How Has the management of cough changed.ppt [Read-Only]


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How Has the management of cough changed.ppt [Read-Only]

  1. 1. 1 How Has The Management OfHow Has The Management Of Cough Changed?Cough Changed? Presented by: Richard S. Irwin, MD, FCCP Professor of Medicine and Nursing Dates of Historical ImportanceDates of Historical Importance in the Management of Coughin the Management of Cough  1977 – A comprehensive review of cough was published Arch Intern Med 1977; 137: 1186-1191 – Introduced the concept of a systematic diagnostic approach Neuroanatomic diagnostic approach Emphasized the potential importance of extrapulmonary causes – Beginning of the modern era Dates of Historical ImportanceDates of Historical Importance in the Management of Coughin the Management of Cough  1998 – The 1st evidence-based clinical practice guideline on managing cough was published  CHEST 1998; 114, Supplement: 133S-181S – The impetus for its publication was the recognition of the importance of cough in clinical medicine  Cough was the most common complaint for which patients seek medical care in the US  The estimated annual aggregate cost of treating cough exceeded $1 billion in the US  The writing Committee was international in composition – Australia, Canada, UK, US • ACCP, ACP, ATS, CTS  Confirmed the importance of a systematic diagnostic approach and extrapulmonary causes
  2. 2. 2 Dates of Historical ImportanceDates of Historical Importance in the Management of Coughin the Management of Cough  2006 – A revised clinical practice guideline on managing cough will be published in January, 2006  CHEST 2006; in press – The impetus for its publication was  Appreciation of the continuing importance of cough in clinical medicine in the US and globally – Most common complaint for which patients seek medical care in the US and Australia – The annual aggregate cost of treating cough is now estimated to exceed $3 billion in the US  Acknowledgement that advances had taken place since 1998  The writing Committee was international in composition and utilized a more rigorous process than in 1998 – Australia, Canada, UK, US • Sponsoring Societies: ACCP, ATS, CTS – Unanimously agreed upon the definitions of acute, subacute, chronic cough Which Of The Highlights Represent Changes In Management Since 1998? Highlights of the ACCP RevisedHighlights of the ACCP Revised Cough CPGCough CPG Unexplained CoughLung TumorsUpper Airway Cough Syndrome Evaluating Cough in Pediatrics Occupational/Environmental Considerations in Cough Chronic Bronchitis Nonpharmacologic Airway Clearance Therapy Chronic Interstitial Pulmonary Disease Acute Bronchitis Suppressant/Protussive Pharmacologic Therapy Habit/Tic/Psychogenic Cough GERD Assessing CoughACEI-induced CoughAsthma Empiric Diagnostic Approach Aspiration 2nd DysphagiaCommon Cold Uncommon CausesPostinfectious CoughCommon Causes of Chronic Cough in Adults Immunocompromised Host and Cough Non-bronchiectatic Suppurative Airway Disease Complications Peritoneal DialysisBronchiectasisPhysiology/Pathophysiology TB and Other InfectionsNonasthmatic Eosinophilic Bronchitis Anatomy/ Neurophysiology
  3. 3. 3 Complications of CoughComplications of Cough  The complications appear to stem from physiological events. The magnitude of pressures, velocities, energy generated during vigorous coughing can cause a variety of profound physical and psychosocial complications including ↓ HRQoL – Intrathoracic pressures up to 300 mm Hg – Expiratory velocities up to 28,000 cm/s or 500 miles/hour (85% of the speed of sound) – Intrathoracic energies of 1 to 25 J  Knowledge of the spectrum of complications should enable clinicians to appreciate – The impact of cough on patients – Why it is imperative to exhaust all efforts to eliminate cough Commonest Causes ofCommonest Causes of Chronic Cough in AdultsChronic Cough in Adults  A review of 11 series of chronic coughers, with at least 39 subjects, from around the globe revealed a remarkably constant composite picture – In the vast majority, chronic cough has been due to upper airway cough syndrome (UACS) due to a variety of rhinosinus conditions, asthma, and gastroesophageal reflux disease (GERD)  In 5 prospective studies from the western hemisphere, these 3 diseases singly or in combination caused 92-96% of the chronic coughs in non-smokers who were not on ACE inhibitors and who had normal chest radiographs. Chronic bronchitis and bronchiectasis caused ~ 4-8%  The prevalence of non-asthmatic eosinophilic bronchitis (NAEB) as a cause outside of the western hemisphere has ranged from 0 to 33%  UACS, asthma, GERD, and NAEB are the commonest – Even where TB is endemic – History is non-specific; each can present solely with cough Chronic Upper AirwayChronic Upper Airway Cough SyndromeCough Syndrome  The Committee unanimously recommends that the term “upper airway cough syndrome” (UACS) be used in preference to “postnasal drip syndrome” when discussing cough associated with upper airway conditions because – It is unclear whether the mechanism(s) of cough is postnasal drip or direct irritation or inflammation of the cough receptors in the upper airway
