A retired grandfather's heartburn was the warning sign of a rare illness

For retired grandfather Ed Langevin, life was good. He spent plenty of time with his grandkids. He went to church regularly. And he loved the simple things, like a bowl of pasta or a sub from his favorite deli.

But in February 2024, everything changed. Every meal left Langevin with heartburn. He could barely eat, and even a little bit of food made him feel full. While he used to regularly eat a whole sub, now a quarter of the sandwich left him feeling full and kept him from eating for days. He was often nauseous, and he became afraid of eating because of the pain food caused him. He lost 20 pounds in three months.

"I didn't think I was going to make it, to be honest," Langevin told CBS News. "I just wasn't feeling good at all. I'd be laying out in the sunroom on the couch most of the day