核素示踪乳果糖氢呼气试验诊断小肠细菌过度生长

Value of lactulose hydrogen breath test combined with radionuclide imaging in the diagnosis of small intestinal bacterial overgrowth

目的 通过比较核素和钡剂对乳果糖的示踪效果,探讨核素示踪乳果糖氢呼气试验（LHBT）诊断小肠细菌过度生长（SIBO）的方法及应用价值.方法 对2010年11月至2012年11月在浙江大学医学院附属邵逸夫医院消化科门诊确诊为肠易激综合征（IBS）的89例患者[男47例、女42例,年龄（45.7±12.9）岁]及招募的13名健康志愿者[男9名、女4名,年龄（43.3±8.6）岁]进行前瞻性研究.所有受试者均行核素示踪LHBT,记录氢呼气值升高0.005‰（体积分数;下同）时间与核素OCTT.其中有4名健康志愿者1周后再行钡剂示踪LHBT,记录氢呼气值升高0.020‰时钡剂到达的部位.对诊断SIBO阳性IBS患者进行利福昔明治疗,观察治疗效果.对比2种示踪剂的示踪效果,采用χ^2检验、Pearson相关分析和Wilcoxon秩和检验分析数据.结果 （1）4名健康志愿者的氢呼气值升高0.020‰时钡剂均位于小肠内,其中1名延迟摄片钡剂仍未进入结肠;（2）IBS患者和健康志愿者中,单纯LHBT对SIBO的检出率分别为43.8%（39/89）和5/13,差异无统计学意义（χ^2=0.133,P=0.716）;核素示踪LHBT对SIBO的检出率分别为39.3%（35/89）和1/13,差异有统计学意义（χ^2=4.970,P=0.026）.（3）13名健康志愿者氢呼气值升高0.005‰的时间为（73±31） min,与核素OCTT相关[（50±19） min;r=0.871,P〈0.001];89例IBS患者中,SIBO阴性者54例,氢呼气值升高0.005‰的时间为（83±34） min,与核素OCTT相关[（66±28） min;r=0.735,P〈0.001];SIBO阳性者35例,氢呼气值升高0.005‰的时间（36±30） min,与核素OCTT无相关性[（75±30） min;r=0.304,P=0.076].（4）34例SIBO阳性IBS患者利福昔明治疗前腹痛、腹胀频率评分分别为5（4,6）分、4（1,6）分,治疗后分别为4（3,5）分、0（0,4）分,差异均有统计学意义（z值：-4.842和-5.388,均P〈0.001）.结论 单纯的LHBT并不能诊断SIBO,核素示踪LHBT是较理想的SIBO诊断方法.

Objective To compare the tracing effects of radionuclide and barium sulfate on lactulose hydrogen breath test （LHBT）, and to explore the value of LHBT combined with radionuclide imaging in the diagnosis of small intestinal bacterial overgrowth （SIBO） in patients with irritable bowel syndrome （IBS）.Methods From November 2010 to November 2012, 89 patients （47 males, 42 females;mean age （45.7±12.9） years） with IBS and 13 healthy volunteers （9 males, 4 females;mean age （43.3±8.6） years） were enrolled in this prospective study.All the subjects underwent LHBT combined with radionuclide imaging.Recording the time when the increment of H2 value 〉0.005‰ and the OCTT of the radionuclide.Four healthy volunteers also underwent LHBT combined with barium sulfate 1 week after radionuclide imaging.The location of barium sulfate was recorded when H2 value increment 〉0.020‰.Patients with SIBO received rifaximin treatment, and the effect was observed.χ^2 test, Pearson correlation analysis and Wilcoxon rank sum test were used to analyze the data.Results （1）In LHBT combined with barium sulfate test, barium sulfate was found still stagnating in small intestine by abdominal X-ray when H2 value increment 〉0.020‰ in 4 healthy volunteers, and barium sulfate didn′t reach the colon in delayed imaging in 1 patient.（2） The rates of SIBO detected by LHBT in IBS patients and healthy volunteers were significantly different （43.8%（39/89） vs 5/13;χ^2=0.133, P=0.716）, and those detected by LHBT combined with radionuclide imaging were also significantly different （39.3%（35/89） vs 1/13;χ^2=4.970, P=0.026）.（3）The time of H2 value increased 〉0.005‰ correlated well with OCTT in 13 healthy volunteers （（73±31） and （50±19） min;r=0.871, P〈0.001） and 54 IBS patients without SIBO （（83±34） and （66±28） min;r=0.735, P〈0.001）, but there was no correlation in 35 IBS patients with SIBO （（36±30） and （75±30） min;r=0.304, P=0.076）.（4）A total of 34 SIBO-positive patients received a rifaximin treatment, with a significant improvement in the frequency of abdominal pain and abdominal distension after the treatment according to Rome Ⅲ diagnostic criteria： 5（4, 6） vs 4（3, 5）, 4（1, 6） vs 0（0, 4）（z values：-4.842 and-5.388, both P〈0.001）.Conclusion LHBT alone is not a valid test for SIBO, and LHBT combined with radionuclide imaging is a good candidate for SIBO diagnosis.