  4. 4. 4 Chronic Upper AirwayChronic Upper Airway Cough SyndromeCough Syndrome  UACS secondary to a variety of rhinosinus conditions is the most common cause of chronic cough – Because the signs and symptoms are non-specific, a definitive diagnosis cannot be made from history and physical alone  GERD may occasionally mimic UACS  In 20% of cases, patients are unaware of upper airway symptoms – Diagnosis of UACS is determined by considering a combination of symptoms, physical, sinus imaging studies, and ultimately response to specific therapy  Sinusitis can be clinically silent Chronic Upper AirwayChronic Upper Airway Cough SyndromeCough Syndrome  In patients in whom the cause of UACS is apparent, specific therapy directed at this condition should be instituted.  For patients with chronic cough of unknown etiology, an empiric trial of therapy for UACS should be administered first because UACS is the most common cause of chronic cough. – Unless contraindicated, use a 1st generation antihistamine-decongestant  If patients don’t respond to this, next order a sinus imaging study because UACS can be due to silent sinusitis Cough and the Common ColdCough and the Common Cold  Based upon extrapolation from epidemiological data, the common cold is believed to be the most common cause of acute cough. – The most likely mechanism is direct irritation of upper airway structures  It is therefore considered an acute UACS – It is clear that viral infections of the upper respiratory tract that produce the common cold syndrome frequently produce a rhinosinusitis  The abnormalities on sinus imaging studies are frequently due to viral not bacterial infection – For treatment, the Committee recommends  1st generation antihistamine/decongestant therapy or NSAIDs – “Non-sedating” antihistamines appear to be ineffective  The diagnosis of bacterial sinusitis should not be made during the 1st week of symptoms
  5. 5. 5 AsthmaAsthma  Cough is usually associated with the more typical symptoms of dyspnea and wheezing – In a subgroup, cough is the predominant or sole symptom (Cough-variant asthma)  When suspecting cough due to asthma but physical and spirometry are nondiagnostic, methacholine challenge should be performed to confirm the presence of asthma – However, a diagnosis of asthma as the cause of cough is established only after resolution of cough with specific therapy. – If methacholine challenge cannot be performed, empiric therapy should be given; however, a favorable response to steroids will not exclude NAEB. AsthmaAsthma  Patients with cough due to asthma should be initially treated with a standard antiasthma regimen of inhaled bronchodilators and corticosteroids – When refractory to this regimen, an assessment of airway inflammation should be performed whenever available and feasible. Demonstration of persistent airway eosinophilia suggests the need for more aggressive anti- inflammatory therapy A leukotriene receptor antagonist may be added before escalation to systemic corticosteroids GERDGERD  In patients with chronic cough due to GERD, the term acid reflux disease, unless it can be shown to apply, should be replaced by the more general term reflux disease so as not to mislead the clinician into believing that all patients with cough due to GERD should improve with acid-suppression therapy. – In patients with normal chest radiographs, GERD most likely causes cough by stimulation of an esophageal- bronchial reflex. – When GERD causes cough, there may be no GI symptoms up to 75% of the time. – While 24-hour esophageal pH monitoring is the most sensitive and specific test in linking GERD and cough in a cause and effect relationship, it has limitations.  There is lack of agreement on how to best interpret the test  It cannot detect non-acid reflux events
