/h). Cough rates were log(10) transformed for analysis. RESULTS: The median time spent coughing was 11.36 (range 1.06-46) cs/h with median day rates of 15.59 (range 2-74.8) cs/h and median night rates of 2.94 (range 0-26.67) cs/h. An inverse relationship was seen between day cough rates and log(10) C5 (r = -0.452, p< or =0.001). Subjective cough scores and visual analogue scales were only moderately associated with objective time spent coughing, with night-time being scores more strongly associated than day-time scores. The strongest correlation with objective cough frequency was cough-related quality of life (LCQ), (r = -0.622, p< or =0.001), mediated through the psychological domain. CONCLUSIONS: Subjective measures of cough and cough reflex sensitivity are only moderately related to objective time spent coughing, and hence cannot be used as surrogate markers for objective cough-frequency measurements. Cough-related quality of life (LCQ) is most strongly related to objectively counted cough, and may be a useful adjunct to objective measures in the assessment of cough.

Chronic Disease↗

Enhanced cough response to hyperpnea with cold air challenge in chronic cough patients showing increased cough sensitivity to inhaled capsaicin.

BACKGROUND: Although many chronic cough patients have complained of an induced cough by cold air contact, the clinical relevance of cold air to inducing a cough and the diagnostic value of a hyperpnea with cold air (HCA) challenge to detect a hyperreactive cough reflex have not yet been investigated. METHODS: Recordings of cough counts after a 2-min HCA challenge were performed in 49 chronic cough patients and 15 healthy controls. Capsaicin cough provocation tests, which determine the threshold concentration of capsaicin that induces five or more consecutive coughs (C5), were also administered. RESULTS: After comparing the results from the capsaicin cough provocation tests of the patients and the controls, the chronic cough patients were divided into two groups: an increased cough sensitivity (ICS) group (n = 28) (C5 < 32 micromol/l) and a normal cough sensitivity (NCS) group (n = 21) (C5 >or= 32 micromol/l). The median value of induced cough counts after a HCA challenge was 11 coughs in patients with ICS and was a significantly enhanced cough response compared to that of the patients with NCS and healthy controls (four coughs, respectively). CONCLUSIONS: A simple cough provocation test using a HCA challenge may be useful for detecting ICS. It also suggests that hyperreactive cough reflexes may be one of the mechanisms of inducing chronic cough.

Administration, Inhalation↗

Habit cough, tic cough, and psychogenic cough in adult and pediatric populations: ACCP evidence-based clinical practice guidelines.

OBJECTIVES: To review the literature on habit, tic, and psychogenic cough, and to make evidence-based recommendations regarding diagnosis and treatment. DESIGN/METHODOLOGY: For data on adults, an Ovid MEDLINE literature review (through February 2005) was performed for all studies published in the English language, including case series and case reports, since 1966 using the medical subject heading terms "habit cough," "psychogenic cough," "tic disorder," "vocal tic," "Tourette's syndrome," "honking cough," and "barking cough." For pediatric data, articles were identified dating from 1966 from searches of the Cochrane Library, PubMed, EMBASE, the list of references in relevant publications, and the authors' collection of references with the last search performed in February 2005. The search terms used were "children" and "vocal tics" or "habit cough," or "psychogenic cough" or "chronic cough." RESULTS/CONCLUSIONS: The methodologies used and rigor of the diagnostic and therapeutic interventions reported in the literature are inconsistent. The putative clinical characteristics of habit cough and psychogenic cough, for the most part, have not been prospectively or systematically studied. Therefore, on the basis of expert opinion, the diagnoses of habit cough or psychogenic cough can be made only after an extensive evaluation is performed that includes ruling out tic disorders and uncommon causes of chronic cough, and when cough improves with behavior modification or psychiatric therapy. In adult patients with chronic cough that remains persistently troublesome despite an extensive and thorough evidence-based evaluation, and after behavior modification and/or psychiatric therapy have failed, unexplained cough should be diagnosed rather than habit cough or psychogenic cough. In children, the depth of investigations to rule out uncommon causes must be individualized as some investigations and/or treatment may increase morbidity. In adult and pediatric patients with chronic cough that is associated with troublesome psychological manifestations, psychological counseling or psychiatric intervention should be encouraged after other causes have been ruled out.

