Hi, eso. Thanks for the info on small bowel obstruction. I'm pretty familiar with that classic presentation. Many of those more severe symptoms I think occur with more of a complete obstruction picture. Fortunately, I don't think I'm there yet.
Also, as many will attest, peri-umbilical pain can sometimes be "referred" and present diffusely throughout the bowel. So, it's often difficult to tell apart from transverse colon ulceration, narrowing, etc. which is in a similar anatomic region. Even most GIs shrug when questioned on large vs. small bowel "partial" obstructive symptoms. It's a difficult diagnosis when the distention and bloating is more vague and diffuse. But, it's definitely worth knowing what the complete picture looks like (as you so well described).
Hey, banangirl. Yes, I think first stop may be colonoscopy or at least a flex sig to see how many the lower bowel narrowing is. Then, right to an upper endoscope or small bowel series to look elsewhere (if the sigmoid/rectum doesn't look "too" narrowed).
I'm hoping I don't here the dreaded "you might also have IBS" line from the GI if he doesn't think the rectal narrowing is responsible for the stomach/small bowel bloating and the stomach/duodenum/ileum, etc. otherwise looks clear (no inflammation, ulcer, bacterial overgrowth, etc.). I'm always hopeful there's more of a definitive diagnosis to help many of us dealing with these more general "bloating" and "distention" issues, especially when they come on fairly suddenly :)