Kanazawa Motoyori, Palsson Olafur S, Thiwan Syed I M, Turner Marsha J, van Tilburg Miranda A L, Gangarosa Lisa M, Chitkara Denesh K, Fukudo Shin, Drossman Douglas A, Whitehead William E
Center for Functional GI and Motility Disorders, University of North Carolina at Chapel Hill, North Carolina, USA.
Am J Gastroenterol. 2008 Oct;103(10):2550-61. doi: 10.1111/j.1572-0241.2008.02066.x. Epub 2008 Aug 5.
Irritable bowel syndrome (IBS) patients show pain hypersensitivity and hypercontractility in response to colonic or rectal distention. Aims were to determine whether predominant bowel habits and IBS symptom severity are related to pain sensitivity, colon motility, or smooth muscle tone.
One hundred twenty-nine patients classified as IBS with diarrhea (IBS-D, N = 44), IBS with constipation (IBS-C, N = 29), mixed IBS (IBS-M, N = 45), and unspecified IBS (IBS-U, N = 11) based on stool consistency, and 30 healthy controls (HC) were studied. A manometric catheter containing a 600-mL capacity plastic bag was positioned in the descending colon. Pain threshold was assessed using a barostat. Motility was assessed for 10 min with the bag minimally inflated (individual operating pressure [IOP]), 10 min at 20 mmHg above the IOP, and for 15-min recovery following bag inflation. Motility was also recorded for 30 min following an 810-kcal meal.
Compared with HC, IBS patients had lower pain thresholds (medians 30 vs 40 mmHg, P < 0.01), but IBS subtypes were not different. IBS symptom severity was correlated with pain thresholds (rho =-0.36, P < 0.001). During distention, the motility index (MI) was significantly higher in IBS compared with HC (909 +/- 73 vs 563 +/- 78, P < 0.01). Average barostat bag volume at baseline was higher (muscle tone lower) in HC compared with IBS-D and IBS-M but not compared with IBS-C. The baseline MI and bag volume differed between IBS-D and IBS-C and correlated with symptoms of abdominal distention and dissatisfaction with bowel movements. Pain thresholds and MI during distention were uncorrelated.
Pain sensitivity and colon motility are independent factors contributing to IBS symptoms. Treatment may need to address both, and to be specific to predominant bowel habit.
肠易激综合征（IBS）患者在结肠或直肠扩张时表现出疼痛超敏反应和高收缩性。本研究旨在确定主要排便习惯和IBS症状严重程度是否与疼痛敏感性、结肠动力或平滑肌张力相关。
根据粪便稠度，将129例患者分为腹泻型肠易激综合征（IBS-D，n = 44）、便秘型肠易激综合征（IBS-C，n = 29）、混合型肠易激综合征（IBS-M，n = 45）和未定型肠易激综合征（IBS-U，n = 11），并纳入30名健康对照者（HC）进行研究。将一个容量为600 mL的塑料袋的测压导管置于降结肠。使用压力控制仪评估疼痛阈值。在塑料袋轻微充气（个体操作压力[IOP]）的情况下评估动力10分钟，在高于IOP 20 mmHg的压力下评估10分钟，并在塑料袋充气后进行15分钟的恢复评估。在摄入810千卡餐后也记录30分钟的动力情况。
与HC相比，IBS患者的疼痛阈值较低（中位数分别为30 mmHg和40 mmHg，P < 0.01），但IBS各亚型之间无差异。IBS症状严重程度与疼痛阈值相关（rho = -0.36，P < 0.001）。在扩张期间，IBS患者的动力指数（MI）显著高于HC（909±73对563±78，P < 0.01）。与IBS-D和IBS-M相比，HC在基线时的压力控制仪平均袋容量更高（肌张力更低），但与IBS-C相比无差异。IBS-D和IBS-C之间的基线MI和袋容量不同，且与腹胀症状和对排便的不满意相关。扩张期间的疼痛阈值和MI不相关。
疼痛敏感性和结肠动力是导致IBS症状的独立因素。治疗可能需要同时针对这两个方面，并且要针对主要排便习惯进行个体化治疗。
