Commentary

Cough and gastro-oesophageal reflux

To critically review and summarize the literature on cough and gastroesophageal reflux disease (GERD), and to make evidence-based recommendations regarding the diagnosis and treatment of chronic cough due to GERD.

Ovid MEDLINE literature review (through March 2004) for all studies published in the English language and selected articles published in other languages such as French since 1963 using the medical subject heading terms “cough,” “gastroesophageal reflux,” and “gastroesophageal reflux disease.”

GERD, singly or in combination with other conditions, is one of the most common causes of chronic cough. In patients with normal chest radiographic findings, 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-h esophageal pH monitoring is the most sensitive and specific test in linking GERD and cough in a cause-effect relationship, it has its limitations. In addition, there is no general agreement on how to best interpret the test, and it cannot detect non-acid reflux events. Therefore, when patients fit the clinical profile that has a high likelihood of predicting that GERD is the cause of cough, antireflux medical therapy should be empirically instituted. While some patients improve with minimal medical therapy, others require more intensive regimens. When empiric treatment fails, it cannot be assumed that GERD has been ruled out as a cause of chronic cough. Rather, an objective investigation for GERD is then recommended because the empiric therapy may not have been intensive enough or medical therapy may have failed. Surgery may be efficacious when intensive medical therapy has failed in selected patients who have undergone an extensive objective GERD evaluation.

Accurately diagnosing and successfully treating chronic cough due to GERD can be a major challenge.

While medical therapy may fail to improve cough due to gastroesophageal reflux disease (GERD), it is not known if inadequate esophageal acid suppression is responsible.

In a prospective, before-and-after interventional trial, we assessed the effects of antireflux surgery in eight patients whose chronic coughs were due to GERD resistant to intensive medical therapy. All patients met a profile predicting that cough was likely due to GERD and had an initial positive 24-h esophageal pH monitoring study, and then underwent serial 24-h esophageal pH monitoring on gradually intensified medical therapy until the percentage of time that esophageal pH was < 4 was zero and there were no acid reflux events > 4 min. The effects of medical and surgical therapy on cough were assessed clinically by a visual analog scale (VAS) and the Adverse Cough Outcome Survey (ACOS).

Before surgery (median, 23.7 days), patients still complained of cough, VAS score was 73.1 ± 6.1, and ACOS score was 15.0 ± 1.1. After surgery (median, 41.2 days and 1 year), cough improved in all, VAS score decreased to 19.1 ± 8.3 and 22.6 ± 8.1 (p = 0.001), respectively, and ACOS score decreased to 2.0 ± 1.3 and 3.6 ± 2.3, respectively (p = 0.002).

Antireflux surgery can improve chronic cough due to GERD resistant to intensive medical therapy. There is a clinical profile that can predict when GERD is the likely cause of cough. GERD cannot be excluded on clinical grounds as the potential cause of cough. The term acid reflux disease, when applied to chronic cough due to GERD, can be a misnomer.

In addition to heartburn and regurgitation, cough is a frequent nonspecific complaint of patients with gastroesophageal reflux disease. The incidence of alternative etiologies for patients with chronic cough who are undergoing antireflux surgery is not known. To determine this, and the response of chronic cough to fundoplication, we performed a retrospective review of 129 patients with proven gastroesophageal reflux referred for surgical therapy. Chronic cough was present in 37 (29%) preoperatively. No differences were found in age, sex, or preoperative manometric findings between those with and without chronic cough. Patients with cough had a higher number of lower esophageal reflux events on preoperative 24-hour pH testing, and were more likely to have persistent dysphagia after surgery. Fifty-nine percent of patients with cough had an alternative etiology for cough, compared to 36% of those without cough. Of the common alternative etiologies, only a history of postnasal drip occurred more frequently in those with cough. Complete resolution of cough occurred in 24 patients (64%), with another 10 (27%) reporting significant improvement. The average cough score improved significantly regardless of which coexisting etiology the patients may have had. Additionally, heartburn and regurgitation were improved in 94% of all patients. (J Gastrointest Surg 2002;6:17–21.)

Patients with cough may be conveniently divided into those with acute, usually viral, illness and those with chronic cough. Acute cough represents the largest single cause of consultation in primary care, whereas chronic cough is one of the commonest presentations in respiratory medicine. The world-wide market in cough treatments is several billion dollars. In both syndromes, cough sensitivity is upregulated, but the inflammation giving rise to cough is localised to the larynx and large airways in acute cough. Whilst this is also true of cough-predominant asthma, the origin of cough in chronic disease may also lie in the oesophagus, nose or sinuses leading to errors in diagnosis and treatment.