Asthma and gastric reflux
The asthma-GORD connection
Recent medical research has been trying to unravel the connection between 2 very common conditions: asthma and gastro-oesophageal reflux disease (GORD, also known as GERD). GORD is a condition in which the acidic contents of your stomach (partially digested food and acid) regurgitate or reflux (wash back) into the oesophagus (the gullet). It is the most common cause of heartburn and indigestion in Western society.
Many people with asthma also have gastro-oesophageal reflux, leading researchers to believe that reflux might be a trigger for asthma, or that asthma might trigger reflux.
Does reflux trigger asthma symptoms?
Researchers have yet to explain exactly how the 2 conditions are linked. Although many people have both asthma and reflux, they still can't say conclusively that reflux triggers asthma.
For example, if reflux triggers asthma, you would expect that treating reflux would also ease asthma symptoms. Yet some studies have shown no real improvement in asthma symptoms and no real effect on the need for asthma medication after treatment for reflux.
On the other hand, some studies have shown that treatment of reflux (by either medical or surgical means) resulted in improvement in asthma symptoms.
So far, the evidence is not definitive. A recent review of research trials has found that, although some people's asthma did improve as a result of treating their reflux, it isn't possible to predict which people will benefit.
How could reflux provoke asthma symptoms?
Although researchers admit that the evidence is often conflicting and more studies need to be done into the connection between the 2 conditions, they have 2 main theories for how GORD could provoke asthma symptoms.
- During reflux of stomach contents into the oesophagus and throat, stomach acid may get into the airways, causing irritation and inflammation, which in turn may cause tightening of the airways and provoke an asthma attack.
- Stomach acid in the oesophagus, as it inflames and sometimes ulcerates into the tissue, may expose nerve endings and over-stimulate the vagus nerve, which supplies both the oesophagus and the lungs. Over-stimulating the vagus nerve might cause lung airway muscles to go into spasm as they do in an asthma attack.
Can asthma provoke reflux?
Some researchers have indicated that the narrowing of the airways in asthma may be responsible for reflux or may aggravate reflux, although exactly how it does this is not yet clear. It may be that people with asthma have abnormalities in the way that their autonomic nervous system (which helps control lung and gut function) works. Or there may be abnormalities in the way their diaphragm functions, or in the pressure gradient between the abdomen and the chest - a high gradient could push acid into the oesophagus.
Other researchers have shown that the link between asthma and reflux could be explained by the use of beta2 agonist (reliever) medicine or theophylline (Nuelin) for asthma. They say that these medicines could relax the smooth muscles of the lower oesophagus, allowing acid to flow back into the oesophagus, resulting in reflux symptoms.
Treating reflux to help treat asthma
Doctors believe that some people who have asthma and symptoms of reflux might benefit from being treated with anti-reflux medicine to see if their asthma improves. Other techniques that may help reflux are avoiding eating and drinking in the 2-3 hours before you go to bed (particularly avoid heavy meals, fried food, coffee and alcohol), and raising the head of your bed on blocks of about 15-20 cm.
However, although some studies have shown that asthma symptoms improve after treatment for reflux in some people with asthma, lung function itself does not seem to get any better.
Evidence for the effectiveness of this treatment is still under discussion.
What can you do?
If you suspect you have reflux-related asthma symptoms, you should see your doctor. He or she can diagnose your condition and provide a management plan and treatment for you.
Clues that your asthma may be related to reflux are that:
- you suddenly develop asthma as an adult;
- your asthma is worse at night;
- your asthma gets worse after meals, when you lie down or when you exercise;
- your asthma is hard to control despite treatment.
2. Gibson PG, Henry R, Coughlan JJL. Gastro-oesophageal reflux treatment for asthma in adults and children. Cochrane Database Syst Rev 2003; 1: CD001496. doi: 10.1002/14651858.CD001496. http://onlinelibrary.wiley.com/o/cochrane/clsysrev/articles/CD001496/frame.html (accessed Dec 2010).
3. National Heart, Lung, and Blood Institute, National Institutes of Health (US). Expert panel report 3 (EPR3): Guidelines for the diagnosis and management of asthma. NIH Publication No. 07-4051 (last revised Aug 2007). http://www.nhlbi.nih.gov/guidelines/asthma/asthgdln.htm (accessed Dec 2010).