Cough↗

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.

Adult↗

Comparison of atopic cough with cough variant asthma: is atopic cough a precursor of asthma?

BACKGROUND: We have described a group of patients who present with isolated chronic bronchodilator resistant non-productive cough with an atopic constitution, eosinophilic tracheobronchitis, and airway cough receptor hypersensitivity without bronchial hyperresponsiveness, which we have termed "atopic cough". Although cough variant asthma (in which the cough responds to bronchodilators) is recognised as a precursor of typical asthma, it is not known whether atopic cough is also a precursor of asthma. METHODS: Eighty two patients with atopic cough were retrospectively examined for onset of typical asthma and compared with 55 patients with cough variant asthma (20 untreated patients and 35 treated with long term inhaled beclomethasone dipropionate (BDP), 218-467 micro g/day). The median follow up period for patients with atopic cough and cough variant asthma was 4.8 (1-11.5) years and 3.7 (1-12.4) years, respectively. RESULTS: Onset of typical asthma occurred in only one of the patients with atopic cough. In patients with cough variant asthma, typical asthma developed in two of 35 patients taking BDP and six of 20 untreated patients (difference 24.3%, 95% CI 2.8 to 45.8, p<0.02). CONCLUSIONS: These findings suggest that cough variant asthma is a precursor of typical asthma but that atopic cough is not. Treatment with inhaled steroids may prevent the transformation of cough variant asthma into typical asthma.

Administration, Inhalation↗

Importance of atopic cough, cough variant asthma and sinobronchial syndrome as causes of chronic cough in the Hokuriku area of Japan.

OBJECTIVE: A prospective multicentre study was conducted to elucidate the causes of chronic cough in Japan. METHODOLOGY: All consecutive and unselected patients complaining of cough lasting 8 weeks or more, who visited our clinics from 1 June to 31 December 2001, were registered. The causes of chronic cough were diagnosed based on the criteria for definite and probable causes of cough as recommended by the Japanese Cough Research Society. RESULTS: Of the 248 patients enrolled, 72 patients (29.0%) were unavailable for follow up before their diagnostic assessment had been finalized. Among the 176 patients who were adequately assessed, a diagnosis was made in 165 patients (93.7%) either as single cause or as one of two causes: atopic cough in 48 (29.1%) and 11 patients (6.7%); cough variant asthma in 46 (27.9%) and nine patients (5.5%); cough predominant asthma in 14 (8.5%) and three patients (1.8%); and sinobronchial syndrome (SBS) in 28 (17.7%) and 14 patients (8.5%), respectively. A diagnosis of gastro-oesophageal reflux-associated cough was made in a total of four patients (2.4%). CONCLUSION: Atopic cough, asthmatic cough consisting of cough variant asthma and cough predominant asthma, and SBS are major causes of chronic cough in Japan.

Adolescent↗

Cough and gastroesophageal reflux: identifying cough and assessing the efficacy of cough-modifying agents.

From a symptom research standpoint, much has been learned about the management of cough in general and cough caused by gastroesophageal reflux disease in particular. Yet, before further advances can be made in our understanding of how to best manage patients with this common symptom, methodologic challenges remain to be solved. One of the most basic is the development of valid and reliable methods by which to identify cough, assess its impact on patients, and assess the efficacy of cough therapies. Herein, we review the characteristics of cough that relate to its assessment and how the effect of drug treatment on cough has been assessed. Perspective is provided on evaluating the efficacy of cough-modifying agents and the optimal method for identifying a cough and linking it with a reflux event. Investigators should use both subjective and objective methods, because they have the potential to measure different aspects of cough. Subjective measures, such as a cough-specific quality-of-life instruments, are likely to best reflect the severity of cough from the patient's standpoint, because a subjective response most likely integrates both cough frequency and intensity. The ideal objective method should allow cough to be automatically counted over 24 hours in an ambulatory setting. Although it is theoretically possible to design and construct such a device that is also relatively unobtrusive, reliable, and accurate, one is not yet available.

Antitussive Agents↗

Candesartan cilexetil is not associated with cough in hypertensive patients with enalapril-induced cough. Multicentre Cough Study Group.

