Doctors put Stevens on steroids -- "a nasty drug" that had side effects -- and several other medications, including so-called biologics or TNF inhibitors, drugs that suppress the immune response.
"I had the same result," he said. "I kept feeling horrible and I had daily fevers up to 102, 103, 104, and night sweats. None worked."
Meanwhile, Stevens had four trips to the emergency room, and surgery to repair his fistula and drain the abscess.
"The doctor had never seen anything like it in his whole career," Stevens said.
In February 2011, two years after his diagnosis, Stevens was admitted to Cleveland Clinic weighing just 120 pounds. Doctors were able to spare his rectum, removing nearly all of his six-foot colon.
He had a temporary ileostomy surgery to attach the small intestine to a pouch on the outside of the skin. That was later reversed, and the small intestine was connected directly to the rectum.
"The first week, I gained 11 pounds back," he said, noting there are no dietary restrictions for Crohn's disease. "I would eat entire loaves of bread every day."
But Stevens knows surgery is not a cure. A colonoscopy this spring showed extensive scarring and some reaction in the anus and small bowel. Now, he is on an immunosuppressant called 6MP or mercaptopurine, a medication typically used to treat cancer patients.
Still, Stevens, who once trained for triathlons, said he is getting back into "decent shape."
"All the doctors have said, 'Don't give up; keep working out. Your body needs to be stimulated. Exercise is important.'"
Just this weekend, Stevens took a "dry run," swimming six miles. He admits 24 miles will be a challenge, but said he is grateful for the medical care that has allowed him live more fully.
Stevens remembers when Costedio first took his hand to help him through the medical decisions.
"It was incredible," he told ABCNews.com, choking up.
"To be honest, I was deathly afraid of surgery," he said. "I was stubborn. But my surgeon told me once they took the colon out, I would kick myself I hadn't done it before. She was exactly right."