传染性直肠炎好发于肛门性交者,尤其是免疫功能不全患者。
放射性直肠炎的直肠出血最常见的原因,可在接受骨盆放射治疗时或放射治疗后引起。[2]Williams HR, Vlavianos P, Blake P, et al. The significance of rectal bleeding after pelvic radiotherapy. Aliment Pharmacol Ther. 2005;21:1085-1090.http://www.ncbi.nlm.nih.gov/pubmed/15854169?tool=bestpractice.com前列腺、泌尿系统或者妇科肿瘤接受放射治疗病例中,超过50%的患者出现过直肠少量出血。[3]Dearnaley DP, Khoo VS, Norman AR, et al. Comparison of radiation side-effects of conformal and conventional radiotherapy in prostate cancer: a randomised trial. Lancet. 1999;353:267-72.http://www.ncbi.nlm.nih.gov/pubmed/9929018?tool=bestpractice.com
缺血性直肠炎多因老年患者近期发生过显著的低血压的事件,或进行腹主动脉瘤手术。
乳糜泻,是由于麸质过敏导致的体重减轻,腹泻和吸收不良,研究证实乳糜泻也与直肠炎相关。[4]Breen EG, Coughlan G, Connolly CE, et al. Coeliac proctitis. Scand J Gastroenterol. 1987;22:471-477.http://www.ncbi.nlm.nih.gov/pubmed/3602927?tool=bestpractice.com
口服或使用非甾体类抗炎药栓剂的病人可诱发直肠炎,并能引起伴有疼痛感的直肠溃疡。[5]D'Haens G, Breysem Y, Rutgeerts P, et al. Proctitis and rectal stenosis induced by nonsteroidal antiinflammatory suppositories. J Clin Gastroenterol. 1993;17:207-212.http://www.ncbi.nlm.nih.gov/pubmed/8228081?tool=bestpractice.com
改道性直肠炎,偶尔发生在肠道改道至粪便回流至造瘘口的患者,(如回肠造漏术或结肠造瘘术),随着粪便排泄的恢复改道性直肠炎是可逆的。[6]Glotzer DJ, Glick ME, Goldman H. Proctitis and colitis following diversion of the fecal stream. Gastroenterology. 1981;80:438-441.http://www.ncbi.nlm.nih.gov/pubmed/7450438?tool=bestpractice.com
有意的和无意的造成腐蚀性试剂进入直肠可引起急性直肠炎。[7]da Fonseca J, Brito MJ, Freitas J, et al. Acute colitis caused by caustic products. Am J Gastroenterol. 1998;93:2601-2602.http://www.ncbi.nlm.nih.gov/pubmed/9860441?tool=bestpractice.com
如果以上因素与疾病都没有联系的话,炎症性肠病(溃疡性结肠炎、克罗恩病)是最有可能的诊断。