Is there differences between a hiatal hernia with acid reflux and GERD or are they the same thing?
They are the same thing.
Often referred to by the shorter names “acid reflux” or simply “reflux,” gastroesophageal reflux disease (GERD) is a common condition, usually in conjunction with a weakness of the ring of muscle (hiatal hernia) that prevents stomach acid from backwashing up into the delicate esophagus.
The diagnosis of GERD is made during X-rays of the upper gastrointestinal tract or by endoscopy (viewing the esophageal and gastric linings through a fiber-optic tube).