Asthma and gastro-oesophageal reflux

The asthma-GORD connection

Asthma and gastro-oesophageal reflux disease (GORD) often occur together and medical researchers have been trying to unravel the connection. Does one condition trigger the other and which comes first?

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 (your gullet or ‘food pipe’) and irritate it. It is the most common cause of heartburn and indigestion in Western society.

Many people with asthma also have gastro-oesophageal reflux and have an abnormal result with 24-hour oesophageal pH monitoring – a test that measures whether stomach acid is coming back into your oesophagus.

Conversely, people with reflux have an increased incidence of respiratory symptoms associated with asthma, such as cough, shortness of breath, wheeze and tightness in the chest.

Does acid reflux trigger asthma symptoms?

Researchers have yet to explain exactly how the 2 conditions are linked, but acid reflux can make asthma symptoms worse and trigger asthma, especially if it’s severe.

Does treating reflux improve asthma?

So, if reflux triggers asthma, you would expect that treating reflux would also ease asthma symptoms. In some cases this is true, yet some studies using proton pump inhibitors (medicines which suppress stomach acid) have shown no real improvement in asthma symptoms. For this reason proton pump inhibitors are not recommended, unless you specifically have a diagnosis of GORD.

If you have been diagnosed with GORD you should follow your doctor’s instructions on treatment to manage your GORD symptoms and also try self-help measures. If your GORD symptoms are uncontrolled, your doctor may wish to refer you to a specialist for assessment.

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 the mechanism of how GORD could provoke asthma symptoms.

  • During reflux of stomach contents into the oesophagus and throat, stomach acid may be aspirated into the airways, causing irritation and inflammation, which in turn may cause tightening of the airways and provoke an asthma attack.
  • Stomach acid which has refluxed into 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.

Who gets GORD-related asthma?

Both adults and children can have co-existing asthma and acid reflux.

GORD (acid reflux) is more common in people with asthma than the general population. Adults with hard-to-treat asthma are even more likely to have acid reflux.

In children, half of all children with asthma are estimated to also have acid reflux. Acid reflux may be a strong asthma trigger in babies and young children. With their underdeveloped digestive systems, babies are prone to reflux.

Can asthma provoke reflux symptoms?

Conversely, 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.

Do asthma medicines trigger reflux?

Some of the medicines used to treat asthma have been shown to promote acid reflux because they relax smooth muscles and so lower the pressure of the lower oesophageal sphincter – the bundle of muscles which normally prevents stomach acid refluxing back into the oesophagus. Prolonged relaxation of the lower oesophageal sphincter has been shown to cause increased reflux.

Beta2 agonist (reliever) medicines and theophylline (rarely used now – brand name is Nuelin) can relax the smooth muscles of the lower oesophageal sphincter, allowing acid to flow back into the oesophagus, resulting in reflux symptoms.

What should you do if you think reflux is triggering your asthma?

If you suspect you have reflux-related asthma symptoms, such as wheeze, cough or shortness of breath, you should see your doctor. He or she can diagnose your condition and provide a management plan and treatment for you.

Not everyone with GORD has typical heartburn symptoms, if you have ‘silent’ GORD you may not realise you have reflux. However, research suggests that in patients without symptoms of reflux, acid reflux is not a big factor in provoking asthma.

Clues that your asthma may be related to reflux are that:

  • you suddenly develop asthma as an adult;
  • your asthma is not well controlled with medications;
  • you get reflux before asthma symptoms start; or
  • your asthma gets worse after large meals, when you lie down or with alcohol.

What’s the treatment if you have reflux and asthma?

If you have asthma and have been diagnosed with gastro-oesophageal reflux, your doctor will advise you on treatment for your reflux. There is debate whether this can improve control of asthma symptoms, but it’s important to discuss it with your doctor and follow your doctor’s recommendations.

Increasing certain treatments for asthma symptoms (beta2 agonists and theophylline) may increase reflux, which itself can aggravate asthma symptoms, so a fine balance needs to be struck.

Adults with asthma who have uncontrolled reflux may be referred to a specialist for assessment. In some cases (rarely) they may suggest surgery to manage the reflux.

References

1. National Asthma Council. Australian Asthma Handbook. Gastro-oesophageal reflux disease and asthma. https://www.asthmahandbook.org.au/clinical-issues/comorbidities/gord
2. UpToDate. Gastroesophageal reflux and asthma. October 2019. https://www.uptodate.com/contents/gastroesophageal-reflux-and-asthma
3. Asthma and Allergy Foundation of America. Asthma and Gastrooesophageal reflux disease. 2020. https://asthmaandallergies.org/asthma-allergies/asthma-and-gastroesophageal-reflux-disease/
4. Ates F, Vaezi MF. Insight into the relationship between gastrooesophageal reflux disease and asthma. Gastroenterol Hepatol 2014; 10 (11): 729-36. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5395714/#!po=11.3636

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