Nayar M, Rhodes J M
Department of Medicine, University of Liverpool, Liverpool, UK.
Postgrad Med J. 2004 Apr;80(942):206-13. doi: 10.1136/pgmj.2003.013722.
Ulcerative colitis and Crohn's disease result from an interaction between genetic and environmental factors. Only one gene, NOD2/CARD15, has been clearly identified; a minority of people with alteration of this gene develop Crohn's disease. The NOD2/CARD15 protein is thought to be involved in defence against intracellular bacteria. This supports the idea that Crohn's disease and ulcerative colitis result from altered immunological responses to the normal intestinal flora. Life expectancy is normal in ulcerative colitis and nearly so in Crohn's disease, but both conditions cause considerable morbidity. Approximately 80% of patients with Crohn's disease eventually require surgery, and about 25% of patients with ulcerative colitis require colectomy. Treatment of ulcerative colitis is generally by corticosteroids for acute disease and mesalazine for maintenance, but the range of therapies for Crohn's disease is expanding. Alternative therapies include immunosuppressives, enteral nutrition, antibiotics, anti-TNF antibody (infliximab), corticosteroids, and surgery. High dosages of corticosteroids may provide symptomatic relief in Crohn's disease but do not affect the long term natural history of the disease, and management strategies should avoid using steroids whenever possible.
溃疡性结肠炎和克罗恩病是由遗传因素和环境因素相互作用引起的。目前仅明确鉴定出一个基因，即NOD2/CARD15；该基因发生改变的少数人会患克罗恩病。NOD2/CARD15蛋白被认为参与抵御细胞内细菌。这支持了克罗恩病和溃疡性结肠炎是由于对正常肠道菌群的免疫反应改变所致的观点。溃疡性结肠炎患者的预期寿命正常，克罗恩病患者的预期寿命也接近正常，但这两种疾病都会导致相当高的发病率。约80%的克罗恩病患者最终需要手术，约25%的溃疡性结肠炎患者需要进行结肠切除术。溃疡性结肠炎的治疗通常在急性期使用皮质类固醇，维持期使用美沙拉嗪，但克罗恩病的治疗方法范围正在扩大。替代疗法包括免疫抑制剂、肠内营养、抗生素、抗TNF抗体（英夫利昔单抗）、皮质类固醇和手术。高剂量皮质类固醇可能会缓解克罗恩病的症状，但不会影响该病的长期自然病程，管理策略应尽可能避免使用类固醇。
