Hi Claire,
So on a sigmoid you had UC dx? However, on a subsequent colonoscopy it showed no signs? Also blood tests are among the least reliable. Before I give my opinion, I would say this......Learn to take some emotion out of your thoughts( which is easier said than done ). I say this out of knowing human emotion, but also as someone who would have gladly took that advise if presented a long time ago. I also say this because the last thing you want is anxiety....which btw serotonin 80% of it is located in the Digestive system. I say anxiety because it looks like your typing with angst, and having stress( un needed ) is not the greatest in achieving satisfactory results, in any situation. I could be wrong, but based on your time line and questions you ask, understandingly so, there seems to be anxiety( your worry of a clear test 4 years later ). So, that would be my first advise, is just create less stress. I have a Type A personality so I get it.
To answer your first question. A sigmoidoscopy as you know covers the starting point of the colon. I am sure biopsies were taken of that. I am also sure, in doing so, that it rendered consideration in that dx. However to answer your question, Yes that can be good enough for a Dx, for the mentioned above, but also just in general. Most people who get UC, it starts out in the rectum/sigmoid, or usually is the main area of UC just in gernal( see pancolitis as a difference ). However, a sigmoid is not entirely ideal, because you are limiting the scope of view( literally and figuratively ).
So Ideally, a colonoscopy would be the one. However, that would not disregard the sigmoid in totality. To your second question, is it possible? Yes, anything is possible.....but this kind of goes back to how I opened....less anxiety. The matter of the fact, based on what you wrote, is that there was a DX and suggestion of UC. This I would think would come from the eye but also Biopsy. Also, you mentioned no symptoms at the time, but are noticing discomfort and some minor strange things since then. Basically your histology complaints were no tiredness, but now you are having bits of that. However, lets actually not confuse the two...." Since Diagnosis" and...something happening for years are two different answers. A Diagnosis doesn't really change symptoms....unless the symptoms or problem is treated. An example....I was driving on a road, I was making a turn and got hit by a car. Upon examination there was a chipped vertabrae. This was of concern to the supervisory nurse. I was then sent to a more proper hospital with a surgical team. I was told, I may never walk again. My neck was in a fixed position with a brace. The surgical team was delayed( emergency ). So for 4 hours I could lay there or I could see if I could stand. - I am not advocating this, but the story serves a purpose- Either way, unless I do further damage, nothing I do will change the fact if I can walk or not. So I stood up, got on my feet, and I was fine. I then laid back down, as to not cause anything further. The specialist/surgeon comes in, and says my back did show damage to the vertabrae, but it could be from an old injury...( I weight train ). Also, there is nothing he would do different anyway, regardless of what caused the vertabrae damage, so no surgery( too young, and would not improve outcome ). He asked if I had back pain....I thought about it, and said yes. Now had I given it that much thought prior to the accident...my answer still could have been yes. Do you see what I am getting at? So "Since" the accident I have back pain and a chipped vertabrae, right or wrong?.....Do you see my point? He( surgeon) also correlated that based on what the supervisory nurse said, he thought it was going to be much greater.
So far as since your diagnosis, what else changed, besides your anxiety etc? The diagnosis itself, someone saying something, does not change it's effects on the body, unless treated or solved. Since at the time you had no sympstoms on your histological complaints, what changed...anxiety level? Sleep? ..... Far as your exhaustion etc. The one thing that has changed in the last 4 years is age, maybe you might want to get a blood panel, also hormone panel if rendered.( On your pit. gland, you have a posterior and anterior. They have hormones, LH, FSH, etc ).
I really don't think your grasping for straws, I think you might have some anxiety and are looking for answers. Normal. The fact is, relax. You have a good scope. UC 10% that get it, they will never get it again. In others, it can come and go. Also genetics, if you have someone in your close family, this could some ties to it. However, those are the facts. Maybe it was that...However, stress( an abundant or chronic unnecessary stress is never good ). So, relax...just a little. Which is why I said, have thought with less emotion at times. I am not degrading your curiosity or search of a second or third opinion. However, claire I hope that this helped answer some of your questions. Also, yes most drugs of anti inflammation can have side effects. In fact, Some steroids will give some of what you mentioned. I am actually taking MicroBiology and just covered topic, and can search and see what some of the bacterium were that cause Diarrhea, which your not having. If you ever want to to talk, I can send my info( social media ), and you can feel free to send a message online.