  6. 6. 6 GERDGERD  Empiric anti-reflux therapy should be prescribed for patients with chronic cough who – have GI symptoms consistent with GERD or – fit a specific clinical profile of having “silent” GERD  Profile of patient with chronic cough due to GERD: – Chronic cough – Not exposed to environmental irritants nor smoke – Not taking an ACEI – Chest radiograph is normal or near normal and stable – Symptomatic asthma has been ruled out – UACS has been ruled out – NAEB has been ruled out GERDGERD  For treating the majority of patients with chronic cough, the following medical therapies are recommended: – Dietary and lifestyle modifications – Acid suppression therapy, and – The addition of prokinetic therapy either initially or if there is no response to the 1st two therapies – The response to these therapies should be assessed within 1 to 3 months.  When this empiric regimen fails, it cannot be assumed that GERD has been ruled out as a cause of chronic cough; rather, objective investigation for GERD is then recommended because – empiric therapy may not have been intensive enough – medical therapy may have failed – surgery may be considered Acute BronchitisAcute Bronchitis  Acute bronchitis has been the term used for an acute respiratory infection manifested predominantly by cough with or without phlegm production that lasts for up to 3 weeks. – It is one of the most common diagnoses made by primary care and emergency department physicians. – Unfortunately, most controlled trials have not vigorously or consistently differentiated the acute cough due to acute bronchitis from the common cold, acute exacerbation of chronic bronchitis, or acute asthma.  A diagnosis of acute bronchitis should not be made unless there is no clinical or radiographic evidence of pneumonia, and the common cold, acute asthma, or an exacerbation of COPD have been ruled out as the cause of cough.  For patients with a putative diagnosis of acute bronchitis, routine treatment with antibiotics is not justified and should not be offered.
  7. 7. 7 Chronic BronchitisChronic Bronchitis  Adults who are exposed to airway irritants and who have a history of chronic cough and sputum expectoration occurring on most days for at least 3 months and for at least 2 consecutive years should be given a diagnosis of chronic bronchitis when other respiratory or cardiac causes of chronic productive cough are ruled out.  When a stable patient suddenly experiences a sudden clinical deterioration with increased sputum volume, sputum purulence and/or worsening of shortness of breath, this is referred to as an acute exacerbation of chronic bronchitis, as long as conditions other than acute tracheobronchitis are ruled out. Chronic BronchitisChronic Bronchitis  The most effective way to reduce or eliminate cough is avoidance of personal tobacco use, passive smoke exposure, and other environmental irritants. – Cough can persist in patients with the worst lung function  For stable patients: – Short-acting inhaled Β agonists, inhaled ipratropium, oral theophylline and combined inhaled long-acting Β agonists and inhaled corticosteroids may improve cough – There is no proven benefit with prophylactic antibiotics, oral corticosteroids, expectorants, and chest PT.  For an acute exacerbation: – There is evidence that inhaled bronchodilators (Β agonist and/or ipratropium), oral antibiotics, and oral or in severe cases IV corticosteroids are useful but their effects on cough have not been systematically evaluated. – Expectorants, postural drainage, chest PT, and theophylline are not recommended. Non-AsthmaticNon-Asthmatic EosinophilicEosinophilic BronchitisBronchitis  Non-asthmatic eosinophilic bronchitis is characterized by the presence of eosinophilic airway inflammation, similar to that seen in asthma. – In contrast to asthma, non-asthmatic eosinophilic bronchitis is not associated with variable airflow limitation or airway hyperresponsiveness. – Recent evidence suggests that the differences in functional associations are related to differences in localization of mast cells within the airway wall  There is smooth muscle infiltration in asthma  There is epithelial infiltration in non-asthmatic eosinophilic bronchitis
  8. 8. 8 Non-AsthmaticNon-Asthmatic EosinophilicEosinophilic BronchitisBronchitis  The diagnosis should be considered in patients with chronic cough who have normal chest radiographs, normal spirometry, and no evidence of airway hyperresponsiveness. – Diagnosis is made by the confirmation of eosinophilic airway inflammation usually in induced sputum analysis after exclusion of other causes of chronic cough on clinical, radiological, and lung function assessment.  