Asthma Subgroups: GERD Asthma
Way back in 1985, when I was a fifteen-year-old asthmatic with high risk asthma, I underwent testing to see if I had gastroesophageal reflux (GERD). Thankfully, I did not have this, back then anyway. An asthmatic friend of mine did, and the diagnosis made a huge difference in his life, because treatment for GERD allowed him to obtain better asthma control. Today, the relationship between GERD and asthma is well understood to the point that it has become it’s own asthma subgroup aptly called GERD asthma.
What is GERD?
Like asthma, GERD is considered a syndrome rather than a disease. After you chew and swallow food it moves down your esophagus, through an esophageal sphincter, and into your stomach. The esophageal sphincter allows food into your stomach and prevents it from going back up. However, certain instances can occur when this muscle relaxes, allowing stomach contents to move backwards up the esophagus, a process called reflux or acid reflux.
Certain foods or drinks, such as chocolate, peppermint, cinnamon, deep-fried foods, spicy foods, coffee and alcohol, can cause the esophageal sphincter to relax, causing acid reflux. It can also be caused by obesity or hiatal hernias.
In fact, About 90% of people diagnosed with GERD also have hiatal hernias, which is when a portion of your stomach protrudes through a small opening in your diaphragm.1
It may also be caused by side effects to certain medicines, such as systemic corticosteroids.
Symptoms include heartburn, chest pain, difficulty swallowing, belching, coughing and feeling bloated after eating. Symptoms are silent (not observed) in about 75% of GERD sufferers.
What is GERD asthma?
A link between asthma and GERD was first recognized in 1909 by Dr. Henry Osler who wrote, “The (asthma) attacks may be due to direct irritation of the bronchial mucosa, or may be induced… indirectly, too, by reflex influences from the stomach.”2
Studies showing a link between the two diseases first started appearing in the mid-1970s.
Studies show a whopping 75% of asthmatics have GERD, and that asthmatics are 50% more likely to develop GERD than non-asthmatics. So Osler’s theory is now well established. Those with severe asthma, or asthma resistant to traditional asthma medicines, are increasingly likely to develop GERD.3
Asthma GERD is a non-allergic, or intrinsic, subgroup of asthma. When diagnosed in non-allergic asthmatics, GERD tends to be poorly responsive to asthma rescue and controller medicines, and is therefore considered difficult to control, or severe asthma. At the present time, it is unknown whether GERD treatment results in better asthma control.4,5
It is generally considered an adult-onset disease, although it may also be diagnosed, as noted above, in childhood. While an asthma subgroup of it’s own, it can also be a secondary diagnosis to other asthma subgroups, particularly allergic asthma and obese asthma.
What causes it?
There are at present three theories.
GERD causes airway hyper-responsiveness
Chances are that it begins with asthma genes. Chronic (day after day) exposure to some environmental factor (in this case aspiration of acid reflux) activates (turns on) asthma genes, and this causes the immune system to recognize the substance as harmful. This results in the initiation of an immune response that ultimately leads to the release of T-helper 2 cells that ultimately lead to the release of inflammatory markers that cause airway inflammation and asthma.4 This makes airways hypersensitive (twitchy) in response to asthma triggers (one of which may be the acid reflux itself), resulting in airway narrowing and airflow limitation that is reversible and controlled with asthma rescue medicine and inhaled corticosteroids (often high doses).
GERD causes direct bronchospasm
This interesting theory postulates that the esophagus and bronchioles share some of the same nerves. Microscopic amounts of acidic stomach content enters the airway (aspiration) and irritates your esophagus. A signal is then sent via nerve pathways to bronchioles thereby irritating them and causing them to spasm (bronchospasm). This is how acid reflux may indirectly cause bronchospasm, or so the theory goes. This mechanism is referred to as the “vagally mediated reflex.”5This theory essentially asserts that acidic stomach contents do not have to be inhaled into the lungs to cause asthma, all it has to do is irritate the esophagus.6 This response may also be a natural response to prevent pathogens from entering the airways (in this case, stomach contents are mistaken for pathogens).
Asthma causes GERD
Another theory postulates that bronchospasm may cause GERD. While I’ve read about this in several articles, I have yet to find a credible explanation for it. Another theory is that medicines used to treat asthma may cause GERD. For instance, systemic steroids are known to cause reflux. An older asthma medicine, one sometimes still used for difficult to treat asthma, is theophylline. It works similar to caffeine and may relax the esophageal sphincter. Bronchodilaors like albuterol may also cause the esophageal sphincter to relax, resulting in GERD.7
How is it diagnosed?
GERD asthma is a common cause of adult-onset asthma, although it can also be diagnosed in childhood. When asthma is suspected, and traditional medicines do not work, then GERD should be suspected. This is especially true when allergic asthma has been ruled out, and asthma symptoms are worse at nighttime. It should also be suspected whether or not the patient complains of GERD symptoms.8
Diagnosis can be made by a good history, although it can also be diagnosed by tests, such as:
A tube is inserted through your nose into your esophagus, and a machine measures acid content while you are sleeping. I had this done in 1985, and I passed.
A drink containing barium is swallowed, and this coats your esophagus. An x-ray is then taken to check for any esophageal abnormalities. I also had this done in 1985, and I passed.
Under sedation, a physician inserts a tube into your esophagus through your mouth to check for any abnormalities inside your esophagus and stomach. This is usually how a hiatal hernia is diagnosed, and usually proves a diagnosis of GERD. Thankfully I did not have this done as a child, although as an adult I was diagnosed with a hiatal hernia and GERD.
GERD asthma treatment
Most asthma guidelines at the present time treat asthma as a single disease, where every asthmatic is treated the same. In the future, there may be asthma guidelines specifically tailored to asthma subgroups, such as GERD asthma.
At present, there are no medicines unique to GERD asthma. What is recommended are asthma controller and rescue medicines and possibly GERD treatment.5
My asthmatic friend from back in 1985 had the head of his bed elevated about 30 degrees, and this prevented reflux while he slept. He was also put on a special diet and was encouraged to exercise regularly and lose weight. Treatment today is not much different, and involves elevating the head of your bed, weight loss, and a diet that eliminates alcohol, caffeine, smoking, and carbonated beverages. It is also recommended to eat small meals, and to eat 2-3 hours before lying down to sleep. Treatment may also involve over the counter or prescribed medicine to reduce stomach acid and prevent reflux.1,7
I developed GERD asthma in adulthood, although your guess is as good as mine whether it is secondary to my Allergic Asthma, medicines used to treat it, or it getting it was merely coincidental. I do believe asthma can cause GERD, and this may be the case with me, especially considering I have had it bad in the past, and have utilized both steroids and theophylline for long periods of time. I also believe the opposite could happen as well, that GERD can cause asthma. Some researchers believe the link is merely coincidental. Either way, it will be neat to see what future research shows. So, now that we are educated about GERD asthma, what are your thoughts?
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