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1、ORIGINAL ARTICLELactulose breath test results in patients with persistent abdominal symptoms following Giardia lamblia infectionMETTE H. MORKEN, GUNNAR NYSAETER, ELISABETH A. STRAND, TRYGVE HAUSKEN 43: 141?145(Received 26 June 2007; accepted 6 August 2007)ISSN 0036-5521 print/ISSN 1502-7708 online #
2、 2008 Taylor median age 30 years, range 18?60 years) and 42 controls (4 M, 38 F; median age 27 years, range142M. H. Morken et al.19?54 years). Two pregnant women were excluded from the study. Microscopy of three stool samples from each patient revealed G. lamblia cysts in 23 (29.8%) of the 77 patien
3、ts. In stool samples from the remaining 54 patients (70.1%), cysts were not detected.Customary symptomsThe patients most prominent symptoms were nau- sea, abdominal pain, bloating, anorexia and diar- rhoea. Symptom pattern as well as total symptom scores were similar for the two patients groups. Nin
4、ety-six percent of the Giardia-infected and 94% of the Giardia-cured patients had IBS according to Rome II criteria, and both patient groups had significantly higher total symptom scores than the normal population (Figure 1, pB0.0001), among whom 26% had IBS according to Rome II criteria.Post-LBT sy
5、mptomsAlso for post-LBT symptoms, symptom patterns as well as total symptom scores were similar for the two patient groups, and both groups had significantly higher total symptom scores after lactulose challenge than the normal population (Figure 2, pB0.001). Fifty-four (70%) of the 77 patients clai
6、med that the types of symptoms provoked by lactulose challenge were similar to those of their customary symptoms.Breath hydrogen excretionThe three groups of subjects had similar breath hydrogen excretion curves (Figure 3). There were no significantdifferencesbetweenmeanvaluesat any time-point. The
7、number of early positive tests (B90 min) and AUCs were also similar for the threegroups (Table I). However, the Giardia-infected persons had significantly more positive LBTs within 180 min (92%) than both the Giardia-negatives (65%, p?0.02) and the normal population (69%, p?0.04)(TableI).Therewereno
8、significant correlations between symptom scores and hydrogen production. This was true for individual symptoms as well as for total symptom scores. In Figure 4 we show the lack of correlation between AUC for breath hydrogen and total post-LBT symptom scores or early and long-lasting symptoms in Giar
9、dia-cured patients.DiscussionIt is now well established that IBS may appear as a sequelofgastrointestinalinfections14.Why symptoms in some patients persist for months to years after clearance of the infection is not known. Patients with abdominal symptoms persisting after01020304050Giardia infectedG
10、iardia curedNormal populationabc Pab=0.50 Pac0.0001 Pbc0.0001Symptom scoresFigure 1. Customary symptom scores in Giardia-infected (n?23) and Giardia-cured patients (n?54) and the normal population (n?42).01020304050Giardia infectedGiardia curedNormal populationabcPab=0.09 Pac=0.029 Pbc0.0001Post LBT
11、- symptom scoresFigure 2. Post-lactulose breath test symptom scores in Giardia- infected (n?23) and Giardia-cured patients (n?54) and the normal population (n?42).0306090120150180010203040506070Giardia infectedGiardia curedNormal populationTime (min)Breath hydrogen (ppm)Figure 3. Breath hydrogen exc
12、retion after lactulose ingestion in Giardia-infected (n?23) and Giardia-cured patients (n?54) and the normal population (n?42).Lactulose challenge in post-infectious IBS143clearance of G. lamblia infection may constitute such a post-infectious IBS condition. Small intestinal bacterial overgrowth is
13、a condition whereby colonic bacteria expand to include the small intestine 8. The term bacterial overgrowth syn- drome has been used to define bacterial overgrowth leading to clinical symptoms, without reference to the pathogenesis of the disorder 15. Lactulose is a semisynthetic disaccharide unavai
14、lable for human digestion due to lack of naturally occurring appro- priate intestinal enzymes 16. However, intestinal bacteriaareabletobreakdownlactulosebyanaerobic fermentation and produce hydrogen and methane as metabolic products. These gases diffuse in the body and appear in exhaled air. Abnorma
15、l amounts of exhaled hydrogen following lactulose challenge may indicate bacterial overgrowth 8, which has been related to the pathogenesis of IBS 9. The relief of symptoms and normalization of the test results through antibiotics argue the case for bacterial over- growth as a cause of IBS 17. There
16、 is, however, considerable controversy about the criteria to be used fordiagnosingbacterialovergrowthbyLBT 7,18,19. Initial guidelines state that two clearly identifiable hydrogen peaks, with an easily detected early peak, are required for a positive test 20. Because this assessment is difficult and subjective,we also applied other commonly used criteria (hydro- gen rise ?20 ppm within 90 min or within 180 min after lactulose) 21 and found very high rates of pos
