It is a very common finding that many patients complaining of asthma also suffer from Gastro Esophageal Reflux Disease. The two conditions are totally different yet there might be some thin association. First we will see each of them separately followed by a discussion on the gut-lung connection.
- It a chronic inflammatory condition of the airways inflicting 6 million children and 12 million adults in America. The symptoms are shortness of breath, cough, wheeze and chest tightness following an exposure to some allergen or following exercise when it is called exercise-induced asthma.
- Both envioronmental and genetic causes are involved in the causation of the disease. The exacerbations are due to allergens like pollen, house dust, animal dandler, mold and cigarette smoke.
- The diagnosis is made following clinical examination, chest x-ray and spirometry which give us an idea of the different lung volume.
Gastro-Esophageal Reflux Disease (GERD)
- It is condition where there is repeated eructation of acid and other contents of the stomach into esophagus causing heart burn as the most common spmtom. If the acid goes up to the mouth we feel a sour taste called water brush.
- The other sympotoms include epigastric pain, sore throat, cough, laryngitis, hoarseness and may even cause asthma which we will discuss later.
- Clinical examination may give a rough idea of the presence of the disease but to confirm the diagnosis we need to perform a 24 hours pH monitoring test.
- The cause of GERD is a lax Lower Esophageal Sphincter (LES) which causes the content to reflux back into the esophagus. Hiatus hernia, excessive smoking and pregnanacy are some of the predisposing condition.
- Another cause is the undigested carbohydrate which is fermented by the gut bacteria and produces a lot of gas like methane and hydrogen which pushes the acid and stomach contents up the esophagus.
The Gut-Lung connection
- The acid in stomach is useful to us as it inhibit harmful bacterial growth. In patients of GERD long term use of acid suppressing drugs lead to breakdown of this natural barrier to bacteria. Hence increased gut bacilli cause increased gas production; leading to more reflux, thereby forcing these up through esophagus into larynx then into the lung.
- Studies have revealed increased risk of pneumonia in patients under acid suppressing medication.
GERD and Asthma
- Multicentric trials using potent Proton Pump Inhibitors like rabeprazole and lanzoprazole were carried out to see whether their use leads to decrease in asthma symptoms. The study results showed no effect of PPI’s on decreasing asthma symptoms.
- This assumption is not wholly correct as the main cause of GERD is not the acidic pH of the stomach. Instead the main reason lies in the increase bacterial flora in the gut producing gases.
- Hence another trial was carried out by researchers from Imperial College London where telithromycin antibiotic was used is patients presenting with exacerbation of asthma. The study subjects showed greater symptomatic relief than control group. Thus confirming links between asthma and bacterial involvement in the process.
- The gut bacteria which reached the airways through reflux seem to explains all the findings.
More than 75% of patients are facing troublesome asthma bouts due to GERD and frequent heartburn; in fact some of the asthma medications can trigger symptoms of GERD; therefore it is the best options to consult a physician and treat the condition if you are suffering from both.