Endoscopic features distinguishing normal from inflamed colonic mucosa
Normal colonic mucosa on colonoscopy shows preserved vascular pattern, smooth mucosal surface, and no friability, erosions, ulcers, or bleeding. [1] Inflamed colonic mucosa shows increased mucosal erythema, decreased or absent vascular pattern, mucosal granularity, friability with contact bleeding, erosions, ulceration, and spontaneous bleeding as severity increases. [1], [2], [3]
Baseline “normal” endoscopic descriptors
- Intact vascular pattern without loss of vessels. [1], [2]
- Smooth mucosal surface with normal light reflex. [3]
- No mucosal erythema. [1], [3]
- No friability. [1]
- No erosions or ulceration. [1]
- No spontaneous bleeding. [1]
Ulcerative colitis endoscopic inflammation signs (Mayo endoscopic subscore components)
The Mayo endoscopic subscore describes inflammation primarily through progressive abnormalities in erythema, vascular pattern, friability, erosions, ulceration, and bleeding. [1]
- MES 0 (normal/quiescent): no friability, no granularity, and intact vascular pattern. [1], [2]
- MES 1 (mild): erythema, decreased vascular pattern, and mild friability. [1], [2]
- MES 2 (moderate): marked erythema, absent vascular pattern, friability, and erosions (may also include pinpoint ulcerations). [1], [2]
- MES 3 (severe): ulceration with spontaneous bleeding. [1], [2]
Endoscopic descriptors used to grade “erythema–vascular–granularity–friability–ulceration–bleeding”
- Erythema reflects active mucosal inflammation and increases with severity. [1], [4]
- Loss of vascular pattern progresses from decreased visibility to complete absence in more severe disease. [1], [2]
- Granularity shifts from absent in normal mucosa to present in mild and more active inflammation. [1], [4]
- Friability indicates mucosal injury that occurs with minimal endoscope contact and correlates with active disease. [1], [4]
- Erosions and ulceration represent mucosal epithelial disruption that appears in moderate-to-severe inflammation. [1], [2]
- Bleeding progresses from contact bleeding to spontaneous bleeding in more severe inflammation. [1], [2]
Key differences versus “normal-appearing” mucosa
- Normal mucosa lacks friability and lacks erosions and ulceration. [1], [2]
- Inflamed mucosa shows friability and may show erosions or ulceration depending on severity. [1], [2]
- Normal mucosa maintains an intact vascular pattern. [1], [2]
- Inflamed mucosa shows decreased or absent vascular pattern. [1], [2]
Crohn’s colitis supportive endoscopic signs of mucosal inflammation (adjunctive)
When Crohn’s disease is part of the differential, inflamed colonic mucosa may show ulcers that can be aphthous, discrete, longitudinal, or associated with cobblestone-type appearance. [4]
- Aphthous and small ulcers indicate inflammatory mucosal disruption. [4]
- Cobblestoning reflects an irregular mucosal surface produced by ulceration and intervening inflamed tissue. [4]
Practical interpretation schema for colonoscopy reports
- Absence of erythema with intact vascular pattern plus no friability and no erosions or ulceration corresponds to normal/quiescent mucosa (MES 0). [1], [2]
- Presence of erythema with decreased vascular pattern and mild friability corresponds to mild inflammation (MES 1). [1], [2]
- Marked erythema with absent vascular pattern plus friability and erosions corresponds to moderate inflammation (MES 2). [1], [2]
- Ulceration with spontaneous bleeding corresponds to severe inflammation (MES 3). [1], [2]
Common pitfalls
- Reported descriptions that omit friability, vascular pattern, and whether ulcers are present reduce the ability to distinguish normal from inflamed mucosa using established endoscopic activity frameworks. [1], [2]
- Inflicted mucosal trauma from instrumentation can mimic contact bleeding, which can be distinguished by the pattern of accompanying erythema, loss of vascular pattern, and erosions/ulceration. [1], [2], [4]
Distinguishing normal from inflamed mucosa in a single sentence
Normal mucosa demonstrates intact vascular pattern and no friability, erosions, ulceration, or bleeding, whereas inflamed mucosa demonstrates progressive erythema, decreased/absent vascular pattern, granularity, friability with contact bleeding, erosions, ulceration, and spontaneous bleeding with increasing severity. [1], [2], [3], [4]