Most of the time, just hearing a parent’s story and seeing a child is enough to make the diagnosis of gastroesophageal (GE) reflux, but sometimes testing may be recommended. These tests are most commonly used to diagnose GE reflux:
This special x-ray test allows doctors to follow food down the baby’s esophagus, through the stomach, and into the first part of the small intestine. The baby is fed a chalky-white liquid called barium. A video x-ray machine follows the barium through the upper intestinal tract and lets doctors see if there are any abnormal twists, kinks or narrowings of the upper intestinal tract. This test does not, however, give doctors much information on how the intestine works when food is in it, so it is not a very reliable way of diagnosing reflux.
Note: Many children with severe reflux symptoms will not demonstrate reflux on a barium swallow (poor sensitivity) and conversely, children who demonstrate reflux on a barium swallow may have no symptoms of gastroesophageal reflux (poor specificity).
Perhaps more important, the severity of reflux observed on a barium swallow does not help to predict the severity of symptoms of reflux nor does it help to predict the ultimate outcome. Fewer than 30% of adults with symptoms of chronic GE reflux demonstrate reflux on a barium swallow, and fewer than 30% of adults with esophagitis as a result of chronic reflux demonstrate reflux on a barium swallow.
With this test, the infant drinks milk mixed with technetium, a very weakly radioactive chemical, and then the technetium is followed through the intestinal tract using a particular type of camera. This test is helpful in determining whether some of the milk/technetium ends up in the lungs (aspiration). It may also be helpful in determining how long milk sits in an infant’s stomach.
With this test, a small wire with an acid sensor is placed through the infant’s nose down to the bottom of the esophagus. The sensor is usually left in place for 12-24 hours. It can detect when stomach acid “refluxes” into the esophagus. This information is generally recorded on a computer. At the conclusion of the test, we can determine how often the infant “refluxes” and whether there are any symptoms when this occurs.
Unfortunately, the severity of reflux as measured by pH probe often doesn’t correlate with the severity of symptoms . . . that is, some infants with very frequent vomiting will have a normal pH probe study. Perhaps more important, the severity of reflux measured by a pH probe does not help to predict the ultimate outcome. Although pH probe analysis is abnormal in nearly 80% of infants with mild reflux symptoms (i.e. occasional spitting and vomiting), one third of infants with severe symptoms have a normal pH probe study! Also, fewer than 40% of infants with severe esophagitis due to chronic reflux will have abnormal pH probe studies.
Perhaps the greatest potential value of pH probe analysis is in trying to correlate reflux with unusual or persistent symptoms such as apnea, stridor, coughing or wheezing, choking, gagging, or unexplained irritability. If these symptoms occur frequently enough, a pH probe analysis can determine if these symptoms occur at the same time as episodes of acid reflux.
This is the most invasive test. A flexible endoscope with lights and lenses is passed through the infant’s mouth into the esophagus, stomach, and duodenum, allowing a direct look to see if there is any irritation or inflammation. In some children with reflux, repeated exposure of the esophagus to stomach acid causes some inflammation (esophagitis). The greatest problem with this test is that most infants with reflux symptoms do not develop esophagitis (less than half with severe symptoms have esophagitis at endoscopy), so a normal test does not necessarily mean the child does not have reflux.
As you can see, none of these tests is perfect. Each has strengths and weaknesses and provides different information.
In most cases, diagnosis of GE reflux can be made clinically based on a careful history and physical examination of the child.
In a child whose development is delayed or disordered, it is appropriate to consider reflux when the child:
- suffers from recurrent pneumonia or aspiration,
- is chronically irritable without any apparent explanation, or
- does not grow well despite receiving adequate numbers of calories
Diagnostic tests are primarily useful when trying to associate these types of unusual or severe symptoms with reflux, but offer little information about the ultimate outcome or appropriate treatment strategies.