Gastroesophageal reflux disease (GERD) has been linked to many forms of pulmonary disease, including aspiration pneumonia, asthma, chronic cough and, more recently, idiopathic pulmonary fibrosis (IPF). Studies estimate that as many as 90% of patients with IPF may also have GERD.
However, because not all presentations of lung diseases include GERD's more commonly recognized symptoms, such as heartburn and regurgitation, it may be missed as a contributing factor. Instead, patients may present with asymptomatic GERD that can be recognized through respiratory symptoms or other extraesophageal symptoms.
Research to date has made it difficult to establish a cause-and-effect relationship between GERD and lung diseases, but experts say internists should be aware of the possible association between the two, methods for detecting both and strategies for managing the condition.
“The main thing for internists to recognize is that lung disease is an extraesophageal complication that can occur in patients with GERD, and that some patients with lung disease, even in the absence of GERD symptoms, may have GERD as the underlying cause,” said Jay H. Ryu, MD, professor of medicine at the Mayo Clinic in Rochester, Minn.
Links to lung diseases
The two more recognized aspiration diseases associated with GERD are aspiration pneumonitis and aspiration pneumonia.
Aspiration pneumonitis occurs when a large amount of regurgitated gastric contents and acids are aspirated into the lungs, causing chemical injury. The term “aspiration pneumonia” refers to a pneumonia infection that occurs in patients at risk for aspirating, such as patients who are debilitated and may aspirate food or oropharyngeal secretions into their lungs.
“What we are recognizing now is that there are more subtle forms of lung injury that occur from lung aspiration,” said Dr. Ryu. “Sometimes GERD and aspiration may not be associated with obvious symptoms, where patients may not be aware that they are aspirating and getting foreign matter into their lungs.”
Two pulmonary diseases associated with GERD are asthma and chronic cough. Aspiration due to GERD may cause these disorders in one of two ways, through direct aspiration or reflux injury, according to Maxwell Chait, MD, FACP, a gastroenterologist from ColumbiaDoctors Medical Group in Hartsdale, N.Y., and assistant professor of medicine at Columbia University College of Physicians and Surgeons.
“Acid reflux can also cause reflex arc through the nervous system for that area and cause the airways to go into reflex bronchospasm,” leading to asthma or chronic cough, Dr. Chait said.
A systematic review of 28 studies looking at the link between GERD and asthma, published in Gut in 2007, estimated that 59% of patients with asthma also had symptoms of GERD, compared with only 38% of control patients. However, the researchers concluded that there was a lack of data to determine the direction of causality.
Estimates of GERD as the primary cause of chronic cough range from 10% to 40%, but the literature linking GERD to chronic cough varies by the population being tested and the type of test used in GERD diagnosis.
“When evaluation for GERD is performed in patients with respiratory disorders, a large percentage demonstrate abnormal pH values on testing, and the patients with typical heartburn symptoms will often demonstrate better response to medical therapy,” said Lauren B. Gerson, MD, director of clinical research in the Division of Gastroenterology at San Francisco's California Pacific Medical Center and an author of the American College of Gastroenterology's guidelines on GERD. “However, an ongoing point of contention is the fact that we have been unable to establish causality. At this time, we have only been able to prove that the two conditions co-exist.”
Studies have also linked GERD to a particular form of interstitial lung disease called idiopathic pulmonary fibrosis (IPF), estimating that as many as 90% of patients with IPF may also have GERD. More recently, Joyce Lee, MD, an assistant adjunct professor or medicine at the University of California, San Francisco, and colleagues published a study that found that patients with IPF who used GERD medication had a median survival time that was twice that of patients who did not use the drugs.
Similar to the link between GERD and asthma and chronic cough, data showing direction of causality are lacking, and there are two opposing views about the link between IPF and GERD in the medical community, Dr. Lee noted.
“Those that believe there is a link between reflux, aspiration and pulmonary fibrosis think the reflux happened first and [patients] developed lung fibrosis as a consequence of chronic microaspiration over time,” Dr. Lee said. “The other camp would suggest that patients developed pulmonary fibrosis first and the pulmonary fibrosis and scarring on the lung places traction on the mediastinal structures, including the esophagus, leading to the reflux.”
Dr. Lee acknowledged that there is still a lot to learn about the link between GERD and IPF. For example, there is a significant difference in the number of people who have GERD and the number who have IPF, leading researchers to question what is different in the people who develop IPF compared with the rest of the population.
What to look for
Currently, there is no evidence that patients with GERD need to be actively screened for asthma or other pulmonary disorders, according to Dr. Gerson. Instead, patients who are known to have GERj14 should be asked periodically about the development of symptoms, such as shortness of breath or chronic cough, that may indicate an associated pulmonary complication.
Internists should be on the lookout for other important red-flag situations, added Dr. Chait: “Look for dysphagia, weight loss, anemia, severe abdominal pain and other symptoms which would be associated with concern of injury.”
The American College of Gastroenterology, meanwhile, recommends that GERD be considered as a potential co-factor in patients with asthma and chronic cough but that other non-GERD causes should also be examined.
If GERD is suspected in patients with lung disease, management is similar to that used for GERD alone.
Lifestyle modification is recommended, using tactics such as elevating the head during sleep and avoiding late-night meals; fried, fatty and spicy foods; and medication that can affect the lower esophageal sphincter, according to Drs. Chait and Ryu.
Dr. Gerson added that if lifestyle modifications do not work, the next step is typically using a proton-pump inhibitor for 2 to 3 months to see if symptoms improve.
“If pulmonary symptoms improve, patients can continue to use anti-reflux medications,” said Dr. Gerson. “If the symptoms do not improve, our guidelines recommend that physicians perform subsequent diagnostic testing.”
Testing could include an upper endoscopy, which may or may not show signs of erosion or evidence of damage but may detect other causes of the patient's symptoms, such as allergic esophagitis, which can trigger chronic cough.
Patients can also try temporarily stopping anti-reflux medications while they undergo esophageal pH monitoring for 24 to 48 hours to measure the level of acid reflux being produced. The pH testing can also be performed during medical therapy to determine if patients continue to reflux acidic or nonacidic material despite treatment.
“If the pH testing is abnormal, the physician can confirm that the patient has reflux disease but is still faced with the ongoing issue that he/she cannot guarantee the patient that treatment of GERD will help the patient's pulmonary condition.” Dr. Gerson said. “However, if the pH test is negative, then the physician can discuss with the patient that reflux disease is likely not present. In this situation, the anti-reflux medications can be stopped and evaluation of the patient for other causes of the symptoms should occur.”