The aim of this study was to evaluate the occurrence of dry cough during treatment with candesartan cilexetil, enalapril, or placebo in patients with hypertension and a history of angiotensin converting enzyme (ACE)-inhibitor-related cough. Patients with confirmed cough during an enalapril (10 mg) challenge period, followed by no cough during a placebo dechallenge period were randomized to 8 weeks of double-blind treatment with candesartan cilexetil (8 mg) (n = 62), enalapril (10 mg) (n = 66), or placebo (n = 26). Incidence and severity of dry cough was evaluated by the symptom assessment questionnaire, frequency of dry cough by a visual analog scale, and the possible impact on quality of life by the minor symptom evaluation (MSE) profile. The percentage of patients with cough was significantly lower with candesartan cilexetil (35.5%) than with enalapril (68.2%, P < .001), and did not differ between candesartan cilexetil and placebo (26.9%, P > .20). Patients coughed less frequently and with less severe cough with candesartan cilexetil than with enalapril, and similarly with candesartan cilexetil and placebo. Changes in the MSE profile were minor, although candesartan cilexetil had better scores for contentment than placebo (P = .03), and also tended to be associated with better sleep than enalapril (P = .08). In hypertensive patients with ACE-inhibitor-induced cough, the incidence, frequency, and severity of dry cough was significantly lower with candesartan cilexetil than with enalapril, and no different from that found with placebo.

Adult↗

The combined cough frequency/severity scoring: a new approach to cough evaluation in clinical settings.

Cough assessment is an important component in the clinical evaluation of patients with respiratory and cardiovascular disorders (asthma, chronic obstructive lung disease, congestive heart failure, etc.). A dry bothersome cough is the most common adverse class effect of all angiotensin-converting enzyme inhibitors (ACE-I). The present study was aimed to determine the feasibility of a new combined frequency/severity cough scoring method in patients with ACE-I induced cough before and after their modification with aspirin addition. The study was designed to compare two different regimens of active treatment: intermediate (500 mg) versus low (100 mg) dose aspirin in ACE-I cough suppression (self-matched control data) and comprised 21 patients (14 men, 7 women; mean age 62 +/- 11 years) on ACE-I treatment. ACE-I treatment was discontinued and the dry cough completely disappeared, but returned in all patients within one week (rechallenge period) after ACE-I reintroducing. Severity of cough was defined as follows: 0--no cough at all; 1--occasional hems; 2--mild, isolated cough, without additional symptoms; 3--moderate, paroxysmal cough, without additional symptoms; 4--severe, strenuous cough, accompanied by chest discomfort. In addition to cough severity score, cough frequency score (0-10) was obtained using a visual analog scale: 0 = I never cough; 10 = I cough all day. Low doses of aspirin were ineffective to suppress ACE-I induced cough. In contrast, intermediate doses completely abolished cough in 14 patients and reduced coughing in all but one patient. Cough severity and cough frequency scores decreased, respectively, from 2.6 +/- 1.1 to 0.7 +/- 1.0 (p<0.001) and from 6.9 +/- 2.2 to 2.1 +/- 2.4 (p<0.0001). Overall, the cough frequency score method alone could identify a beneficial modification of cough in 17 (81%) patients and cough severity score method alone in 17 (76%). Using the combined cough frequency/severity scoring, a beneficial modification of cough could be identified in 20 (95%) of patients. The new combined cough frequency/severity scoring is suitable for clinical practice and can improve the identification of dynamic cough modifications during treatment period as compared with the conventional frequency score method. It may have important implications in the evaluation of patients with respiratory and cardiovascular disorders.

Aged↗

Cough, cough receptors, and asthma in children.

