A Step Forward in the Understanding of Structural and Functional Bowel Damage in Patients with Ulcerative Colitis

摘要

The concept that chronically undertreated inflammationcan progress to irreversible bowel damage (stricturesand fistulae leading to surgery) is currently well acceptedin Crohn disease (CD) and has resulted in a therapeuticparadigm shift towards earlier and more aggressive therapiesin order to prevent disease progression [1]. It is,however, unknown whether ulcerative colitis (UC) presentsthe same tendency to progress to irreversible boweldamage or which factors could be associated with thisprogression. Being a “solely” mucosal disease, UC is nottypically accompanied by the stricturing and fistulizingcomplications seen in CD, and there is an intuitive tendencyamong physicians to consider it a less aggressive ordestructive disease as compared to CD [2]. Need for hospitalization and surgery, or development of dysplasia, arethe usual complications of UC. However, long-lastingUC, where recurrent bouts of inflammation are allowedto progress, can potentially have devastating consequencesin colonic and rectal physiology, as supported by someevidence [3]. For example, it is well known that chronicUC can be complicated by benign strictures and colonshortening and narrowing, with nefarious consequenceson colonic motility [4]. Additionally, fibrosis has alsobeen reported to exist in UC, and benign strictures, althoughless common than in CD, are also a possible complicationof the disease [5]. Additional complications ofthe disease that could be considered as progression aredisease-proximal extension (disease progressing fromproctitis or left-sided colitis to more extensive forms ofinflammation) and pseudopolyps [3]. Finally, one of thelargely unexplored consequences of chronic UC relates toits potential to affect anorectal and colonic function. Severerectal inflammation, not adequately and timely treated,can result in rectal narrowing and presacral space widening,with impairment in rectal compliance, resulting indistressful complaints of fecal incontinence, urgency, andtenesmus [6]. Likewise, many studies, mostly performedin the past, have shown that UC is characterized by decreasedcontractility and a reduction in the pressure oramplitude of segmental contractions, which has been hypothesizedto be a consequence of wall stiffness [7]. The functional consequences of these manometric changesare not well clarified and could partly explain the fact thateven patients with mucosal healing may maintain symptomsof altered stool frequency and consistency [8].