Evidence-Based Approach for Diagnosis, Treatment of Chronic Cough

April 27, 2007 — An evidence-based review published in the April issue of the Annals of Allergy, Asthma & Immunology provides information on various diagnoses and treatment of chronic cough in adults and children.

"Chronic cough (lasting longer than 8 weeks in adults and 4 weeks in children) is a common (10% to 20% of adults) and debilitating ailment," write Matthew A. Rank, MD, from Mayo Clinic in Rochester, Minnesota, and colleagues. "Cough has an important physiologic role in the human body's defense system, because it results in clearing of excess secretions and foreign bodies from the airway. However, in some patients cough may be excessive and unnecessary and may lead to a general deterioration in their quality of life."

Three major organizations have published guidelines for the evaluation and treatment of chronic cough: the American College of Chest Physicians (ACCP), the British Thoracic Society (BTS), and the European Respiratory Society. This review covers the key points of these guidelines, the underlying evidence, emphasizing the 3 leading causes of chronic cough in adults (upper airway cough syndrome [UACS; also known as postnasal drip syndrome], asthma, and gastroesophageal reflux disease [GERD]), and important aspects of diagnosing and treating chronic cough in children.

The authors searched MEDLINE, PubMed, EMBASE, and CINAHL for "cough," "asthma," "gastroesophageal reflux," "sinusitis," "rhinitis (allergic, seasonal)," "postnasal drip," "vocal cord dysfunction," "lung disease (interstitial)," "bronchiectasis," and "bronchoscopy." They selected studies based on their relevance to diagnosis and treatment of chronic cough. Very few randomized prospective studies were identified, so the authors selected nonrandomized and retrospective studies after considering their strengths and limitations.

"There are several prospective, noncontrolled trials for adults with chronic cough that found a high percentage of cough resolution when using an approach that focused on the diagnosis and treatment of the most common causes: asthma, gastroesophageal reflux disease, and upper airway cough syndrome," the authors write. "Preliminary studies in children support an approach that distinguishes between a wet and dry cough, as well as an in-depth investigation of any specific symptoms that point to an underlying chronic illness. Allergists, as experts in treating upper airway and lower airway disorders, are uniquely poised to diagnose and treat chronic cough."

The authors recommend a management approach using an anatomic, diagnostic protocol that emphasizes the sites of the vagus afferent nerve endings. For most patients, this approach will result in successful resolution of the cough.

In adult patients with no obvious cause for cough, the 3 most common causes are UACS, asthma, and GERD. These conditions mandate careful workup and treatment.

For adults with normal chest x-ray findings and a history of no smoking, the authors recommend the following testing for and treatment of various causes of chronic cough:

UACS: Treat the specific cause if found; otherwise, use empiric treatment with intranasal steroid or first-generation antihistamine or decongestant.

GERD: Treat empirically with medical antireflux therapy. If there is no improvement, consider additional testing with pH probe test, esophagram, or manometry.

Asthma: Test with barometry plus bronchoprovocation if necessary. Otherwise, empiric treatment may include inhaled corticosteroids and leukotriene modifiers or systemic steroids.

Nonasthmatic eosinophilic bronchitis: Test for sputum eosinophils if available; treat with inhaled corticosteroids.

Angiotensin-converting enzyme inhibitor cough: Discontinue use of angiotensin-converting enzyme inhibitors and monitor for improvement for 3 months.

Occupational cough: Eliminate, reduce, or modify exposure to the triggering factors.

Suppurative airway disease: Diagnose with bronchoscopy and treat with long-term antibiotics.

Lung tumors: If suspicion remains even though chest x-ray and chest computed tomography findings are normal, proceed with bronchoscopy.

Aspiration: Perform a swallow evaluation and treat based on the findings.

Tic cough: Refer the patient for a psychiatry consult.

Arnold nerve: Remove the irritant from the tympanic membrane.

Unexplained cough: Treat empirically with antitussive medications.
In children with chronic cough, specific findings may be clues assisting in making a specific diagnosis. Wheezing may point to asthma or tracheomalacia; crackles, to parenchymal disease; purulent cough, to bronchiectasis or cystic fibrosis; digital clubbing, to suppurative lung disease; developmental delay, to aspiration; and failure to thrive may indicate serious systemic illness.

"Chronic cough is one of the leading causes of consultation with a physician [and] a concerning and frustrating symptom for patients, many of whom have already experienced failed previous intervention," the authors conclude. "Chronic cough in children should be approached differently than in adults. When one considers the leading cause(s) of chronic cough, it is clear that allergists should be pivotal in the evaluation and treatment of this condition."

Astra-Zeneca supported this review, in part, as an educational grant. Two authors have disclosed that in the past 12 months they were on the consultant/speakers' bureaus for Merck, GSK, Astra-Zeneca, Schering, Pfizer, UCB, Abbott, Wyeth, Greer, and Aventis.

Ann Allergy Asthma Immunol. 2007;98:305-313.

Source: http://www.medscape.com/viewarticle/555784?src=mp