The cough usually responds well to inhaled corticosteroids – The dose and duration of treatment differ between patients – When a causal allergen or occupational sensitizer is identified, avoidance is the best treatment  The condition can be transient, episodic, or persistent unless treated; occasionally, patients my require long- term prednisone therapy. BronchiectasisBronchiectasis  Bronchiectasis is characterized by permanent dilation of bronchi with destruction of elastic and muscular components of their walls, usually due to acute or chronic infection/inflammation.  It can be the cause of chronic cough 0-4% of the time. – While chronic productive cough is the cardinal feature of bronchiectasis, this symptom occurs far more commonly in chronic bronchitis, UACS, asthma, and GERD.  Most cases in adults are idiopathic; however, in the absence of an obvious cause, a diagnostic evaluation for an underlying disorder will reveal such a disorder up to 47% of the time and treatment for the underlying disorder may slow or halt the progression of airway disease up to 15% of the time.  In patients with suspected bronchiectasis without a characteristic chest radiograph, HRCT is the diagnostic procedure of choice (specificity and sensitivity > 90%). BronchiectasisBronchiectasis  With respect to treatment: – Bronchodilators including anticholinergics, and oral and inhaled steroids are often used in stable bronchiectasis as well as during acute exacerbations despite the lack of objective evidence of benefit. – In cystic fibrosis patients only, rhDNase should be used to improve spirometry. Its affect on cough has not been studied. – Antibiotics and bronchopulmonary hygiene are mainstays in the treatment of exacerbations but prolonged use of systemic and inhaled antibiotics cannot be recommended to prevent these episodes except in patients with cystic fibrosis.  CPT offers modest benefit in increasing sputum volume only – Surgery is beneficial in a carefully selected subgroup of patients with focal disease and intractable symptoms.
  9. 9. 9 Non-Non-BronchiectaticBronchiectatic SuppurativeSuppurative Airway DiseaseAirway Disease  Cough may be the initial manifestation, or develop during the clinical course, of non-bronchiectatic suppurative airway disease (bronchiolitis).  While infrequently encountered, these small airway disorders are seen commonly enough by the practicing pulmonologist to warrant serious consideration in the correct clinical setting (IBD, lived in SE Asia).  When the more common causes of cough have been ruled out, consider non-bronchiectatic suppurative airway diseases as the potential cause in patients with – Incompletely or irreversible airflow limitation, small airways disease on HRCT, or purulent secretions on bronchoscopy.  Direct signs: airway dilation or wall thickening; “tree-in-bud” pattern  Indirect signs: air-trapping (mosaic attenuation on expiration) – Successful management depends upon identification of the specific underlying disorder. Lung biopsy may be required. PostinfectiousPostinfectious CoughCough  Following an acute respiratory infection, when a patient complains of cough for at least 3 weeks, but not more than 8 weeks, consider the diagnosis of postinfectious cough. – Chest radiograph must be normal – If cough persists > 8weeks, consider other diagnoses – Always consider the possibility of B. pertussis infection in this setting  The diagnosis can be made clinically when cough is accompanied by paroxysms of coughing associated with post-tussive vomiting, and/or an inspiratory whooping sound (specifically ask about these)  In patients with subacute, postinfectious cough, because there are multiple pathogenetic factors that may contribute to cough, judge which factors are most likely provoking cough before considering therapy – Inflammation of the upper airway causing UACS – Transient inflammation of the lower airways causing airway hyperresponsiveness, mucus hypersecretion, retained secretions – GERD provoked by vigorous coughing  Except for bacterial sinusitis or early in B. pertussis infection, antibiotics have no role. Lung TumorsLung Tumors  Cough and productive cough are present in > 65% and > 25% of patients at the time lung cancer is diagnosed; yet, lung cancer is the cause of chronic cough in 0-2% of all patients who present with chronic cough. – In a patient with cough who has risk factors for lung cancer or a known or suspected cancer in another site that may metastasize to the lungs, a chest radiograph should be obtained. – Risk factors include heavy smoker with new onset cough; a change in the characteristics of a pre-existing cough; hemoptysis; exposure to passive cigarette smoke, asbestos, radon; COPD, and family history of lung cancer  In patients with a suspicion of airway involvement by a malignancy, even when the chest radiograph is normal, bronchoscopy is indicated.
