دكتر محمد امامي فوق تخصص ريه عضو هيات علمي دانشگاه رييس بخش ريه الزهرا

Acute cough exists for less than three weeks -

 acute respiratory tract infection  an acute exacerbation of underlying chronic pulmonary disease  pneumonia  pulmonary embolism

subacute (three to eight weeks) or chronic (more than eight weeks).

upper airway cough syndrome asthma gastroesophageal reflux

Bronchiectasis Angiotensin-converting enzyme inhibitors Nonasthmatic eosinophilic bronchitis Bronchogenic carcinoma Interstitial lung disease Occult pulmonary infection Occult heart failure Occult aspiration Tracheobronchial foreign body or mass (other than bronchogenic carcinoma) Occupational asthma Nasal polyps Disorders of the external auditory canals, pharynx, larynx, diaphragm, pleura pericardium, esophagus, stomach, or thyroid Psychogenic

 The most common cause  Symptoms of postnasal drip include frequent nasal discharge, a sensation of liquid dripping into the back of the throat, and frequent throat clearing.  no definitive criteria for its diagnosis  mucosal thickening is a relatively nonspecific finding

 Asthma is the second leading cause of persistent cough in adults  the most common cause in children  Cough due to asthma is commonly accompanied by episodic wheezing and dyspnea.

 Often nocturnal  Cough variant asthma can progress to include wheezing and dyspnea.

 A diagnosis of asthma is suggested when the patient is atopic or has a family history of asthma.  Asthma-related cough may be seasonal  may follow an upper respiratory tract infection  may worsen upon exposure to cold, dry air, or certain fumes or fragrances.  A cough accompanied by wheezing or dyspnea, or one that occurs following initiation of beta-blocker therapy also suggests asthma.

 the best way to confirm asthma as a cause of cough is to demonstrate improvement in the cough with appropriate therapy for asthma (eg, one week of inhaled beta-agonist therapy)

 Patients with this disorder demonstrate atopic tendencies  with elevated sputum eosinophils and active airway inflammation  absence of airway hyperresponsiveness  Airway eosinophils and basement membrane thickening are present in both asthma and eosinophilic bronchitis, but mast cell infiltration is noted only in asthmatics, which may explain the differences in airway reactivity.

 The natural history of nonasthmatic eosinophilic bronchitis is variable.  13 percent developed asthma.  Patients with recurrent episodes of symptomatic eosinophilic bronchitis appear to be at increased risk of asthma and chronic airway obstruction.

 second or third most common cause of persistent cough.  Many patients complain of symptoms of gastroesophageal reflux.  these symptoms are absent in more than 40 percent of patients.

 Stimulation of receptors in the upper respiratory tract (eg, in the larynx).  Aspiration of gastric contents, leading to stimulation of receptors in the lower respiratory tract.  An esophageal-tracheobronchial cough reflex induced by reflux of acid into the distal esophagus.

 Prolonged (24 hour) esophageal pH monitoring, ideally performed with event markers to allow correlation of cough with esophageal pH, is generally considered the optimal diagnostic study, with a sensitivity exceeding 90 percent.

 No specific pattern of the cough  Long standing  May be productive

 Most patients are relatively unaware of LPR with only 35 percent reporting heartburn.  Typical LPR symptoms include dysphonia/hoarseness, chronic cough, mild dysphagia and nonproductive throat clearing.

 Mycoplasma pneumoniae  Chlamydophila pneumoniae  Bordetella pertussis

 Chronic bronchitis should be considered in a patient who produces sputum on most days over at least 3 consecutive months, particularly during the winter months, over at least 2 consecutive years. In a smoker, the presence of chronic bronchitis may be predictive of progressive irreversible airflow obstruction.

o Cough is a major symptom of bronchiectasis

 nonproductive cough  occurring in up to 15 percent of patients treated with these agents  It may appear within a few hours of taking the drug, but may also become apparent only after weeks or even months.  The cough disappears within days or weeks following withdrawal of drug.  It is a more common complication in women than in men.  It does not occur more frequently in asthmatics than in non-asthmatics.

 Although the pathogenesis of the cough is not known with certainty, it has commonly been hypothesized that accumulation of bradykinin, which is normally degraded in part by ACE, may stimulate afferent C-fibers in the airway.

 lung cancer is the etiology in less than 2 percent of the cases of chronic cough  neoplasms originating in the large central airways, where cough receptors are common.

