They do miss things in the scopes, did your GP or specialist recommend having the scope done by someone else? Not every GI or Internist is created equal or equally meticulous in their examination of the bowel.
I do know that mucous and narrow stools in the BM can be caused by inflamation of some sort due to IBS, Crohn's or colitis (although they should have got that on the scope) and in general a bowel obstruction of some kind such as a tumour or benign mass. I've read (on mayoclinic.com) that the Collagenous colitis you mentioned causes the layer of connective tissue (collagen) in the colon to thicken - which obviously explains narrowed stools and mucous.
They mention that you should probably - 1) Eat a low-fat, low-fiber diet. Choose foods that contain less fat and foods that are low in fiber. This may help relieve diarrhea and BM issues. 2) Avoid NSAID pain relievers. If you regularly take over-the-counter pain relievers thought to contribute to collagenous colitis and lymphocytic colitis, your doctor may recommend a different medication.
The other thing is PCS or post cholysystectomy syndrome (ie. issues after having your GB removed). Although, I have read that PCS is only a transitionary diagnosis on the road to actually finding the cause of your issues. I can relate as I had my GB out over a year ago and haven't quite been the same since.
Hope you find some answers.
Thanks for all the infomation. I have been gluten free since the beginning of the year with the exception of the month I started gluten in order to get a more accurate result from my endoscopy. These symptoms have gotten worse since I have started the GF diet as well as the low-fat diet, which I started over a year ago when I had my GB removed..
Celiac disease (gluten intolerance) seems to have a mess of symptoms. My sister inlaw has this. According to the Canadian Celic Association:
Common symptoms are anemia, chronic diarrhea, weight loss, fatigue, cramps and bloating, irritability.
Although some or all of these symptoms occur in celiac disease, some can also occur in many other diseases more common than celiac disease.
In other cases, sufferers from gluten-intolerance develop an intense burning and itching rash called dermatitis herpetiformis. The intestinal symptoms of celiac disease may or may not appear in dermatitis herpetiformis.
They recommend a change in diet -
Celiac disease as yet has no known cure, but can usually be effectively treated and controlled. The treatment of celiac disease is strict adherence to a GLUTEN FREE DIET FOR LIFE. This requires knowledgeable dietetic counselling and frequent "up-dates" as commercial food contents change.
Celiacs must be alert to hidden sources of gluten such as HVP/HPP (hydrolyzed vegetable/plant protein); malt; spelt; kamut; and certain drug products.
Today's processed and packaged foods have many hidden sources of gluten which can be unintentionally ingested. Particular care should be taken in the selection of soups, luncheon meats and sausages.
The person with celiac disease MUST READ THE LIST OF INGREDIENTS ON ALL LABELS, EVERY TIME.
There is a great variation in sensitivity to gluten among those with celiac disease, and although one may have no obvious symptoms, damage to the intestinal lining may still occur.
You didn't mention your diet. Maybe you could try adjusting your diet and see if the symptoms improve. Best of luck.