  10. 10. 10 Cough From Aspiration Due toCough From Aspiration Due to Oral-PharyngealOral-Pharyngeal DysphagiaDysphagia  Cough is an important potential indicator of aspiration due to oral-pharyngeal dysphagia (abnormal swallowing). – Clinicians should have a high index of suspicion that aspiration is causing cough in patients at risk of oral-pharyngeal dysphagia (acute stroke [> 33%], cervical spine surgery [> 40%]) – Cough while eating may indicate aspiration; but, aspiration may be clinically silent – Patients with high-risk conditions should be referred for an oral- pharyngeal swallowing evaluation – Treatment of dysphagia patients by a multidisciplinary team including early evaluation by a speech-language pathologist is associated with improved outcomes – Patients with dysphagia should undergo videofluoroscopic or flexible endoscopic evaluation of swallow to identify appropriate treatment – Patients with a reduced level of consciousness are at high risk for aspiration and should not be orally fed until the level of consciousness has improved AngiotensinAngiotensin-Converting Enzyme-Converting Enzyme Inhibitor-Induced CoughInhibitor-Induced Cough  A dry, persistent cough is a well-described class effect of the ACEIs. The mechanism is unresolved but likely involves – The protussive mediators bradykinin and substance P that are normally degraded by ACE but that accumulate in the upper and perhaps lower respiratory tract when ACE is inhibited; and prostaglandin production that is stimulated by bradykinin. – The incidence ranges between 5-35% in blood pressure trials and 0-2% in patients who seek medical care because of chronic cough – The onset ranges from hours to months after initiation. Resolution typically occurs within 1-4 weeks after cessation of therapy, but may take 3 months AngiotensinAngiotensin-Converting-Converting Enzyme Inhibitor-Induced CoughEnzyme Inhibitor-Induced Cough  In patients presenting with chronic cough, in order to determine that the ACEI is the cause, ACEIs should be discontinued regardless of the temporal relation between the onset of cough and initiation of ACEI therapy.  In patients whose cough resolves after cessation of the ACEI, and for whom there is a compelling reason to treat with these agents, a repeat trial of ACEI may be attempted. – In a minority of patients, cough will not recur  In patients for whom cessation of ACEI therapy is not an option, continue the ACEI and attempt to ameliorate the cough with – Sodium cromoglycate, theophylline, sulindac, indomethacin, amlodipine, nifedipine, ferrous sulfate, or picotamide (thromboxane receptor antagonist [not available in US])  In patients with persistent or intolerable ACEI cough, therapy should be switched when indicated to an angiotensin receptor blocker (the incidence of cough is similar to control drugs), or to an appropriate agent of another drug class.
  11. 11. 11 Habit, Tic, andHabit, Tic, and PsychogenicPsychogenic CoughCough in Adult and Pediatric Populationsin Adult and Pediatric Populations  The methodology and rigor of the diagnostic and therapeutic interventions in the literature are inconsistent. The putative clinical characteristics of habit cough and psychogenic cough have not been prospectively or systematically studied. – On the basis of expert opinion, the diagnoses of habit or psychogenic cough can only be made after an extensive evaluation that includes ruling out tic disorders (including Tourette’s syndrome) and uncommon causes of chronic cough, and cough improves with behavior modification or psychiatric therapy. – In this setting, if chronic cough persists, adult patients should be diagnosed as having unexplained cough. – In children, the depth of investigations to rule out uncommon causes must be individualized as some investigations and/or treatment may increase morbidity. Chronic Interstitial PulmonaryChronic Interstitial Pulmonary DiseaseDisease  The chronic interstitial pulmonary diseases account for up to 15% of the patients seen by practicing pulmonologists. – The term combines a wide range of disorders that diffusely affect the lung parenchyma with variable amounts of inflammation (lymphocytic, neutrophilic, eosinophilic, granulomatous), fibrosis and architectural distortion. Chronic cough may be a presenting or complicating feature in all.  Prototypical diseases include IPF, sarcoidosis, and hypersensitivity pneumonitis  In IPF, clinically significant cough either due to IPF or a comorbid disorder occurs in more than 80% of patients  While the pathogenesis in these diseases is not known, in IPF, there is an associated ↑ sensitivity to capsaicin & sputum levels of nerve growth factor and brain-derived neurotropic factor suggesting a functional upregulation of sensory neurons of the lung Chronic Interstitial PulmonaryChronic Interstitial Pulmonary DiseaseDisease  In patients with chronic cough, before diagnosing chronic interstitial pulmonary disease as the sole cause, common etiologies such as UACS, asthma, and GERD should be considered. – The cause may be due to a diagnosis other than chronic interstitial pulmonary disease at least 50% of the time.  In patients with cough due to chronic interstitial pulmonary disease, primary treatment should be dictated by the specific disorder. – When there is no effective treatment for the interstitial lung disease, the diagnosis of chronic interstitial pulmonary disease as the sole cause of cough should be considered a diagnosis of exclusion.