 A new cough or a recent change in chronic "smoker's cough"  A cough that persists more than one month following smoking cessation  Hemoptysis that does not occur in the setting of an airway infection.

 arteriovenous malformations  retrotracheal masses  tracheobronchomalacia  Tracheal diverticuli  Irritation of the external auditory canal by impacted foreign bodies or cerumen  habit or psychogenic

 In the management of a patient with cough, the first step is to identify the cause of the cough and then treat the cause.

 cough is very severe  if treatment of the cause does not lead to sufficient cough suppression  or if treatment of the cause is not possible or successful.

 Opiates including morphine, diamorphine, and codeine are the most effective antitussive agents

 Morphine and diamorphine are reserved for the control of cough and pain of terminal bronchial cancer patients, but codeine, dihydrocodeine, and pholcodeine can be tried in other cases of chronic cough.

 methylether of morphine  centrally acting antitussive  Codeine is probably the most commonly prescribed antitussive  It should be used cautiously in patients with reduced hepatic function, but it can be used without dose modification in patients with renal failure.

 Dextromethorphan is probably the most common non-opioid agent used for cough.  a synthetic derivative of morphine with no analgesic or sedative properties.  It is as effective as codeine in suppressing acute and chronic cough when given orally.  Side effects are few at the usual dose, but at higher doses, dizziness, nausea, vomiting, and headaches may occur.  It should be avoided in patients with hepatic insufficiency as it undergoes metabolic degradation in the liver.

 The American Academy of Pediatrics has highlighted the potential adverse effects and overdosage associated with antitussive preparations containing dextromethorphan in children,where dextromethorphan has been shown to be ineffective in cough due to upper respiratory tract infections.

 Dextromethorphan should be used with caution also in patients on monoamine oxidase inhibitors as cases of central nervous depression and death have occurred.

 a peripherally acting antitussive agent that presumably acts by anesthetizing stretch receptors in the lungs and pleura.  possible central effect.

 Blocking the efferent limb of the cough reflex  Decreasing stimulation of cough receptors by alteration of mucociliary factors.

 intranasal glucocorticoids are the most effective therapy for symptoms of allergic rhinitis.  oral and nasal antihistamines  oral decongestants  oral leukotriene receptor antagonists

 First generation antihistamines are preferred over second generation ones (eg, cetirizine, fexofenadine, loratadine) due to the stronger anticholinergic effect, but concern over the sedating effects may limit their use.  Lack of improvement in cough after one to two weeks of empiric therapy for UACS is evidence that UACS is not the cause of the cough.

 inhaled glucocorticoids (GC)  inhaled bronchodilators  The leukotriene receptor antagonists (LTRA)  a short (one to two week) course of oral prednisone

 inhaled glucocorticoid  oral glucocorticoids are needed for refractory symptoms

 lifestyle modifications  acid suppression medication

 Acid suppression medications are a key component to the treatment of cough due to GERD. However, regimens proven effective in the management of GERD may not necessarily be the optimum regimen for cough due to GERD.  A 3 months, treatment at the highest recommended dose of a proton pump inhibitor is usually advocated. Not all patients respond and, in some, the response is only partial. One of the reasons for this failure may be the effect of the nonacid refluxate.

 theophylline  inhaled sodium cromoglycate  a thromboxane antagonist (picotamide)  the treatment of choice is withdrawal of the ACE inhibitor. The cough will typically resolve within one to four weeks after stopping the ACE inhibitor, but occasionally will last up to three months.

 Cough may also be a sign of disease in or outside the airways and lungs and a useful indicator for both patient and physician for initiating diagnosis and treatment of disease processes.  Impairment or absence of coughing can be harmful or even fatal in disease  When cough itself is persistent and excessive, it can be harmful and deleterious and may need to be suppressed directly.

 The most sensitive sites for initiating cough are the larynx and the tracheobronchial tree.  In the management of a patient with cough, the first step is to identify the cause of the cough and then treat the cause.  Patients on ACE inhibitor therapy should discontinue such therapy, with replacement by other appropriate treatments.  Postnasal drip, asthma, and GER are the three most common conditions associated with a chronic cough, and a diagnostic approach to exclude these conditions first is sensible.