Relationship between GERD, hiatus hernia and esophagitis are complex. Occasional reflux occurs in all of us. It may be unnoticed, but one-third of people experience heartburn at least once a year, and 10% at least once a month. Whether or not a reflux episode causes heartburn and esophagitis depends the interactions of many factors. Only a few refluxers develops esophagitis, but many of those report no heartburn. Why GERD has such unpredictable and dichotomous consequences is unclear.
A hiatus hernia is a bulging or protrusion of part of the stomach through the diaphragm up into the chest. This occurs in about one-third of Western adults by the time they are 60 or 70 years old. Therefore, it is no surprise that hiatus hernia and heartburn often occur together. This coincidence led to the erroneous belief that a hiatus hernia causes heartburn, or even that a hiatus hernia is heartburn. A patient once referred to her heartburn as "my high anus hernia". In the 1950s to 1970s, surgeons commonly repaired a hiatus hernia for reflux symptoms
There followed a period when clinical scientists declared that GERD and hiatus hernia are merely coincidental. As evidence, they observed that reflux could occur without a hernia and that many with a hernia had no heartburn. As often happens, the truth lies somewhere between these two views. Newer work assumes us that a hiatus hernia may indeed impair LES activity. Thus a hiatus hernia may be an innocent bystander, it may contribute to reflux, or it may even be present.