  12. 12. 12 Occupational and EnvironmentalOccupational and Environmental Considerations in the Cough PatientConsiderations in the Cough Patient  Almost any patient with chronic cough may have an occupational or environmental cause or contribution to their cough.  Recognition and intervention may result in full or partial improvement of the cough, limit the need for medication/symptomatic therapy, and improve the long-term prognosis.  Non-occupational environmental contributing factors for upper and lower airway causes include – Indoor irritant and allergenic agents such as cigarette smoke, cooking fumes, animals, dust mites, fungi, and cockroaches. – Outdoor pollutants and allergens may also contribute  The diagnosis is only reached by initially considering possible occupational and environmental factors in every patient with cough and evaluating them by history followed by objective investigations. Chronic Cough Due to TBChronic Cough Due to TB and Other Infectionsand Other Infections  Chronic cough is the most common symptom of active TB.  Although tuberculosis and other lung infections are common throughout the developing world, they are not amongst the most common causes of chronic cough in these populations. – The Practical Approach to Lung Health (PAL) program , a WHO initiative to control TB and other respiratory diseases, found that only 1.5% of chronic coughs (2-3 weeks) were due to TB.  In patients with chronic cough who live in areas with a high prevalence of TB including prisons and nursing homes, this diagnosis should be considered but not to the exclusion of the more common etiologies.  In patients with unexplained cough who reside or have resided in areas of endemic infection with fungi and parasites, evaluations for these pathogens should also be considered. Peritoneal Dialysis and CoughPeritoneal Dialysis and Cough  Patients with end-stage renal disease on peritoneal dialysis are at increased risk of chronic cough. – The prevalence of chronic cough in peritoneal dialysis patients has been reported to be 22% compared to 7% in patients on hemodialysis. – Although both groups frequently receive medications which can potentially trigger cough such as ACEIs and Β blockers and both groups are at increased risk for fluid overload and pulmonary edema, the increased risk associated with peritoneal dialysis most likely relates to GERD that can be initiated or exacerbated by increased intraperitoneal pressures.  In patients on chronic peritoneal dialysis with chronic cough, evaluate the patient for the potential causes with increased prevalence in this population.
  13. 13. 13 Cough in theCough in the ImmunocompromisedImmunocompromised HostHost  In patient with immune deficiency, the initial diagnostic algorithm for patients with acute, subacute, and chronic cough is the same as for immunocompetent patients. – However, an expanded list of differential diagnoses should be taken into account that considers the type and severity of immune defect and geographic factors.  In HIV-infected patients, CD4+ lymphocyte counts should be used in constructing the list of potential differential possibilities – Suspect and evaluate accordingly for Pneumocystis pneumonia, TB, and other opportunistic infections when  CD4+ lymphocyte counts < 200/µL  CD4+ lymphocyte counts > 200/µL with unexplained fever, weight loss, or thrush Uncommon Causes of ChronicUncommon Causes of Chronic CoughCough  Cough is the major presenting symptom in many uncommon pulmonary and non-pulmonary disorders. – Diagnosis is often difficult because the clinician does not consider the disorder or because many of the entities don’t exhibit specific or characteristic abnormalities on imaging studies.  Non-respiratory testing may provide the only clues  In patients with chronic cough, uncommon causes should be considered when cough persists after evaluation for common causes and when diagnostic evaluation suggests that an uncommon pulmonary or extrapulmonary condition may be contributing. – Until uncommon causes have been ruled out, the diagnosis of unexplained cough should not be made. – The workup is never done unless a chest CT scan and bronchoscopy have been performed and are normal. – Evaluate for the possibility of drug-induced cough and consider a therapeutic trial of withdrawal. Unexplained CoughUnexplained Cough  There is wide variation among studies of the % of patients with chronic cough in whom no diagnosis can be made (0- 33%). – Based upon the information described in the latter article, a likely diagnosis was actually present and missed in the majority of cases labeled as “unexplained.” – Until a thorough diagnostic and therapeutic approach for the commonest causes of cough have been completed and uncommon causes adequately evaluated, it is likely that many patients will be mis-diagnosed as having “unexplained” cough or psychogenic or habit cough. – Therefore, the diagnosis of unexplained cough is one of exclusion.  Validated diagnostic protocols should be used by all.  The Committee recommends using the term “unexplained” rather than “idiopathic” cough because it is likely that more than 1 unknown causes of chronic cough will be discovered. – The term “idiopathic” implies that one is dealing with 1 disease – The significance of associated organ specific autoimmune diseases and lymphocytic inflammation are unknown
