下消化道出血评估

急性下消化道（gastrointestinal，GI）出血的临床表现较广，包括小出血至引起血流动力学不稳定的大出血。下消化道出血的发生率约为上消化道出血的 1/5，每年每 100,000 成人中约有 20-33 例因下消化道出血住院治疗。[1]Longstreth GF. Epidemiology and outcome of patients hospitalized with acute lower gastrointestinal hemorrhage: a population-based study. Am J Gastroenterol. 1997 Mar;92(3):419-24. http://www.ncbi.nlm.nih.gov/pubmed/9068461?tool=bestpractice.com [2]Lanas A, García-Rodríguez LA, Polo-Tomás M, et al. Time trends and impact of upper and lower gastrointestinal bleeding and perforation in clinical practice. Am J Gastroenterol. 2009 Jul;104(7):1633-41. http://www.ncbi.nlm.nih.gov/pubmed/19574968?tool=bestpractice.com 下消化道出血的发生率随着年龄的增长而升高。

在发达国家/地区，导致严重失血的急性下消化道出血的常见原因为结肠憩室病和血管发育不良。需要快速识别和积极复苏有严重出血或显著共病状态的患者。痔和结肠肿瘤可能频繁导致无血流动力学意义的出血。罕见的出血病因包括孤立性直肠溃疡、血管炎和子宫内膜异位症。15% 表现为下消化道出血的患者在检查后发现存在上消化道出血源。[3]Sengupta N, Feuerstein JD, Jairath V, et al. Management of patients with acute lower gastrointestinal bleeding: an updated ACG guideline. Am J Gastroenterol. 2023 Feb 1;118(2):208-31. https://www.doi.org/10.14309/ajg.0000000000002130 http://www.ncbi.nlm.nih.gov/pubmed/36735555?tool=bestpractice.com ​​[4]Laine L, Shah A. Randomized trial of urgent vs. elective colonoscopy in patients hospitalized with lower GI bleeding. Am J Gastroenterol. 2010 Dec;105(12):2636-41; quiz 2642. https://www.doi.org/10.1038/ajg.2010.277 http://www.ncbi.nlm.nih.gov/pubmed/20648004?tool=bestpractice.com ​ 而高达 25％ 的患者无法明确下消化道出血的出血源。[5]Rockey DC. Lower gastrointestinal bleeding. Gastroenterology. 2006 Jan;130(1):165-71. https://www.gastrojournal.org/article/S0016-5085(05)02404-2/fulltext?referrer=https%3A%2F%2Fpubmed.ncbi.nlm.nih.gov%2F http://www.ncbi.nlm.nih.gov/pubmed/16401479?tool=bestpractice.com ​[6]Schmulewitz N, Fisher DA, Rockey DC. Early colonoscopy for acute lower GI bleeding predicts shorter hospital stay: a retrospective study of experience in a single center. Gastrointest Endosc. 2003 Dec;58(6):841-6. http://www.ncbi.nlm.nih.gov/pubmed/14652550?tool=bestpractice.com

结肠镜检查是已排除肛门直肠或上消化道病因患者的主要评估手段。该检查可定位出血源，并且能止血。内镜止血在大多数病例中均能成功止血。

包括计算机体层成像（computed tomography, CT）血管造影、导管血管造影和放射性核素成像在内的影像学检查可能在特定的临床情况下发挥作用。