Chronic Cough

Majid Ali, M.D.

Chronic Cough – Think Mold Allergy, Please!


 

 

Clinical Pearls

1.  Chronic cough is generally defined as cough that persists for more than 8 weeks.

2. It is common and often disabling.

3. As for its cause, I think of the big three:

A. Mold allergy

B. GERD-gastritis complex

C. COPD, Asthma, Bronchiectasis, chronic bronchitis


 

Treatment for Chronic Cough

First, rule out lung tumors in adults.

Second, think of the colon and restore colon flora.

Third, restore stomach flora.its the

Fourth, restore immunity with nondrug therapies.


 

The New England Journal recommends the following (which is not my choice):

“Limited data from clinical trials support a benefit of low-dose morphine, gabapentin or pregabalin, and speech therapy for patients with cough persisting after other investigations and empirical treatments.”  See below for the Journal text.

 

 


  • (cough >8 weeks in duration) is common and can be disabling.

  • Chronic cough is a feature of many respiratory diseases, and common triggers (asthma, esophageal reflux, and postnasal drip) should be routinely ruled out by testing or by treatment trials. Investigation and treatment algorithms are based largely on consensus opinion, and more data are needed from randomized trials.

  • Limited data from clinical trials support a benefit of low-dose morphine, gabapentin or pregabalin, and speech therapy for patients with cough persisting after other investigations and empirical treatments.

  • Newer evidence suggests that cough reflex hyperresponsiveness underlies chronic cough, although more research is needed into the mechanisms and associated potential treatments.

Chronic cough is a feature of many common respiratory diseases (e.g., chronic obstructive pulmonary disease, asthma, and bronchiectasis) and of some common nonrespiratory conditions (e.g., gastroesophageal reflux and rhinosinusitis),


Smith JA, Woodcock A. Chronic Cough.N Engl J Med 2016; 375:1544-1551

October 26, 2016

 

 

This Journal feature begins with a case vignette highlighting a common clinical problem. Evidence supporting various strategies is then presented, followed by a review of formal guidelines, when they exist. The article ends with the authors’ clinical recommendations.

A 63-year-old woman presents with a 1-year history of a chronic dry cough, associated with a sensation of “irritation” in the throat. Prolonged bouts of coughing are associated with stress urinary incontinence and occasionally end with retching and vomiting. The cough is triggered by changes in temperature, strong smells (e.g., the smell of cleaning products), laughing, and prolonged talking. She has no notable medical history, reports being otherwise well, and does not smoke. She has been prescribed a bronchodilator and inhaled and nasal glucocorticoids, but has had no benefit from any of these. The results of a physical examination, chest radiography, and spirometry are normal. How would you further evaluate and manage this condition?

THE CLINICAL PROBLEM

Cough is the most common symptom for which patients seek medical attention.1 Estimates of the prevalence of cough vary, but as much as 12% of the general population report chronic coughing, defined as a cough lasting for more than 8 weeks.2 Chronic cough is more common among women than among men, most commonly occurs in the fifth and sixth decades of life, and can persist for years, with substantial physical, social, and psychological effects.3,4 The disabling effects of chronic cough are understandable, given that patients with the condition cough hundreds or even thousands of times per day; this is similar to the frequency of coughing that occurs in acute viral cough, but chronic cough can persist for months or years.5,6 Most patients describe the cough as dry or productive of minimal amounts of sputum; excessive sputum suggests bronchiectasis or sinus disease.

KEY CLINICAL POINTS

Chronic Cough

  • Chronic cough (cough >8 weeks in duration) is common and can be disabling.

  • Chronic cough is a feature of many respiratory diseases, and common triggers (asthma, esophageal reflux, and postnasal drip) should be routinely ruled out by testing or by treatment trials. Investigation and treatment algorithms are based largely on consensus opinion, and more data are needed from randomized trials.

  • Limited data from clinical trials support a benefit of low-dose morphine, gabapentin or pregabalin, and speech therapy for patients with cough persisting after other investigations and empirical treatments.

