Most people associate reflux with very characteristic symptoms, such as heartburn. However, reflux can also cause unspecific symptoms, such as cough, sore throat, and hoarseness. Because these symptoms are typically not associated with reflux, this kind of reflux is frequently called silent reflux. Less commonly, it is also known as airway reflux or respiratory reflux.
What is Airway Reflux?
Reflux typically refers to acidic stomach contents that rise into the esophagus. The acid irritates the esophagus, causing symptoms such as heartburn. Reflux can, however, also be a gaseous, or rather a fine mist and rise further up to the throat and airways. The term airway reflux is, therefore, a good description of the condition, although it is not commonly used. The corresponding medical term laryngopharyngeal reflux (LPR) is more common. It is composed of the words larynx (voice box) and pharynx (throat), describing the areas that the reflux affects most commonly.
The term silent reflux is often used by patients and refers to the unspecific symptoms of the condition. Because the symptoms are not associated with reflux, the disease often remains unrecognized, or silent, for a long time. It can thus take many years to receive a correct diagnosis. The term silent reflux is liked by patients because it is much easier to remember than the very medical term laryngopharyngeal reflux.
The terminology can be confusing. It sounds at first like all those terms might describe different types of reflux. However, this is not the case. LPR, silent reflux, airway reflux, and also respiratory reflux, all mean the same thing.
How Airway Reflux Causes Damage
Acid is often thought to be the cause of any kind reflux damage, but in the case of airway reflux, acid represents only one part of the equation.
When gaseous reflux rises into the throat and airways, it takes along with it pepsin. Pepsin is an enzyme from the stomach that plays an essential role in digestion because it breaks down proteins. Without pepsin, we would not be able to digest the protein from the meals we eat.
The activity of pepsin is pH-dependent, and it is most active at a low (acidic) pH. This makes sense, considering that the stomach is very acidic. The pH of the throat and airways is typically too high for pepsin to be active. Unfortunately, the reflux that carries along the pepsin is acidic, thereby lowering the pH of the airways. Furthermore, acidic foods and drinks passing down the throat can lower the pH and thus set the stage for activity by pepsin.
The activation of pepsin occurs in two phases:
- Initiation phase: Pepsin gets carried along with the
gaseous reflux. When it reaches the airways, it can attach to and penetrate the
cells of the mucous membranes and stays there for a while (hours to days). - Reactivation phase: Pepsin gets reactivated in the
presence of acid. The acid can either come from further reflux or from acidic
foods and drinks.
Once pepsin gets activated in or on the mucous membranes, it performs its job, namely digesting proteins. Unfortunately, our cells mainly consist of proteins. With this in mind, you can easily understand how pepsin causes tremendous damage to the membranes. The irritation of the mucous membranes by pepsin leads to inflammation and airway symptoms.[1]
This article explains in more detail how pepsin gets activated and causes damage to the airways.
How to Recognize Airway Reflux
Because respiratory reflux affects the airways, it causes unspecific symptoms that are usually more associated with a cold or a respiratory condition.
Common symptoms of airway reflux include[2]
- chronic cough;
- cough after eating;
- hoarseness;[3]
- frequent throat clearing;
- asthma or breathing problems;
- sore throat;
- ear pain;
- dry eyes;
- enamel erosion;
- frequent belching;
- aggravation of other respiratory diseases;
- swallowing problems (dysphagia);
- feeling of a lump in the throat;
- recurrent flu-like infections.
The article about LPR symptoms describes these symptoms in more detail.
A careful analysis of the symptoms is also a crucial part of the diagnostic process. The reflux symptom index (RSI) is a questionnaire that assesses airway reflux-associated symptoms in detail. The test is sometimes performed at a doctor’s visit, but you can also take the test online here on Refluxgate.
Some diagnostic tests can help to confirm the diagnosis, but there is no single test to diagnose reflux reliably.
This article provides more information about tests for the diagnosis of airway reflux.
Treatment of Airway Reflux
Three primary approaches exist for the treatment of airway reflux: diet, medication, and surgery.
Diet
Successful treatment has to address the cause of the symptoms. For most people, the most promising approach is a change in dietary habits. Dietary adaptations can reduce reflux symptoms in two ways:
- They can reduce the reflux itself, thereby limiting the amount of acid and pepsin reaching the airways.
- They can prevent the reactivation of pepsin by eliminating or minimizing acidic foods and drinks.[4],[5],[6]
This article about diet and airway
reflux provides more information about which dietary measures are most likely to be effective.
Medication
Liquid reflux irritating the esophagus can be treated with medications that reduce acid production. For this purpose, proton pump inhibitors (PPIs) are commonly used. Because the damage in airway reflux is primarily caused by pepsin, though, PPIs are not effective in treating this kind of reflux, and they are no more useful than a placebo, according to studies.[7]
This article provides more information about medications for airway reflux.
Surgery
Surgery can be effective in extreme cases, but for most people with airway reflux, such an invasive approach is not necessary. It always bears the risk of complications, and the success rate is much lower than for classical reflux.
You can learn more about this topic in the article about surgery for airway reflux.
References
[1] Johnston N, Dettmar PW, Bishwokarma B, Lively MO, Koufman JA. Activity/stability of human pepsin: implications for reflux attributed laryngeal disease. Laryngoscope. 2007;117(6):1036–9.
[2] Vaezi MF, Hicks DM, Abelson TI, Richter JE. Laryngeal signs and symptoms and gastroesophageal reflux disease (GERD): a critical assessment of cause and effect association. Clin Gastroenterol Hepatol. 2003;1(5):333–44.
[3] Lechien JR, Huet K, Khalife M, et al. Impact of laryngopharyngeal reflux on subjective and objective voice assessments: a prospective study. J Otolaryngol Head Neck Surg. 2016;45(1):59.
[4] Koufman JA. Low-acid diet for recalcitrant laryngopharyngeal reflux: therapeutic benefits and their implications. Ann Otol Rhinol Laryngol. 2011;120(5):281–7.
[5] Koufman JA, Huang S, Gelb M. Dr. Koufman’s Acid Reflux Diet: With 111 all new recipes including vegan & gluten-free: the never-need-to-diet-again diet. Katalitix. 2015.
[6] Koufman JA, Stern J, Bauer MM. Dropping acid: the reflux diet cookbook & cure. Reflux Cookbooks; 1st ed. 2010.
[7] Reimer C, Bytzer P. Management of laryngopharyngeal reflux with proton pump inhibitors. Ther Clin Risk Manag. 2008;4(1):225–33.