This study investigated the clinical characteristics of PPDC patients treated at our institution and evaluated their severity and treatment. The results demonstrated that most cases of PPDC occurred within two years of surgery and that half of the cases involved recurrence. Although the positive rate of blood culture tests was high, there were no cases of severe PPDC. Furthermore, there were no significant predictive factors for the development of PPDC.
Previous studies have reported that PPDC occurred in 6.7–36.1% of patients [11–17]. The details of PPDC treatment have been reported for 56 cases [12, 15–17]. These studies showed that anastomotic stenosis was present in 16 cases (29%) and that many of them were treated endoscopically. Most cases without anastomotic stenosis were treated with antimicrobial agents. This study investigated the results of examinations for and treatment of PPDC. These results have not been previously described in detail.
Based on the clinical course of PPDC examined during this study, we made the following observations regarding the pathogenesis and optimal treatment of PPDC: first, the pathogenesis of PPDC was discussed in the absence of any suspicious anastomotic stenosis of the hepaticojejunostomy; although the proportion of positive blood culture test results was high, there were no severe cases, and the biliary enzyme values, which were high at the time of onset, improved only with short-term antibiotic treatment. Therefore, it has been speculated that the pathogenesis of PPDC is a temporary increase in biliary pressure caused by the regurgitation of digestive juices.
Stagnation of the flow of digestive juices in the jejunal loop can easily lead to reflux of digestive juices into the IHBD via anastomosis . As preventative measures, the length of the jejunal loop should be reduced to the minimum necessary and Braun’s anastomosis should be performed .
In contrast, impaired bile excretion in the IHBD is considered the pathogenesis for cases with anastomotic stenosis; moreover, this is also considered the pathogenesis for common acute cholangitis. Narrowing of the anastomosis of the hepaticojejunostomy may be accompanied by hepaticolithiasis, which may lead to a condition like common acute cholangitis. In this study, patients with recurrent cholangitis or suspected anastomotic stenosis were subjected to endoscopic examination and treatment that required multiple procedures; however, no severe cases were observed. Anastomotic stenosis may not be relieved by a single treatment; therefore, careful follow-up and the consideration of multiple possible procedures are recommended. Benign bile duct stenosis is the most common type of anastomotic stenosis; however, caution should be exercised in cases of possible malignant anastomotic recurrence.
PPDC severity was classified according to the TG18 severity criteria. There was no significant difference between mild and moderate diseases in terms of the proportion of positive blood culture test results and treatment duration. Classifications of mild PPDC and moderate PPDC according to the TG18 may be equivalent in terms of the treatment and clinical course.
The basis of treatment for PPDC, with or without anastomotic stenosis, is antibiotic administration. In this study, SBT/ABPC was often the first choice of antibacterial agent for PPDC and resulted in no cases of exacerbation. Additionally, SBT/ABPC can generally treat E. coli, which was frequently detected in blood culture samples in this study, and anaerobic bacteria such as Bacteroides fragilis. Therefore, it is conceivable that SBT/ABPC is a reasonable first choice for PPDC. Previous studies have shown that the overuse of SBT/ABPC has increased the resistant strains against SBT/ABPC in some areas; therefore, blood culture tests should be performed before the use of antibiotics to confirm the causative organism and drug sensitivity [10, 19]. For severe cases, we concur with the TG18 regarding the proposed use of metronidazole and clindamycin to treat B. fragilis with cholangitis after hepaticojejunostomy .
In this study, a short course of antimicrobial therapy resulted in clinical improvement even when Gram-negative bacilli, such as E. coli, were detected in blood culture samples. It has been reported that during the treatment of common acute cholangitis with Gram-negative bacilli, the antibiotic administration period could be shortened to less than two weeks, which is the conventional administration period if the source of infection is controlled, and we believe that this applies to the administration period for PPDC .
Regarding the route of administration, most patients in this study were hospitalized and treated with intravenous infusion. The TG18 indicated that oral antimicrobial therapy is also acceptable for common acute cholangitis depending on the patient’s ability of oral consumption . For mild PPDC cases, follow-up with oral antibiotics in an outpatient clinic may be considered.
One limitation of this study was that most of the cases were observed for more than one year but less than two years, which is an insufficient postoperative evaluation period. Additionally, we did not encounter any severe cases of PPDC. Moreover, this was a retrospective study performed at a single institution. To elucidate the pathogenesis of PPDC and establish unique treatment guidelines, we believe it is necessary to develop a draft diagnosis and treatment unique to PPDC and evaluate their validity in prospective studies.