The Role of Microaspiration in the Pathogenesis of Gastroesophageal Reflux-related Chronic Cough

Abstract

Background/AimsGastroesophageal reflux disease (GERD) is one of the main causes of chronic cough. We evaluated the role of microaspiration in the pathogenesis of reflux-related cough by determining the amount of lipid-laden macrophages (LLMs) in bronchoalveolar lavage (BAL) specimens. MethodsA total of 161 cases of chronic cough were evaluated, and 36 patients (average age 48.2 years) were recruited for this single center prospective study. Patients with a history of smoking, angiotensin converting enzyme inhibitor usage, any abnormality on pulmonary function tests, abnormal chest X-rays, occupational or environmental exposures, or upper airway cough syndrome were excluded. GERD was evaluated by 24-hour esophageal impedance-pH monitoring. BAL specimens for LLM determination were obtained from 34 patients by flexible bronchoscopy. ResultsPatients with pathological intra-esophageal reflux according to multichannel intraluminal impedance and pH monitoring had higher LLM positivity in BAL specimens than patients without pathological reflux (8/14 in reflux positive group vs 1/22 in reflux negative group; P = 0.004). The BAL cell distribution was not different between the 2 groups (P = 0.574 for macrophages, P = 0.348 for lymphocytes, P = 0.873 for neutrophils and P = 0.450 for eosinophils). ConclusionsOur results confirm the role of the microaspiration of refluxate in the pathogenetic mechanism of chronic cough. While bronchoscopy is indicated in patients with chronic cough, in addition to the routine airway evaluation, BAL and LLM detection should be performed. LLM can be used to diagnose aspiration in reflux-related chronic cough. Future studies are needed to evaluate the response to antireflux medications or surgery in patients with LLM positivity.

Acid-Suppressive Drug Use During Pregnancy and the Risk of Childhood Asthma: A Meta-analysis

“…5 Acid-suppressive drugs are considered effective and safe to use during pregnancy to treat gastroesophageal reflux disease (GERD), a common complication that is reported with up to 80% of pregnancies. 6,7 In adults, acidsuppressive drugs may alleviate asthma in patients with GERD, 8 but the drugs are also associated with allergic sensitization. Pali-Schöll and Jensen-Jarolim 9 showed that the impairment of gastric function is a documented risk factor for sensitization against oral proteins and drugs.…”

Combined multichannel intraluminal impedance‐pH monitoring should be used to diagnose reflux‐related otitis media with effusion in children

“…Previously, several studies reported an increased number of eosinophils in several respiratory biological samples, including bronchoalveolar lavage samples, induced sputum and mucosal biopsies in patients with chronic cough and GER . However, not all studies yielded the same results , leading us to the conclusion that inflammation of the airway in patients with GER induced cough is controversial and needs further evaluation.…”

Gastroesophageal reflux disease and chronic cough: A possible mechanism elucidated by ambulatory pH‐impedance‐pressure monitoring

“…One important hypothesis concerning the mechanism of reflux‐induced cough is that proximal reflux and micro‐aspiration of gastric refluxate stimulate coughing by direct irritation of the respiratory tract. Previous studies have found that proximal acid reflux and aspiration of gastric contents (pepsin, bile acid, or lipid‐laden macrophages) can induce CC events. A recent study also found that volume clearance time and reflux burden play key roles in inducing coughing .…”