You may have heard of GERD, otherwise known as gastroesophageal reflux disease, which covers many types of upsets like heartburn and indigestion. This has been found to be the cause of less than half of the reflux people suffer from. According to Dr. Patricia Raymond, far more people are living with NERD, which is non-erosive esophogeal reflux disease.
"At the top of your stomach is a flap that keeps juices down where they belong. It’s called the lower esophageal sphincter. That little flap is the problem for some people with reflux: It’s weakened and lets juices come up into the esophagus. Not so with NERD."
This condition does not cause ulcers or erosions, which is a good thing. But it does make it harder to identify and treat. As a matter of fact, doctors don't know yet how to treat NERD. But, Dr. Raymond assures us, they are working on that.
http://www.familydoctormag.com/digestive-health/1299-nerd-the-most-common-heartburn-and-what-to-do-about-it.html