Wald Arnold
Division of Gastroenterology, Hepatology, and Nutrition, University of Pittsburgh Medical Center, 200 Lothrop Street, Pittsburgh, PA 15213, USA.
Curr Treat Options Gastroenterol. 2001 Aug;4(4):293-297. doi: 10.1007/s11938-001-0054-y.
The diagnosis of outlet dysfunction constipation in patients with idiopathic constipation that responds poorly or not at all to conservative measures, such as fiber supplements, fluids, and stimulant laxatives, is based upon diagnostic testing. These tests include colonic transit of radio-opaque markers, anorectal manometry or electromyography, barium defecography, and expulsion of a water-filled balloon. The literature suggests that conditions such as pelvic floor dyssynergia exist but may be over-diagnosed as a laboratory artifact. In our laboratory, we screen patients with balloon expulsion studies, and then test for dyssynergia only if the result of the balloon expulsion test is abnormal. In my opinion, anal sphincter electromyogram and manometry are equivalent in establishing the diagnosis. Barium defecography is helpful in making a diagnosis of a rectocele, but I prefer to document that vaginal pressure on the rectocele significantly improves rectal evacuation. Manometry also helps to establish the presence of megarectum, hypotonia, and weak expulsion efforts. Conceptually, biofeedback training, which incorporates simulated defecation, is the most logical approach to pelvic floor dyssynergia. It incurs no risk and benefits 60% to 80% of patients. The drawbacks are the time-intensive nature of the therapy and the short-term costs, which are offset if there is sustained benefit. There is no evidence that biofeedback is helpful in children with constipation. Habit training has established benefits, but recurrences are frequent and long-term reinforcement is helpful to maintain success. Laxatives and enemas are adjunctive therapies in both habit training and biofeedback. Surgery is effective in those uncommon patients with physiologically significant rectoceles, but surgical division of the puborectalis muscle is risky and unproven. Likewise, botulinum toxin injection into the puborectalis is unproven, but the effects are rarely permanent should incontinence occur. Diagnostic measures and therapeutic success are enhanced when patients are seen in centers experienced with the evaluation of these disorders.
对于特发性便秘且对保守治疗措施（如补充膳食纤维、增加液体摄入及使用刺激性泻药）反应不佳或完全无反应的患者，出口功能障碍型便秘的诊断基于诊断性检查。这些检查包括不透X线标志物的结肠运输试验、肛门直肠测压或肌电图检查、钡剂排粪造影以及水囊排出试验。文献表明，诸如盆底协同失调等情况确实存在，但可能因实验室假象而被过度诊断。在我们实验室，我们先通过水囊排出试验筛查患者，只有当水囊排出试验结果异常时才进行协同失调检测。在我看来，肛门括约肌肌电图和测压在确诊方面效果相当。钡剂排粪造影有助于诊断直肠膨出，但我更倾向于记录阴道对直肠膨出的压力能显著改善直肠排空情况。测压也有助于确定是否存在巨直肠、低张力以及排便动力不足。从概念上讲，结合模拟排便的生物反馈训练是治疗盆底协同失调最合理的方法。它没有风险，60%至80%的患者能从中受益。缺点是治疗耗时且成本较高，如果能持续受益则可抵消这些缺点。没有证据表明生物反馈对便秘儿童有帮助。习惯训练已证实有效果，但复发频繁，长期强化有助于维持成功。泻药和灌肠剂在习惯训练和生物反馈中都是辅助治疗方法。手术对那些直肠膨出具有生理意义的罕见患者有效，但耻骨直肠肌切断术风险大且未经证实。同样，向耻骨直肠肌注射肉毒杆菌毒素也未经证实，而且如果出现失禁，效果很少是永久性的。当患者在有这些疾病评估经验的中心就诊时，诊断措施和治疗成功率会提高。