This review discusses current general concepts on cough and the relationship between cough, cough receptor sensitivity, and asthma in children. It presents models of the relationship between cough and bronchoconstriction, and proposes a new model outlining the relationship between cough receptor sensitivity, airway hyperresponsiveness, and the clinical issues of cough, wheeze, and dyspnea in children with and without asthma. Cough is very common in children, with a prevalence of 15-20%. Those with non-specific cough (dry cough in the absence of identifiable respiratory illness) are often treated with a variety of drugs, in particular, medications for asthma and gastroesophageal reflux. However, there is little evidence to use these medications for the sole symptom of cough in children. Clinical studies on cough need to be interpreted in light of inherent methodological problems in studying cough. These methodological problems include the nonrepeatable nature of questions on cough, the unreliability of subjective measurements of cough, the lack of objective measurements to quantify cough severity, and the period effect (spontaneous resolution of cough). Although cough can be troublesome, cough serves as an important function for maintaining normal health of the respiratory system. The importance of cough in maintaining respiratory health is reflected in the development of lung atelactasis/collapse from retained secretions and recurrent pneumonia in clinical situations where the cough reflex is ineffective. The cough reflex is complex and still poorly understood. In this article the simplified cough pathway is presented and involves cough receptors, mediators of sensory nerves and the afferent pathway, the vagus nerve, the cough centre, efferent pathway, and cough effectors.

Adolescent↗

Cough in COPD: correlation of objective monitoring with cough challenge and subjective assessments.

BACKGROUND: The relationships between objective cough rates, cough reflex sensitivity, subjective estimates of cough frequency, and cough-related quality of life in patients with COPD are poorly understood. SUBJECTS: Twenty-six patients with stable COPD who complained of cough (76.9% men; mean +/- SD age, 68.7 +/- 6.9 years; mean FEV(1), 54.2 +/- 12.0% of predicted; median smoking history, 42.4 pack-years [range, 13 to 135 pack-years]). METHODS: Subjects performed a cough challenge test, ambulatory daytime and overnight sound recordings, scored the severity of cough (0 to 5 score and visual analog scale) for each recording period, and completed a cough-specific quality of life questionnaire (CQLQ). Coughs were counted manually and quantified in terms of cough seconds per hour (cs/h): the number of seconds within the recording that contain cough. RESULTS: Overall median time spent coughing was 7.5 cs/h (range, 2.7 to 23.1 cs/h; daytime median, 12.4 cs/h [range, 3.3 to 40.4 cs/h]; overnight, 1.9 cs/h [0.0 to 19.0 cs/h]) [p = <0.01]. Median log concentration of citric acid eliciting five coughs (C5) was - 0.9 mol/L (range, - 1.5 to 0.0 mol/L). Day time but not overnight time spent coughing was significantly correlated with log C5 (log C5 r = - 0.49, p = 0.02, and r = - 0.20, p = 0.37, respectively). Subjective cough scores and visual analog scales were moderately associated with objective time spent coughing: daytime (r = 0.37, p = 0.03, and r = 0.41, p = 0.03) and overnight (r = 0.48, p = <0.01, and r = 0.5, p = 0.01), respectively. CONCLUSIONS: Subjective measures of cough and cough reflex sensitivity are statistically related to time spent coughing in patients with COPD, but with low-to-moderate levels of correlation. These measures have insufficient predictive value to substitute for objective time spent coughing; however, in conjunction with the CQLQ, they may provide a qualitative dimension to the assessment of cough.

Aged↗

A Comparison of the Cough Profile of Fosinopril and Enalapril in Hypertensive Patients with a History of ACE Inhibitor-Associated Cough.

OBJECTIVE: Cough frequency and severity with fosinopril and enalapril were assessed in hypertensive patients with previous angiotensin-converting enzyme inhibitor (ACEI)-associated cough. DESIGN: Prospective, multicenter, randomized, 8-week double-blind treatment. PATIENTS: One hundred seventy-nine patients (mild-to-moderate hypertension, nonsmokers, mean age 58 years; 55% females; 72% Caucasian, 6% black, 19% Hispanic) were studied. Patients with other cough etiologies, significant co-morbidity, or confounding medications were excluded. INTERVENTIONS: Patients were randomized to fosinopril 10 mg (n = 85) or enalapril 5 mg (n = 94) once daily. Dosage could be doubled for blood pressure control after 4 weeks. Outcome measurements: The primary end point was all-cough frequency based on patient daily diary ratings; a cumulative cough frequency score was calculated. Secondary end points included cough severity, nonproductive cough frequency, night awakenings, cough time of day, and spontaneously reported cough. RESULTS: Fosinopril and enalapril demonstrated similar blood pressure control. Significant cough profile differences were observed in favor of fosinopril: all-cough frequency was 40.6 plus minus 3.8 (mean plus minus SE) versus 52.8 plus minus 3.6 (p = 0.02); nonproductive cough frequency was 26.7 plus minus 3.5 versus 40.3 plus minus 3.4 (p less-than-or-equal 0.01); and cough time of day was 49.2 plus minus 5.2 versus 66.0 plus minus 5.0 (p = 0.02), for fosinopril and enalapril, respectively. Subgroup analysis revealed all-cough frequency was 33.5 plus minus 6.3 versus 56.6 plus minus 5.3 (p = 0.006) for fosinopril and enalapril, respectively, in patients who previously had cough on one of these two ACEI (predominantly enalapril). Ten (12%) fosinopril and 25 (27%) enelapril patients spontaneously reported cough (p = 0.01). CONCLUSIONS: Hypertensive patients with previous ACEI-associated cough reported less frequent cough with fosinopril compared to enalapril, based on cumulative patient diary scores and spontaneously reported cough. This difference was most apparent in the subgroup of patients who previously experienced cough associated with enalapril therapy. Patients with prior ACEI-associated cough may experience less frequent with fosinopril.

