ROLE OF THE GUT IN THE PATHOPHYSIOLOGY OF EXTRAHEPATIC BILIARY OBSTRUCTION

Background-Gram negative septic events are the commonest source of mor bidity and mortality as a result of surgery in jaundiced patients. The large intestine provides the major source of Gram negative bacteria i n mammals and is implicated in the pathogenesis of systemic endotoxaem ia in obstructive jaundice. Bile salts have an important part in maint aining indigenous microecological homeostasis through their emulsifyin g properties. Aims-The aim was to investigate the effects of biliary o bstruction and isolated external biliary diversion on gastrointestinal structure and caecal bacterial flora in relation to bacterial translo cation. Method-Six groups of adult male Wistar rats were studied (no o peration, sham operated, and bile duct ligated (BDL) for one and three weeks and a choledochovesical fistula (CDVF) for one week). At the en d of the study period plasma was assayed for evidence of endotoxaemia and the animals were tested for bacterial translocation to the mesente ric lymph node complex (MLNC), liver, lungs, and spleen. Quantitative and qualitative bacteriological studies were performed on the caecal c ontents and segments of colon and terminal ileum were washed and prepa red for histological assessment. Results-Bacterial translocation was s ignificantly increased in the BDL1 (68.8%) and BDL3 (60%) groups compa red with the sham1 (6.3%), sham3 (9.1%), No operation (0%), and CDVF1 (16.7%) groups. Although translocation was more pronounced in the BDL1 group, this was almost exclusively to the MLNC compared with the more widespread translocation to other organs in the BDL3 group. The BDL3 group was the only group with significantly raised concentrations of e ndotoxin and anticore glycolipid. The caecal Gram negative aerobic cou nts were significantly increased in the BDL1 and CDVF1 groups compared with all other groups. There was evidence of structural abnormalities in the terminal ileum of rats jaundiced for three weeks, but not in t he other groups. Conclusions-Biliary obstruction for one and three wee ks promotes bacterial translocation although the mechanisms may be dif ferent. Absence of intralumenal bile results in a significant but self limiting increase in the Gram negative aerobic population, which may account for translocation in the early stages of biliary obstruction. As the duration of biliary obstruction increases systemic endotoxaemia is a consistent feature which, combined with factors such as immunolo gical depression and physical disruption of gut barrier function, may promote bacterial translocation perpetuating systemic sepsis.