Asthma and GERD are often found together, especially in patients with uncontrolled asthma. There are allegations that GERD (gastroesophageal reflux disease) is one of the factors that trigger asthma attacks. However, until recently, the mechanism that explained the relationship between the two was still only a theory.

Can GERD Trigger the Asthma Attack?


What are Asthma and GERD?

Asthma is a chronic inflammatory disease of the respiratory tract associated with airway hyperresponsiveness and causes wheezing symptoms, shortness of breath, and coughing. About 4.3% of people in the world experience asthma, and its prevalence is increasing every year. Gastroesophageal reflux disease (GERD) is a pathological condition resulting from the reflux of stomach contents into the esophagus with various symptoms (e.g., heartburn) arising from the involvement of the esophagus, larynx, and airways.



Basic Theory of the Effects of GERD on Asthma

The esophagus and lungs have a common embryonic origin and are innervated by the vagus nerve to be related theoretically. Exposure to acid in the esophagus or upper airway is thought to trigger bronchospasm and increase airway activity. These events can arise from the presence of a vagal reflex or microaspiration of gastric contents into the respiratory tract.

Patterson et al. performed an observational study in 32 patients with mild asthma and chronic cough. This study's results indicate a significant association between acid exposure in the distal esophagus and increased substance P and neurokinin A levels. This indicates that sensory nerve activation leads to poor control of asthma in patients with GERD.

Microaspiration of gastric content will also increase resistance in the respiratory tract. Direct contact with acidic aspirate can injure the respiratory tissue's epithelium, triggering inflammatory cytokines' release. Histology of the respiratory tract's inflammation induced by GERD shows infiltration of neutrophils, lymphocytes, eosinophils, and macrophages.

Besides that, asthma medications such as beta 2 agonists can also cause relaxation of the lower gastroesophageal sphincter, aggravating reflux and irritating the airways, causing recurrent coughing in asthma patients.



Diagnosis of Asthma with GERD

Asthma accompanied by GERD (gastroesophageal reflux disease) can be suspected if:
  • Appears for the first time as an adult
  • Have poor control over asthma medications
  • There are symptoms of heartburn or regurgitation before an asthma attack.
  • The worsening of asthma symptoms after consuming large amounts of food, drinking alcohol, or after lying on the back
  • Chronic cough at night in asthma patients

According to the 2018 GINA (Global initiative for asthma) guidelines, screening for GERD in uncontrolled asthma patients has no significant advantage. If an asthma patient is suspected of having a comorbid GERD, an empiric anti-reflux drug administration test can be performed.  If symptoms are not relieved, specific tests such as 24-hour pH monitoring and endoscopy may be considered.



Can Therapy for Gastroesophageal Reflux Improve Control of Asthma?

A systematic review by Cochrane reports that studies that find an association between asthma and GERD (gastroesophageal reflux disease) have many drawbacks, such as:
  • the absence of asthma or GERD diagnosis objective evidence, 
  • too few subjects (<60), 
  • and short term therapy (<3 months). 
This systematic review concluded that anti-reflux therapy did not improve symptom control in asthma patients.

Another study, a randomized clinical trial (RCT), reported similar results. This study conducted intervention and randomization on 207 study subjects. Interventions were given in the form of placebo or 2 x 30 mg of lansoprazole for 24 weeks. This study concluded that lansoprazole did not improve control of asthma symptoms, lung function, or the need to use salbutamol. However, this intervention was reported to significantly reduce asthma exacerbations and improve patients' quality of life, especially in patients using more than one controller.

Another more recent RCT (2010) in 828 study subjects intervened to administer 40 mg of esomeprazole once or twice daily for 26 weeks. This study concluded that twice-daily use of esomeprazole improved FEV1 and quality of life for patients statistically significant, but these improvements were minor and not clinically significant.

In GINA's guidelines (Global initiative for asthma) 2018, if a patient with asthma complains of a chronic cough, especially only at night, GERD's comorbidity must be considered. However, recommendations for administering anti-reflux drugs in uncontrolled asthma only when evidence of symptomatic reflux is found.



Summary
In patients with asthma that are difficult to control, GERD (gastroesophageal reflux disease) is suspected of being one of the influencing factors. Exposure to acid in the esophagus or upper airway is thought to trigger bronchospasm and increase airway activity. It is influenced by the vagal reflex or microaspiration of stomach contents into the respiratory tract.

GERD screening in patients with uncontrolled asthma has no significant advantage. If an asthma patient is suspected of having comorbid GERD, an empiric anti-reflux drug administration test can be performed, the same as in the general population. If symptoms are not relieved, specific tests such as 24 hour pH monitoring and endoscopy may be considered.

Existing studies show that GERD management in asthma patients with poor control does not improve symptom control and pulmonary function but has reportedly improved patients' quality of life. The 2018 GINA guidelines recommend implementing anti-reflux drugs in uncontrolled asthma only when evidence of symptomatic reflux is found.


References
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2. Gibson PG, Henry RL, Coughlan JL. Gastro-oesophageal reflux treatment for asthma in adults and children. Cochrane Database Syst Rev. 2000;(2): CD001496
3. GINA (Global Initiative for Asthma). Global strategy for asthma management and prevention, 2018. Available from: www.ginaasthma.org
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