Ulcerative colitis appears as a diffuse alteration of the colonic mucosa, resulting in varying degrees of inflammation. This inflammation can be variable in its severity and extent of colon involved. Here, the mucosa is diffusely inflamed, obliterating the visualization of the normally evident submucosal vascular pattern, granular appearance of the mucosa, and ulceration of the mucosa.
The subtlest changes of ulcerative colitis may indicate loss or distortion of the submucosal vascular pattern. This can also be a sign of healed colitis, now in remission.
Long standing ulcerative colitis may cause loss of the normally distinct haustral markings, as seen here. While this patient was in clinical remission, the distorted vascular pattern and the loss of normal haustra, causing a “smooth” appearance to the colon, indicate prior chronic inflammation of the colon from colitis.
In some cases of left sided ulcerative colitis, the right side of the colon will appear endoscopically and histologically normal, except for the immediate periappendiceal region, which may have mild or more severe inflammation as seen here. This is referred to as a “cecal red patch.”
In moderately active ulcerative colitis, the mucosa will appear granular, with surface erosions. Minor contact bleeding from the colonoscope may be seen. The submucosal vascular pattern is not seen due to inflammation of the mucosa.
In some instances of severe ulcerative colitis, exudative mucus may coat the wall of the colon. Despite the lack of ulcers, the degree of inflammatory exudate would constitute this as severe colitis.
Patients taking oral mesalamine for control of their colitis may have the medication “shell” evident in their colons at the time of colonoscopy. The shell prevents release of the mesalamine in the small intestine, and allows it to be released in the colon.