Heartburn is the first thing most people think about when acid reflux is mentioned. But the effects of chronic acid reflux, also known as gastroesophageal reflux disease, or GERD, can extend beyond the digestive tract. GERD may cause, trigger or exacerbate many lung conditions, including chronic cough, asthma, bronchitis, pneumonia and scarring of the lungs. Of these, chronic cough and asthma are the most common.
How Acid Gets Into the Lungs and Airways
Aspiration from acid reflux occurs when digestive liquids escape from the stomach, seeping and splashing up into into the esophagus and throat. While acid reflux may cause irritation there, normally the liquid would drain down and be reswallowed, returning it to the stomach. But when there's a glitch in swallowing mechanism, reflux can be sucked into the trachea, or wind pipe, and into the main airways of the lungs and beyond. This is called aspiration. In addition to being acidic, the aspirated liquid may contain secretions, bacteria and food particles. Aspiration can damage the lungs by causing inflammation, infection and scarring. Common symptoms of aspiration include coughing, wheezing and choking.
Asthma and chronic cough are the 2 most common lung-related problems linked to reflux, and some chronic coughs are actually a form of asthma. Reflux is thought to trigger asthma symptoms in 2 ways: directly and indirectly. When aspirated, acid particles can directly contact the windpipe to trigger wheezing. Even without direct lung contact, however, reflux may trigger asthma through a nervous system reflex: Acid irritates certain nerves of the esophagus, causing airways in the lungs to reflexively contract, obstructing airflow. Research published in the June-September "Annals of Thoracic Medicine" found that symptoms of GERD were present in 59 percent of asthma patients. The relationship between GERD and asthma is complex and can go both ways -- having asthma, or taking certain asthma medications, might contribute to GERD symptoms, as well.
GERD is one of the many causes of a persistent cough. As with asthma, 2 different effects of acid reflux are thought to trigger chronic cough: acid particles coming directly in contact with airways through aspiration and an indirect triggering of the cough reflex by irritating nerves in the esophagus. When tiny particles of reflux matter splatter onto the voice box and airways, this can cause inflammation and damage that leads to cough and hoarseness, often without producing the usual symptoms of GERD. This can account for 10 to 15 percent cases of unexplained chronic cough. Acid-suppressing medication may help some people with persistent cough, but predicting which individuals will benefit can be a challenge for doctors.
Aspirating large amounts of gastric acid can cause a chemical burn of the airways and lungs, leading to restriction of airways, fluid retention in the lungs and a form of pneumonia known as aspiration pneumonia. This is more likely to occur in people whose lung function is compromised, with advanced age, or in people whose swallowing is impaired -- after a stroke, for instance. Aspiration pneumonia is treated with antibiotics and other drugs. Symptoms include fever, weight loss and a cough that produces a foul or bad-tasting sputum.
Other Respiratory Conditions
Patients with inflammation of the esophagus from acid reflux have a slightly higher risk for other respiratory problems. People GERD symptoms are twice as likely to experience exacerbations of their chronic obstructive pulmonary disease, or COPD, than those without it and are twice as likely to be hospitalized. It has also been shown that people with GERD have a somewhat higher incidence of idiopathic pulmonary fibrosis, or IPF, a disease that causes lung tissue to become thick, stiff and ultimately rendered unable to function by scarring. The direct cause of IPF, however, remains unknown.
Precautions and Next Steps
Aspiration of gastric fluids into the lungs is a serious condition that requires medical attention. If you think reflux may be a factor in your respiratory condition, talk to your doctor. Acid-neutralizing drugs called proton pump inhibitors, or PPIs, benefit certain people with respiratory problems related to acid reflux, including some people with asthma and chronic cough. Because acid reflux-related aspiration tends to be more severe at night, head-of-the-bed elevation is recommended because gravity helps keep gastric fluids in the stomach where they belong. Losing extra weight is another lifestyle change that can help.