医学双语 · 溃疡性结肠炎 Ulcerative Colitis

【翻译】Jim 【校对】ivlvn

炎症性肠病是发生在小肠和大肠的炎症反应, 换言之,肠道的炎症反应。 结肠炎特指发生在结肠或大肠的炎症反应。 溃疡性结肠炎是炎症性肠病的其中一种类型, 其主要表现为沿着大肠内面或管腔形成的溃疡,这里所说的大肠包括结肠和直肠。

Inflammatory bowel disease can cause inflammation in the small and large intestine,  in other words...inflammation of the bowel. Colitis refers specifically to inflammation in the colon, or the large intestine. Ulcerative colitis is a type of inflammatory bowel disease that tends to form ulcers along the inner-surface or lumen of the large intestine,  including both the colon and the rectum.

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本文配图 © Osmosis

这些溃疡是发生在粘膜上的斑块缺损。受损粘膜组织发生脱落,进而在粘膜表面残留开放的疮疡或裂口。有时候会发生炎症活动,也就是说新病损的形成。 而当组织开始修复时,病程则进入缓解期。 事实上,最常见的炎症性肠病类型不是别的,正是溃疡性肠病。 但溃疡性结肠炎 只在大肠粘膜和粘膜下层产生炎症和溃疡, 这正是区别于另外一种炎症性肠病--克罗恩病的重点。

These ulcers are spots in the mucosa where the tissue has eroded away and left behind open sores or breaks in the membrane. Sometimes there is a flare which means that new damage has occurred,  and then there are periods of remission when the tissue starts to heal up.  Ulcerative colitis is actually the most common type of inflammatory bowel disease, not that there are that many, but this one causes inflammation and ulcers in the mucosa and submucosa of the large intestine only, which is an important point that sets it apart from Crohn disease, another inflammatory bowel disease.

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虽然学界曾经将肠道溃疡的形成归咎于饮食、压力等某些环境因素,但目前认为这些因素是次要的,即环境因素似乎是让病情加重,而归根到底,如今的学界认为溃疡性结肠炎的发病与自身免疫相关。 实际上,来自免疫系统的细胞毒性T细胞经常出现在病变大肠的上皮组织中。

Now although certain environmental factors like diet and stress were once thought to be the culprit behind these ulcers forming in the gut, now it’s thought that these are more secondary, meaning they seem to make symptoms worse, but ulcerative colitis is now ultimately thought to be autoimmune in origin. In fact, cytotoxic T cells from the immune system are often found in the epithelium lining the colon, 

因此学界认为,炎症和溃疡的形成由T细胞介导。 T细胞通过破坏上皮组织, 进而形成腐蚀缺损区域或溃疡。 但T细胞确切的靶标仍不清楚。

so the thought is that inflammation and ulceration in the large intestine is caused by T cells destroying the cells lining the walls of the large intestine, leaving behind these eroded areas or ulcers. It’s unclear what exactly these T cells are meant to be targeting though.

一些患者的循环血中存在p-ANCA,即核周型抗中性粒细胞胞浆抗体, 这些抗体能靶向攻击自体的中性粒细胞。 虽然发病机理尚未完全明晰, 某些学说提出,其发病在一定程度上归因于针对肠道菌群的免疫反应; 这些肠道菌群在结构上与自身细胞有某些相似, 进而使针对肠道菌群的抗体即p-ANCA交叉作用于自身中性粒细胞。

Some patients have p-ANCA's in their blood, or perinuclear antineutrophilic cytoplasmic antibodies which are kind of antibodies that target antigens in the body's own neutrophils. Although not completely understood,  some theories suggest this might be partly due to an immune reaction to gut bacteria that have some structural similarity to our own cells,  allowing antibodies to those gut bacteria, or p-ANCA's, to cross react with neutrophils.

患者肠道内的产硫菌比例较正常人高, 而肠道内硫化物产量的高低通常与炎症的活动期长短相关,但与缓解期无关。

Patients also seem to have a higher proportion of gut bacteria that produce sulfides, and often high sulfide production is correlated with periods of active inflammation as opposed to remission.

那么,这些基本上是最相关的研究和学说了。实际上,我们还不能明确粘膜损伤具体的机制。

Ultimately though, these are most correlations and theories, right? And we've yet to nail down the precise mechanisms behind mucosal destruction.

因为从根本上说,溃疡性结肠炎的发生是多种环境刺激因素共同作用的结果, 如产硫菌和遗传易感性的共同作用。 因为有溃疡性结肠炎家族史的患者较正常人更易发病。 这种疾病似乎在13到30岁的年轻女性中更为常见, 在高加索人和东欧犹太人中则有更高的患病率。

Because it is ultimately some combination of environmental stimuli,  perhaps the sulfide producing bacteria, mixed with genetic predisposition. Because patients with a family history of ulcerative colitis are more likely to develop the disease themselves. It also seems to be more common in young women, from the teens to the thirties, with more prevalence among Caucasians and eastern European jews.

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溃疡性结肠炎的病灶呈环形和连续性分布。 也就说:炎症在肠腔内弥漫性分布, 从直肠开始向结肠方向蔓延, 没有由正常或未受累组织所引起的明显间隔。 就像从肠道的一端向另一端不断扩展一样。

With ulcerative colitis the pattern for ulceration seems to be circumferential and continuous,  meaning that the inflammation goes around the hole lumen and starts in the rectum, and continues along the large intestine without any apparent breaks of normal, or unaffected, tissue. Like it is working from one end to the other.

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随着组织损伤加重,患者会感到左下腹疼痛, 这个位置对应的是腹腔内的直肠。 随着腹泻程度的加重和频率的增加,有时还会出现便血的现象。

As more damage is done to the tissue, patients experience pain in the left lower quadrant, which corresponds to the rectum. And more severe and frequent bouts of diarrhea, sometimes with blood in the stool as well.

因为粘膜和上皮组织受到了破坏,血液或血浆可以流入肠腔当中, 进而导致肉眼可见的血便。 此外,大肠的其中一个重要功能是什么?是吸收水分,对吧? 基于粘膜上皮细胞受到了破坏,大肠无法有效地履行职能, 导致过多的水分流过肠腔,最终引起腹泻。

As the mucosa and epithelium are destroyed, blood and serum may be released into the lumen, which contributes to blood seen on the stools. But also, what is one of the main jobs of the large intestine? It is absorbing water, right? As these cells are destroyed the large intestine can't perform this function as efficiently, and ends up letting too much water through contributing to diarrhea.

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溃疡性结肠的治疗手段取决于其症状的严重程度。 常用药物有柳氮磺吡啶、氨基水杨酸等抗炎药物。 在某些更严重的病例中,可能会用到免疫抑制药物, 如糖皮质激素、硫唑嘌呤和环孢素。

Treatment for ulcerative colitis depends on the severity of the symptoms. Often anti-inflammatory medications are given, like sulfasalazine or mesalamine. In more severe cases though, drugs that suppress the immune system, like corticosteroids, azathioprine, or cyclosporine might be prescribed.

最后,如果上述这些治疗手段无效,有时候患者将进行结肠切除术, 即结肠的外科手术切除。 因为这种疾病只累及直肠, 因此直肠的切除在一般情况下能达到治愈的效果。 但你必须在手术前衡量治愈该疾病和完全丧失直肠功能的利弊得失。

Finally, if these treatment options fail, sometimes the patient will have a colectomy,  which is a surgical removal of the colon. Since the disease only affects the large intestine,  removal of the colon generally cures the disease, but you have to weight the benefits of curing the disease against the total loss of the large intestine.

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