COUGH

COUGH

  1. 1
    Current diagnosis
    • Acute Cough
      • Noninfectious
      • Chronic obstructive pulmonary disease exacerbation
      • Asthma exacerbation
      • Congestive heart failure exacerbation
      • Pulmonary embolism
    • Infectious
      • Viral rhinosinusitis (the common cold)
      • Acute bacterial sinusitis
      • Acute bronchitis (chest cold)
      • Pneumonia
      • Pertussis (whooping cough)
      • Bronchiolitis (infants)
    • Chronic cough
      • First, evaluate/rule out
        • Tobacco smoking and risk for lung cancer
        • Angiotensin-converting enzyme (ACE) inhibitor associated cough
      • Next, evaluate for the three most common etiologies
        • Chronic upper airway cough syndrome
        • Cough variant asthma/nonasthmatic eosinophilic bronchitis
        • Gastroesophageal reflux disease
      • Last, consider other causes and more advanced testing (bronchoscopy, high-resolution computed tomography [CT] scanning, referral) and consider earlier if history, physical, or chest x-ray suggests an alternative diagnosis
        • Oral pharyngeal dysphagia
        • Lung tumors
        • Interstitial pulmonary diseases
        • Bronchiectasis
        • Occupational and environmental exposures
        • Sarcoidosis
        • Tuberculosis
        • Somatic cough syndrome
        • Tic cough
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  2. 2
    Current therapy
    • Acute cough due to viral rhinosinusitis
      • Dextromethorphan (Delsym) 30 mg PO every 6 to 8 hours × 1 week
      • Diphenhydramine (Benadryl) 25 mg PO every 4 hours × 1 week
      • Nasal saline irrigation twice daily × 1 week
    • Acute or subacute cough caused by Bordetella pertussis
      • Azithromycin (Z-Pak) 500 mg PO on day 1 followed by 250 mg PO daily on days 2 to 5
    • Treatment of unexplained chronic cough
      • Multimodality speech pathology therapy
      • Gabapentin (Neurontin) 300 mg PO daily, can be titrated up to a maximum daily dose of 1800 mg a day in two divided doses (off label use)
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  3. 3
    Acute Cough

    Acute cough is a cough that lasts fewer than 3 weeks. It is a common presenting complaint in the primary care physician’s office and also in the emergency room. The key goal is to differentiate between those patients whose cough has a benign cause and those who may be at risk for more serious illness. Infectious causes of cough are most common, but noninfectious causes should also be considered.

    Exacerbations of preexisting pulmonary conditions such as asthma and chronic obstructive pulmonary disease (COPD) can be associated with cough, therefore a thorough medical history should be obtained. Cough can also be associated with decompensated heart failure; in fact, cough is present in 70% of congestive heart failure (CHF) exacerbations. Also, 30% to 40% of patients with acute pulmonary embolism (PE) have a new cough at presentation of symptoms, and the classic signs and symptoms of chest pain, dyspnea, and hypoxia may not always accompany the cough.

    Upper respiratory tract infections are a common cause of benign acute cough. The common cold, also known as viral rhinosinusitis, is probably the most common cause of acute cough. The lung exam is normal. If fever is present it is low grade and is only present on the first or second day of illness. Most symptoms begin to resolve by 7 to 10 days, but cigarette smokers may be ill for twice as long.

    Symptomatic treatment is the mainstay of therapy. First generation antihistamines combined with a decongestant and naproxen have been proven to reduce the length of cough. Second generation antihistamines are not effective in the treatment of cough associated with viral rhinosinusitis; it is likely that first generation antihistamines are effective because of their anticholinergic properties. Other treatments that may be helpful include nasal saline irrigation, nasal glucocorticoids, and nasal decongestants. It is necessary to distinguish viral rhinosinusitis from acute bacterial rhinosinusitis, which may also be associated with cough. Less than 2% of all rhinosinusitis has a bacterial cause. Acute bacterial rhinosinusitis should not be diagnosed in the first week of symptoms unless the patient displays severe symptoms such as high fever. Sinus imaging studies are unlikely to be helpful, as both viral and bacterial sinusitis will have radiologic evidence of inflammation.