Journal Article↗

Capsaicin cough sensitivity decreases with successful treatment of chronic cough.

To assess the role of enhanced cough sensitivity in the pathogenesis of cough, we measured cough severity on a visual analogue scale (VAS) and capsaicin cough sensitivity (the concentration required to elicit two [C2] and five [C5] coughs) in 87 consecutive patients referred with chronic cough. Measurements were repeated after complete investigation and treatment, when patients were entered into one of four study groups: (1) treatment success (primary cause of cough successfully treated with elimination of the cough, n = 48); (2) primary treatment failure (treatment of potential primary cause of cough unsuccessful, n = 12); (3) cough treatment failure subgroup A (potential primary cause of cough identified and successfully treated but no improvement in cough, n = 8); and (4) cough treatment failure subgroup B (no potential primary cause of cough identified, n = 19). All patients in groups 3 and 4 were nonsmokers, had normal chest radiography and negative histamine challenge test, and failed to respond to intensive empirical treatment for rhinitis and gastroesophageal reflux. The VAS cough severity was lower and log C2 and C5 higher after treatment compared with initial values in the treatment success group but not in the other three groups. Enhanced sensitivity of airway nerves that mediate cough is important in the pathogenesis of nonproductive cough, and successful treatment is associated with a reduction in cough sensitivity. While enhanced sensitivity of airway nerves is usually present in patients with identifiable causes of chronic nonproductive cough, it is also found in other patients in whom the cause of cough is unknown.

Adult↗

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

Tonsillar enlargement is sometimes seen in patients with otherwise unexplained chronic cough although its significance is unclear. In this study, the authors set out to test the hypothesis that cough symptoms and cough reflex sensitivity will improve after tonsillectomy in patients with otherwise unexplained chronic cough and enlarged tonsils. Eight consecutive patients with unexplained chronic cough and enlarged tonsils were recruited from 236 patients seen in a cough clinic between 2000 and 2001. Six patients with enlarged tonsils and no cough who were undergoing tonsillectomy for other reasons were recruited as a control group. All patients rated cough severity on a cough visual analogue score (0-100 mm) and had capsaicin cough reflex sensitivity measurement twice before and again 3 months after tonsillectomy. Patients with a chronic cough had heightened cough reflex sensitivity compared with the control group at baseline. There was a significant improvement in mean cough visual analogue score 3 months after tonsillectomy in patients with chronic cough (mean difference 30 mm; 95% confidence interval of difference 8-51 mm). The geometric mean concentration of capsaicin required to cause five coughs increased from 4 to 207 micromol L(-1) after tonsillectomy in patients with chronic cough (mean difference from baseline 5.6 doubling concentrations; 95% confidence interval of difference 3.1-8.2). There was no change in cough reflex sensitivity in control patients after tonsillectomy. These preliminary findings suggest for the first time a possible role for tonsillectomy in patients with enlarged tonsils in whom other causes of cough have been ruled out.

Administration, Inhalation↗

Cough sensitivity and extrathoracic airway responsiveness to inhaled capsaicin in chronic cough patients.