  • Newer evidence suggests that cough reflex hyperresponsiveness underlies chronic cough, although more research is needed into the mechanisms and associated potential treatments.

Chronic cough is a feature of many common respiratory diseases (e.g., chronic obstructive pulmonary disease, asthma, and bronchiectasis) and of some common nonrespiratory conditions (e.g., gastroesophageal reflux and rhinosinusitis), and it may be the presenting symptom of patients with some rarer conditions (e.g., idiopathic pulmonary fibrosis and eosinophilic bronchitis). Cough is also listed as a side effect of many drug treatments but is most commonly associated with the use of angiotensin-converting–enzyme (ACE) inhibitors; cough occurs in approximately 20% of patients treated with ACE inhibitors.7 Patients with chronic cough present to health care providers in a wide range of specialties, and if successful resolution is not rapidly achieved, these patients can pose diagnostic and management challenges to many clinical services and may see numerous doctors.8The natural history of chronic cough among patients in primary care settings has not been well studied. However, in a series of patients who had chronic cough that was unexplained after evaluation at a specialty clinic and who were reevaluated more than 7 years later, cough had spontaneously resolved in 14% and had decreased in 26% of the patients.9

STRATEGIES AND EVIDENCE

Professional guidelines describe systematic approaches to the evaluation and management of chronic cough10-13; these guidelines are based largely on consensus opinion and observational data from the medical literature. Although there are national differences in the delivery of health care, the availability of diagnostic tests, and management strategies, the approach can be broadly simplified into four main steps (Figure 1FIGURE 1Steps for the Evaluation and Treatment of Patients with Chronic Cough.).

Step 1: Identification and Treatment of Obvious Causes

Initial evaluation of the patient, including a medical history, clinical examination, chest radiography, and spirometry, can identify or rule out a wide range of conditions that may underlie chronic cough, and the initial management of the condition should be guided by any positive findings. The history and physical examination should address medications such as ACE inhibitors, smoking or occupational exposures, and any symptoms or signs that suggest a serious underlying disease (e.g., weight loss or hemoptysis, either of which may raise concern regarding lung cancer). Asthma is often suggested by a history of wheezing; however, in some patients with asthma, wheezing is absent or trivial, a condition called “cough-variant asthma.”14 Spirometry in these cases may reveal an obstructed pattern that reverses with a bronchodilator. If there is any possibility of foreign-body inhalation, urgent investigation is warranted.

Step 2: Focused Testing for and Treatment of Asthma, Gastroesophageal Reflux, and Rhinosinusitis

In the context of normal results of chest radiography and spirometry, the most common conditions associated with chronic cough are asthma, gastroesophageal reflux disease, and rhinosinusitis,15although the prevalence of each of these varies substantially among cough clinics.16

Although most cases of asthma are associated with abnormalities on routine spirometry, methacholine challenge to assess for bronchial hyperreactivity is indicated for patients who have normal results and no other obvious cause of cough; levels of exhaled nitric oxide may also be elevated.17 Although data from randomized trials to guide the management of cough-variant asthma are lacking, clinical experience suggests that this condition usually responds to treatment with inhaled glucocorticoids. Inhaled medications trigger the cough in some patients, which inevitably reduces the delivery of the treatment to the airways. In some patients, the cough responds well to a change of inhaler device (e.g., the use of a spacer device); in other patients, treatment with oral glucocorticoids for 1 to 2 weeks may be helpful.

The relationship between cough and esophageal reflux is complex but is becoming clearer.18Guidelines suggest a trial of treatment with acid-suppression therapy — for example, twice-daily treatment with proton-pump inhibitors (PPIs) for up to 3 months — in patients with chronic cough.11,12,19 However, many patients with cough do not have symptomatic gastroesophageal reflux disease, and most randomized, controlled trials of reflux treatment for cough have not shown a significant improvement in association with this type of treatment.20,21 There is likewise no good evidence that antireflux surgery (laparoscopic fundoplication) is an effective treatment for chronic cough, and its use should be limited to patients who meet the criteria for the surgery on the basis of symptoms of gastroesophageal reflux disease and assessments confirming that this condition is present.

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