    It is also necessary to distinguish an acute cough caused by an upper respiratory tract infection and that caused by a lower respiratory tract infection. Furthermore, it is necessary to distinguish between acute bronchitis, which almost always has a viral cause, versus pneumonia, which has a bacterial cause. Both illnesses often have a presenting symptom of cough, which may be productive. If there is any derangement in vital signs or evidence of pulmonary consolidation on the lung exam, a chest x-ray should be performed. Infectious Diseases Society of America (IDSA) guidelines require the presence of consolidation on chest x-ray to diagnose pneumonia.

    Influenza should also be considered for those patients who have fever and cough during flu season. An elevated procalcitonin level may help guide the physician in his or her decision to prescribe antibiotics. Beta agonists should not be routinely used to alleviate cough in acute viral bronchitis, but may be helpful for the alleviation of wheezing and are more likely to benefit patients with airflow obstruction at baseline.

    In pediatric patients, bronchiolitis should be considered as a cause of cough and fever. It is the most common cause of hospitalization in those less than 1 year old. The most recent guidelines recommend abstaining from lab testing (including viral swabs), radiographic imaging, and treatment with beta agonists, epinephrine, or glucocorticoids as these interventions do not change the course of illness. Exclusive breastfeeding for the first 6 months of infancy can decrease the morbidity of respiratory infections. Bordetella pertussis can cause severe illness with cough and apnea in infants. However, adults have subtle symptoms and lack the classic “whooping cough” and posttussive emesis seen in children. The physician should have suspicion for pertussis in patients who have a cough lasting longer than 2 weeks and paroxysms of coughing; the cough can last up to 2 months. The diagnosis can be confirmed with polymerase chain reaction (PCR). Antibiotics do not alter the course of illness but reduce the spread of infection; azithromycin should be given for 3 to 5 days.

    Vaccination rates remain low. Pregnant women should be vaccinated with each pregnancy and other adults should replace 1 dose of Td at the earliest convenience.

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  4. 4
    Chronic Cough

    A chronic cough is a cough lasting more than 8 weeks. Patients may have a presenting symptom of a cough that has been present for more than 3 but fewer than 8 weeks; this is considered a subacute cough. In this case, the physician should illicit a history of respiratory infection; the patient is likely suffering from a postinfectious cough, which is related to inflammation of the airway epithelium, mucus hypersecretion, and/or increased cough reflex sensitivity. Inhaled corticosteroids may provide some benefit. If there is no history of recent infection, then the cough should be managed as a chronic cough. Chest x-ray can be considered during this time frame, but if no red flags are present (fever, unintended weight loss, night sweats, dysphagia, odynophagia, hemoptysis) the physician and patient together can decide to wait on radiography.

    Upper Airway Cough Syndrome

    Upper airway cough syndrome (UACS), previously called postnasal drip syndrome, is likely caused by activation of cough receptors in the hypopharynx or larynx and increased sensitivity of these receptors. It is likely the most common cause of chronic cough. UACS is almost always associated with rhinosinusitis, which can be caused by a number of factors (allergic rhinitis, postinfectious rhinitis, perennial nonallergic rhinitis, rhinitis resulting from chemical irritants, rhinitis medicamentosa, pregnancy-associated rhinitis, bacterial sinusitis, allergic fungal sinusitis, etc.). The patient may complain of frequently needing to clear the throat or a sensation of “dripping” in the back of the throat; however, absence of these symptoms does not rule out UACS, nor does a history of wheezing. Physical exam may reveal mucus in the posterior oropharynx and cobblestoning of the mucosa. If the cause of rhinitis is obvious, it should be specifically treated.

    Otherwise, a trial of a first generation antihistamine should be started; improvement should be seen in 2 weeks. If the side effects of this therapy are intolerable, a nasal antihistamine, nasal anticholinergic, or nasal corticosteroid can be used. If the diagnosis of UACS is highly suspected but the patient does not respond to empiric therapy, sinus CT imaging may be necessary to guide diagnosis and treatment.

