Are hiatal hernias dangerous?

Very rarely.: A hiatal hernia is an enlargement of the normal opening in the diaphragm thru which the esophagus passes. Most people have no symptoms. For those that do, it usually causes heartburn due to the stomach yo-yo-ing up and down thru the hiatus. Rarely, the top of the stomach stays in the abdomen but the bottom flips up thru the hiatus, sometimes causing obstruction or bleeding, which can be serious.

Possible: They can be. Depends on size and symptoms.

Possible: Generally, only large hernias are potentially dangerous. These are also known as paraesophageal hernias. Hope this helps!