Drewes Asbjørn Mohr, Frøkjaer Jens Brøndum, Larsen Ejnar, Reddy Hariprasad, Arendt-Nielsen Lars, Gregersen Hans
Center for Visceral Biomechanics and Pain, Department of Gastroenterology, Aalborg University, Denmark.
Inflamm Bowel Dis. 2006 Apr;12(4):294-303. doi: 10.1097/01.MIB.0000209365.09189.04.
The pain, urgency, and incontinence in ulcerative colitis may be related to changes in viscoelastic properties of the gut wall or to alterations of the sensory pathways. In the present study, we used an advanced rectal probe to study the mechanosensory and smooth muscle properties in patients with active disease.
Nine patients with ulcerative colitis (mean age 39.5 years) with exacerbation limited to the rectum and sigmoid colon and 17 age-matched healthy subjects were included. The rectum was distended before and after pharmacological relaxation of the smooth muscle until moderate pain was reported, and the cross-sectional area, volume, pressure, tension, and strain were computed. To investigate central integration of a tonic stimulus, the bag was finally distended to the pain threshold; then, the cross-sectional area was held constant for 2 min.
The patients were hypersensitive to mechanical stimuli as assessed by the cross-sectional area (F = 21.7; P < 0.001). There were no differences in compliance or stiffness between the 2 groups, but the hypersensitivity was abolished after muscle relaxation. Together with the muscle analysis, this finding demonstrated that the smooth muscles were tonically contracted in the inflamed rectum, resulting in a decreased rectal circumference. The tonic distensions did not evoke central integration of the pain response, indicating that hyperalgesia is more likely related to peripheral factors.
Patients with active ulcerative colitis have hypersensitivity and increased tone of the smooth muscles, which may explain the symptoms. Drugs that affect smooth muscle contraction may be helpful in difficult cases.
溃疡性结肠炎中的疼痛、尿急和失禁可能与肠壁粘弹性特性的改变或感觉通路的改变有关。在本研究中，我们使用先进的直肠探头来研究活动性疾病患者的机械感觉和平滑肌特性。
纳入9例溃疡性结肠炎患者（平均年龄39.5岁），病情加重仅限于直肠和乙状结肠，以及17名年龄匹配的健康受试者。在平滑肌药物松弛前后对直肠进行扩张，直至报告中度疼痛，并计算横截面积、体积、压力、张力和应变。为了研究持续性刺激的中枢整合，最后将气囊扩张至疼痛阈值；然后，将横截面积保持恒定2分钟。
通过横截面积评估，患者对机械刺激高度敏感（F = 21.7；P < 0.001）。两组之间的顺应性或硬度没有差异，但肌肉松弛后超敏反应消失。结合肌肉分析，这一发现表明炎症直肠中的平滑肌持续性收缩，导致直肠周长减小。持续性扩张并未引起疼痛反应的中枢整合，表明痛觉过敏更可能与外周因素有关。
活动性溃疡性结肠炎患者存在超敏反应和平滑肌张力增加，这可能解释了症状。影响平滑肌收缩的药物可能对难治性病例有帮助。
