Non-Acid Reflux Disease: How is it Diagnosed?
Guest: Dr. Donald Castell – Gastroenterology-Hepatology
Host: Dr. Linda Austin – Psychiatry
Dr. Linda Austin: I am Dr. Linda Austin and I am talking with Dr. Donald Castell who is Director of the Esophageal Disorders programs. Dr. Castell, we have been talking about non-acid reflux disease. How do you diagnose that?
Dr. Donald Castell: That is a very important question, primarily, because most of our approaches to date have used the acid as the vehicle that we measure. So, once you treat for the acid and eliminate its presence, then detecting the ongoing reflux is a bigger challenge. We use a technique called impedance measurements where we actually measure the electrical circuit, or the electrical change, in the esophagus that is produced by the movement of fluid up from the stomach. So, impedance tells us whenever any kind of liquid appears, independent of whether it is acid or non-acid, or what its acidity happens to be.
Dr. Linda Austin: Can you describe the procedure by which you test that?
Dr. Donald Castell: Indeed. We, gastroenterologists, as I am sure you are aware, like to put tubes in various places. This procedure involves a very small catheter, a 2 mm diameter catheter, that we pass through the nose and into the stomach. Then we measure, at all levels, from the stomach up through the esophagus, the impedance value. Whenever reflux occurs, whenever any kind of liquid comes up from below, we will see very definite changes.
Dr. Linda Austin: Two mm, that is about, what, 0.1 inches? It is pretty tiny.
Dr. Donald Castell: It is pretty small.
Dr. Linda Austin: Yeah.
Dr. Donald Castell: It is amazing. It sounds kind of scary when somebody first suggests it but most people tolerate it very well.
Dr. Linda Austin: Really?
Dr. Donald Castell: We have them wear it for a day. Over a period of hours, they do not know it is there.
Dr. Linda Austin: Really? So, it is pretty easily done and then they can get the answer?
Dr. Donald Castell: Yes. The important thing is that even though there is some level of discomfort or embarrassment, maybe, by having this catheter coming out of your nose, it gives information that is otherwise not available.
Dr. Linda Austin: Is this a once in a lifetime kind of diagnostic procedure?
Dr. Donald Castell: Most of the time.
Dr. Linda Austin: What are the exceptions to that? When might you repeat it?
Dr. Donald Castell: The exceptions are the occasional patient where, for whatever reason, the recording did not work or the battery was bad. Fortunately, that is under one percent. Most of the time, yes, it is just a once in a lifetime procedure.
Dr. Linda Austin: Did you develop that procedure?
Dr. Donald Castell: Yes. We actually developed it here, at MUSC. Over the last five years, we started with initial prototypes that were not very accurate and we made a lot of changes in design. We tested in volunteer subjects until we got it to the point where we felt it was ready to be applied to patients. For the last three to four years now, we have tested it regularly in many patients, about 500 or 600.
Dr. Linda Austin: Through clinical trials then?
Dr. Donald Castell: Through clinical trials, yes.
Dr. Linda Austin: So, that really speaks to the importance of participating in clinical trials if you have the opportunity.
Dr. David Castell: Yes. We are very fortunate because it is a university center. I think many of the patients that are referred to us are pretty well tune in to the fact that, well, maybe there will be a trial going on or maybe I can contribute in some way by being a part of a trial. I find the patients here very willing to participate.
Dr. Linda Austin: And I am sure you make it very easy for them to do so.
Dr. Donald Castell: Well, we try to.
Dr. Linda Austin: They are very important people, true VIPs.
Dr. Donald Castell: Yes. Indeed, they are.
Dr. Linda Austin: Dr. Castell, thank you so much.
Dr. Donald Castell: You are quite welcome.
If you have any questions about the services or programs offered at the Medical University of South Carolina or if you would like to schedule an appointment with one of our physicians, please call MUSC Health Connection: (843) 792-1414.