Acid reflux is caused by the contents of the stomach traveling up the esophagus. The contents of the stomach are acidified by the production of gastric acid, which helps break down food and activates certain enzymes necessary for digestion. Normally, the gastric acid is kept out of the esophagus by a ring of muscle called the lower esophageal sphincter. If this sphincter malfunctions, it allows acid to travel up to the esophagus, burning the lining.
Diagnosis from Symptoms
In many cases, acid reflux can be diagnosed by talking to the patient about his symptoms. Acid reflux typically causes a burning pain to develop in the patient's chest. In some cases, a patient may regurgitate some of the acid into the back of her throat or mouth. Acid reflux disease can be distinguished from other causes of chest pain by its tendency to occur after eating, particularly after the ingestion of large quantities of spicy, fatty or acidic foods. Acid reflux also can be exacerbated if the patient lies down. The initial diagnosis often is made based solely on these symptoms.
Esophageal pH Measurement
Doctors sometimes will attempt to determine the pH (a measurement of acidity) of the patient's esophagus over a 24- or 48-hour period. For this procedure, a physician will lower a small device down the patient's esophagus to monitor and record the pH of the patient's esophagus over a period of time. The patient will then go through his normal daily activities (including eating) and write down when food or beverages were consumed, as well as any periods of time in which he was reclining. After 24 or 48 hours, the physician will remove the device and look for sudden drops in pH, which could signal acid reflux.
Barium Swallow
Another type of test that can be used to diagnose acid reflux is called an upper GI series. The patient stands in front of an X-ray machine and drinks a solution containing barium. The barium flows through the esophagus and the rest of the digestive tract, coating the linings of tissues. Because the barium absorbs X-rays, it will make it easier to see the insides of the esophagus. This allows a radiologist to look for damage caused by acid reflux and can help diagnose the underlying cause. Often doctors will use fluorimetry, essentially an X-ray video, to better see the barium as it flows through the body.
Double Contrast
A double contrast study is very similar to the barium swallow test, but the patient also swallows crystals that will react with the barium and produce gas. This gas will cause the stomach to expand, which can allow for more detailed observations. Double contrast studies typically are done using fluorimetry.
Endoscopy
When doctors perform an endoscopy, they insert a small flexible camera down the patient's esophagus, which allows them to look at the tissue of the esophagus and stomach. The physician can study the video and look for any esophageal ulcers or scar tissue, as well as any abnormal structures that contribute to the acid reflux. If the physician is concerned that part of the esophagus is becoming cancerous, she can use special tools to remove a small piece of tissue for later examination under a microscope.
