I've experienced this twice, once 8 years ago and most recently this week. It starts with very painful spasms of the stomach. It feels as though my stomach is being twisted, like when you squeeze out a wet dish cloth. The pain started light, rose to a peak, and then slowly declined. This went on for about 3 hours.
It also felt as if I had a blockage in my small intestine, which was also spasming. I took phenergan which let me sleep. When I woke up the spasms were less. The next morning my stomach was tender to touch. A few hours later, I had severe diarrhea lasted several hours. Now, 3 days later, I feeling much better but still have a tender stomach. I'm eating liquid/soft foods. Everyday it gets better. Can this be from MS?