A 64-year-old male presents the clinic with complaints of passing dark, tarry, stools. He stated the first episode occurred last week, but it was only a small amount after he had eaten a dinner of beets and beef. The episode today was accompanied by nausea, sweating, and weakness. He states he has had some mid epigastric pain for several weeks and has been taking OTC antacids. The most likely diagnosis is upper GI bleed which won’t be confirmed until further endoscopic procedures are performed.

Question:

1.     What are the variables here that contribute to an upper GI bleed?