  14. 14. 14 An Empiric IntegrativeAn Empiric Integrative Approach to the Management ofApproach to the Management of CoughCough The following facts regarding chronic cough led to the Committee recommending this approach: – The relative frequency of disorders (singly and in combination) that can cause chronic cough as well as the sensitivity and specificity of many but not all diagnostic tests in predicting the cause of cough are known. – A great deal is also known about specific treatments that work for the various conditions and the expected time frame of response. – It has been suggested by prospective descriptive studies, supported by a theoretical decision analysis, that the initial use of empiric treatment, systematically directed at the common causes of chronic cough, is an important component of a successful approach to the diagnosis and treatment of chronic cough.  Evaluations that are sequential and integrative are important and often needed because more than 1 cause of cough is frequently present.  Marked improvement or resolution of cough is the sine qua non for success.  The Committee also recommends this approach for acute and subacute cough.
  15. 15. 15 Assessing Cough Severity and EfficacyAssessing Cough Severity and Efficacy of Therapy in Clinical Researchof Therapy in Clinical Research  To optimally evaluate the efficacy of cough-modifying agents, subjective and objective methods should be used. – They have potential to measure different things.  With respect to subjective methods: – Cough specific HRQoL instruments should be used primarily because valid and reliable instruments exist – Even though VASs have not been psychometrically tested, they are recommended because they are commonly used, are valid, and likely yield different but complementary results to HRQoL  With respect to objective methods: – Tussigenic challenges can be used before and after intervention to assess the effect of therapy on cough sensitivity.  Will be most helpful in diseases in which cough sensitivity is increased. – It must not be assumed that inflammation and edema of airway structures is specific for any particular disease – Cough counting for 24 hours is recommended with a computerized methodology that is reliable, accurate, noninvasive and portable
  16. 16. 16 Cough Suppressant andCough Suppressant and ProtussiveProtussive PharmcologicPharmcologic TherapyTherapy  Cough suppressant therapy, previously termed non-specific antitussive, incorporates pharmacologic agents with mucolytic and/or inhibitory effects on the cough reflex itself. – The intent of this type of therapy is to reduce the frequency and/or intensity of coughing on a short-term basis. – Unlike specific therapy, these drugs do not resolve the underlying pathophysiology responsible for the coughing.  There is no evidence that this therapy can prevent coughing. – Because of the success of specific therapy, suppressant therapies are necessary only in specific situations.  When the etiology of cough is unknown  When specific therapy requires a period of time before it can work  When specific therapy will be ineffective, as in inoperable lung cancer  Protussive therapy is intended to enhance cough effectiveness to promote clearance of airway secretions. Cough Suppressant andCough Suppressant and ProtussiveProtussive PharmcologicPharmcologic TherapyTherapy  Relatively few drugs are effective for non-specific suppression of cough.  It is recommended that suppressants be guided by specific knowledge of the disorder causing cough – Mucolytic agents are not consistently effective to ameliorate cough in patients with bronchitis. – Zinc preparations are not recommended for cough due to colds – Peripheral (levodropizine, moguisteine) and central antitussive agents (codeine, dextromethorphan) can be useful in patients with chronic bronchitis but have little efficacy in patients with cough due to URI – Opioids are useful in lung cancer  Some protussive agents are effective in increasing cough clearance (amiloride in CF; hypertonic saline in bronchitis) but their long-term effectiveness has not been established. – DNAse is not effective as a protussive in patients with cystic fibrosis NonpharmacologicNonpharmacologic AirwayAirway Clearance TherapyClearance Therapy  A variety of interventions are used to enhance airway clearance to improve lung mechanics and gas exchange, and prevent atelectasis and infection. – Some require the presence of a caregiver (assisted maneuvers) while others can be performed without assistance.  