Enhanced cough response has been frequently observed in chronic cough. Recently, extrathoracic airway constriction to inhaled histamine was demonstrated in some chronic cough patients. However, relation between extrathoracic airway hyperresponsiveness (EAHR) and cough sensitivity determined by capsaicin inhalation is unclear in each etiological entity of chronic cough. Seventy-seven patients, with dry cough persisting for 3 or more weeks, normal spirometry and chest radiography, and 15 controls, underwent methacholine bronchial provocation test and capsaicin cough provocation test. Elicited cough number and flow-volume curve was examined after inhalation of capsaicin to evaluate cough sensitivity and EAHR. Thirty-three patients, with postnasal drip, showed normal extrathoracic airway responsiveness, and 27 of them showed normal cough sensitivity to capsaicin. Cough sensitivity was enhanced in 14 patients with cough variant asthma (CVA) who showed bronchial hyperresponsiveness; EAHR to inhaled capsaicin was present in 12 of them. The remaining 30 patients were tentatively diagnosed as idiopathic chronic cough (ICC). Eleven ICC patients showed enhanced cough sensitivity and EAHR to inhaled capsaicin while 19 patients showed normal values. These results indicate that cough sensitivity is closely related with extrathoracic airway responsiveness during capsaicin provocation in some chronic cough patients. EAHR and enhanced cough sensitivity to inhaled capsaicin may be a part of mechanism developing chronic cough.

Administration, Inhalation↗

Coughing frequency in patients with persistent cough: assessment using a 24 hour ambulatory recorder.

Cough is an important symptom of many respiratory disorders. We determined the frequency and diurnal variation of cough in normal subjects and in patients with asthma or with persistent cough of unknown cause. We used a portable, solid-state, multiple-channel recorder to record cough sounds over a 24 h period. The audio-signal was recorded from a unidirectional microphone strapped over the chest wall, and electromyographic (EMG) signals from the lower respiratory muscles were simultaneously registered with surface electrodes. The recorded digital data were examined on an IBM-compatible computer, and the typical signals induced by cough (as assessed by voluntary or experimentally-induced cough) were counted. In 12 normal subjects, only 0-16 coughs were recorded over 24 h. In 21 stable asthmatics with a history of chronic cough ("asthma") the median number was 282 (ranges: 45-1,577), and in 14 patients with the predominant symptom of daily dry coughs ("chronic coughers") the median number was 794 (64-3,639). In both groups of patients, there was a diurnal variation of coughs, such that the least numbers occurred between 2 and 5 a.m. (< 3% of total). In the asthma group, there was no significant correlation between forced expiratory volume in one second (FEV1) (% predicted) or diurnal variation of peak expiratory flow and cough frequency. In the chronic coughers, there was a significant correlation between daytime cough numbers and daytime cough symptoms scores but not for the night-time values. Our data show that cough frequency is not determined by the severity of asthma in relatively stable asthmatics on inhaled steroids, and is reduced during sleep in both asthmatics and chronic cough patients. This portable cough recorder may be useful in the assessment of drug therapy for chronic cough.

Adult↗

The effect of sulindac on the abnormal cough reflex associated with dry cough.

In order to determine the possible role of prostaglandins in the abnormal cough reflex in patients with dry cough, the effects of a cyclooxygenase inhibitor on cough symptoms were examined. This was measured by a cough symptom score and by the cough reflex sensitivity to inhaled capsaicin in a double blind, randomized, cross-over study comparing the effects of placebo with sulindac, 200 mg daily for 1 week. We studied six hypertensive patients with angiotensin converting enzyme inhibitor-associated cough and six patients with an idiopathic, dry, unproductive cough, all of whom had an increase in the sensitivity of the cough reflex. There was no change in blood pressure control in the hypertensive patients during sulindac therapy. The patients with the angiotensin converting enzyme-associated cough had a significant reduction in the cough symptom score and also a significant increase in the dose of capsaicin causing two or more coughs (threshold sensitivity) and that causing five or more coughs (near maximum response) during sulindac therapy as compared to placebo. In those patients with idiopathic, dry, unproductive cough, sulindac did not alter the symptom of cough or the cough reflex response to capsaicin. These results suggest that prostaglandins may be involved in cough associated with angiotensin converting enzyme inhibitor therapy, but are less likely to be important in the pathogenesis of more common dry coughs of unknown cause.

Aged↗