    Cough Variant Asthma and Nonasthmatic Eosinophilic Bronchitis

    Cough variant asthma and nonasthmatic eosinophilic bronchitis (NAEB) both primarily present with a cough, and the patient may have few other symptoms. Patients with cough variant asthma will have abnormal spirometry, whereas those with NAEB will not. When spirometry is performed, bronchoprovocation testing with methacholine should be performed as it increases the negative predicative value of the test. If spirometry is negative, the sputum should be evaluated for eosinophils, which are present in both diseases. Both diseases are treated as asthma; an inhaled corticosteroid should be started and long-acting beta agonists and leukotriene receptor antagonists can be considered as adjunctive therapy. A positive response should be expected within 2 weeks.

    Gastroesophageal Reflux Disease

    Gastroesophageal reflux disease (GERD) is common, but not all patients with GERD have an associated cough; therefore, the presence of GERD does not ensure that it is the source of the patient’s cough.

    However, those patients whose cough is clearly not caused by UACS, cough variant asthma or NAEB are very likely to have a GERD- induced cough. Cough can be caused by acidic and nonacidic reflux, so a proton pump inhibitor (PPI) may not always be of benefit. A pH probe can be performed in cases when it is unclear whether reflux is occurring. All patients should utilize lifestyle changes to attenuate reflux, such as smoking cessation, avoidance of alcohol and acidic foods, weight loss, and treatment of sleep apnea. It may take 3 to 6 months of treatment to see improvement in cough. If the patient does not improve and GERD is highly suspected, referral to a surgeon may be necessary for fundoplication.

    Other Causes of Chronic Cough

    In those patients who still suffer from chronic cough and the above causes have been ruled out, further investigation should be sought.

    Referral to a pulmonologist may be necessary, in addition to high- resolution CT scanning and bronchoscopy. Causative factors may include oral pharyngeal dysphagia, lung tumors, interstitial pulmonary diseases, bronchiectasis, occupational and environmental exposures, sarcoidosis, and tuberculosis. Somatic cough syndrome (previously referred to as psychogenic cough) and tic cough (previously referred to as habit cough) may be considered in some patients; hypnosis, suggestion therapy, and/or counseling may be beneficial. In patients who remain symptomatic, regardless of known or unknown causes, the diagnosis of “difficult to treat” cough is made. Options do remain for these patients, including speech language pathology intervention, empiric gabapentin, and/or referral to a cough clinic.

    Chronic cough must be approached in a systematic manner, which is more likely to identify the causative agent of the cough and provide alleviation of symptoms. All of the common causes of chronic cough (see later) must be considered, as the associated symptoms and the patient’s description of the cough do not alter the diagnostic algorithm. Failure to respond to empiric treatment does not necessarily rule out a diagnosis, as the patient may have two diagnoses.

    First, it must be determined if the patient smokes. If so, the differential diagnosis is altered. The physician must determine if the smoke is a simple smoker’s cough, chronic bronchitis, or possibly lung cancer; cough is the most common presenting symptom of lung cancer. Smokers are less likely to seek help for a cough and may not see a physician until a more serious problem has advanced. It is possible for a cough to worsen initially after smoking cessation, but a cough persisting more than 1 month after cessation should be investigated. Any change in a smoker’s cough, a new cough, and cough with hemoptysis should be investigated. Physicians should consider low dose CT scanning as screening for lung cancer in qualifying smokers. The second factor to rule out in all chronic cough cases is cough induced by an angiotensin-converting enzyme (ACE) inhibitor. All patients with chronic cough should stop taking an ACE inhibitor. The medication is more likely to cause a cough if it was started in the prior year, and the cough should resolve within 1 month after cessation of the ACE inhibitor. The next step to determining the cause of a chronic cough is to rule out the three most common causes of cough. Last, all patients with a cough lasting more than 8 weeks should be evaluated with chest radiography to identify any obvious causative factors.

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KNOWLEDGE BASE
About Genomic Medicine UK

Genomic Medicine UK is the home of comprehensive genomic testing in London. Our consultant medical doctors work tirelessly to provide the highest standards of medical laboratory testing for personalised medical treatments, genomic risk assessments for common diseases and genomic risk assessment for cancers at an affordable cost for everybody. We use state-of-the-art modern technologies of next-generation sequencing and DNA chip microarray to provide all of our patients and partner doctors with a reliable, evidence-based, thorough and valuable medical service.

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