Studies of nonpharmacologic methods are limited by methodological contraints, and most were conducted only in patients with cystic fibrosis. – Chest PT including postural drainage, chest wall percussion and vibration; and forced expiratory technique (“huffing”) ↑ airway clearance but the long-term efficacy of these techniques compared with unassisted cough alone is unknown.  Other devices (positive expiratory pressure and oscillators) appear as effective as Chest PT without assistance of caregiver in ↑ sputum production – Manual or mechanical cough assist devices are recommended in patients with neuromuscular diseases with impaired cough to reduce respiratory complications
  17. 17. 17 NonpharmacologicNonpharmacologic AirwayAirway Clearance TherapyClearance Therapy  While some non-pharmacologic therapies are effective in ↑ sputum production, their long- term efficacy in improving clinically meaningful outcomes (HRQoL, rates of exacerbations, hospitalizations, mortality) is unknown. – The Committee recommends that future investigations measure these outcomes in patients with cystic fibrosis, other populations with bronchiectasis, COPD, and neuromuscular diseases. Guidelines for Evaluating ChronicGuidelines for Evaluating Chronic Cough in PediatricsCough in Pediatrics  Background: – Clinicians specializing in children’s health are well aware of the limitations and possible adversity in extrapolation of data from adults to children. – In the area of cough, there are similarities but also clear clinical and physiological differences between children and adults. – Rigidity in adherence to child-specific data may also be disadvantageous to children given the relative paucity in pediatric research.  Definitions: – Chronic cough = cough > 4 weeks. – Non-specific cough = dry cough in the absence of identifiable respiratory disease of known etiology – Although the cut-off age for pediatric care in the US is 18 years, a lower limit of age 14 is used here for pediatric specific recommendations based upon the limited evidence that adolescents are more like adults in the cough literature. Guidelines for Evaluating ChronicGuidelines for Evaluating Chronic Cough in PediatricsCough in Pediatrics  General Principles: – Children < 15 years old with chronic cough should be managed according to child specific guidelines  The etiological factors and treatments in children are sometimes different from adults – Cough in children should be treated based on etiology; there is no evidence for using medications for symptomatic relief of cough – If medications are used, it is imperative that the children be followed up and medications stopped if there is no effect on the cough within an expected time. – Irrespective of diagnosis, environmental influences and parental expectations should be discussed and managed accordingly. – Because cough often impacts the QoL of both children and parents, parental expectations and fears should be explored. – When pediatric specific cough recommendations are unavailable, adults recommendations should be used with caution.
  18. 18. 18 Anatomy andAnatomy and NeurophysiologyNeurophysiology of the Cough Reflexof the Cough Reflex  There is clear evidence that vagal afferent nerves regulate involuntary coughing  Coughing, like swallowing, belching, urinating, and defecating, is unique because there is higher cortical control of this visceral reflex – Cortical control can manifest as cough inhibition or voluntary cough. The implications of this are several-fold:  Because placebos can have a profound effect on coughing, treatment studies must be placebo controlled  Because cough can be an affective behavior, psychological issues must be considered as a cause or effect of coughing  There is a need to study the roles of consciousness and perception in coughing Global Physiology andGlobal Physiology and PathophysiologyPathophysiology of Coughof Cough  The sequence of events that lead to an effective cough have been classified as inspiratory, compressive, and expiratory.  The inspiratory phase is not critical because an effective cough can be accomplished by inhaling small volumes.  Although glottic closure enhances the expiratory phase of coughing, it is not essential for an effective cough. Therefore, it is recommended that – Tracheostomy need not be performed to improve cough effectiveness in patients with endotracheal tubes.