Identification of risk factors for acute pancreatitis from routine radiological investigation of the biliary tract

Biliary Pancreatitis. Liver Function Tests and Common Biliopancreatic Channel Kinetics--Biliopancreatic Reflux

OBJECTIVE

To determine the prevalence of biliopancreatic reflux (BPR) in patients with biliary pancreatitis (BP) undergoing elective cholecystectomy with intraoperative cholangiography (IOC) in comparison with a control group of symptomatic cholelithiasis (CG).

PATIENTS AND METHODS

Retrospective review of 107 consecutive BP cases. BPR was determined by IOC and liver function tests (LFT) were recorded at admission (A), 48hours, and preoperative examination (P). LFT analysis between A and P were analysed between groups with respect to BPR, time interval to cholecystectomy within the same group and by determination of observed value/maximum normal value ratio (OV/MNV).

RESULTS

BPR incidence was 38.3% in BP in comparison with 5% in CG (p=0.0001) it was independent from interval time to cholecystectomy, in contrast with Odditis, suggesting an anatomical condition for CCBP and a functional one for Odditis. LFT analysis showed no differences in relation to BPR incidence. LFT excluding AP and GGT returned to normal values with significant differences in OV/MNV when BPR was present which points to an increased cholestasis in BPR group. US dilatation of CBD was noted in 10.3% and was associated to CCBP.

CONCLUSIONS

BPR in BP increases cholestasis and contributes to confusion in the estimation of common bile duct stones increasing ERCP-EE rates. US and biochemical markers of CBDS show a low specificity due to BPR-CCBP which suggests that MRI-cholangiography is a mandatory exploration before ERCP-EE examination.

Magnetic resonance cholangiopancreatography in the preoperative assessment of patients with biliary pancreatitis

BACKGROUND

The ultimate treatment of acute biliary pancreatitis (ABP) is undoubtedly laparoscopic cholecystectomy, but controversy remains about the optimal imaging method in the preoperative assessment of these patients. In this study, we evaluated the usefulness of magnetic resonance cholangiopancreatography (MRCP) in detecting common bile duct (CBD) stones and associated pathologies in patients with ABP. At the same time, we tried to determine the natural transit time of gallstones from gallbladder to duodenum in ABP.

METHODS

Between February 1999 and October 2006 a prospective observational study was conducted and 104 consecutive patients with ABP were recruited. MRCP findings were correlated with subsequent endoscopic retrograde cholangiopancreatography, endoscopic ultrasonography, intraoperative cholangiography or clinical follow-up.

RESULTS

MRCP correctly predicted the presence of CBD stones in 19 out of 104 patients, and there were two false-positive and four false-negative results. The ability of MRCP to detect CBD stones was: positive predictive value 90.5%, negative predictive value 95.2%, sensitivity 82.6%, specificity 97.5% and overall accuracy 94.2%. MRCP performed within 48 h after admission showed CBD stones in 28.6% of the patients decreasing to 8.0% after 1 week. MRCP disclosed cholecystitis in 25 patients, anatomical variants of the cystic duct in 10 patients and a wide variety of other abnormalities of the upper abdominal cavity.

CONCLUSION

MRCP is highly accurate in the preoperative detection of CBD stones and other biliopancreatic pathologies in patients with gallstone pancreatitis.

Small gallstones are associated with increased risk of acute pancreatitis: potential benefits of prophylactic cholecystectomy?

OBJECTIVES

Pancreatitis is a severe complication of gallstone disease with considerable mortality. Small gallstones may increase the risk of pancreatitis. Our aims were to evaluate potential association of small stones with pancreatitis and potential beneficial effects of prophylactic cholecystectomy.

METHODS

Stone characteristics were determined in patients with biliary pancreatitis (115), obstructive jaundice due to gallstones (103), acute cholecystitis (79), or uncomplicated gallstone disease (231). Sizes and numbers of gallbladder and bile duct stones were determined by ultrasonography and endoscopic retrograde cholangiopancreatography, respectively. Effects of prophylactic cholecystectomy were assessed by decision analyses with a Markov model and Monte Carlo simulations.

RESULTS

Patients with pancreatitis or obstructive jaundice had more and smaller gallbladder stones than those with acute cholecystitis or uncomplicated disease (diameters of smallest stones: 3 +/- 1, 4 +/- 1, 8 +/- 1, and 9 +/- 1 mm, respectively, p < 0.01). Bile duct stones were smaller in case of pancreatitis than in obstructive jaundice (diameters of smallest stones: 4 +/- 1 vs 8 +/- 1, p < 0.01). Multivariate analysis identified old age and small stones as independent risk factors for pancreatitis. Decision analysis in a representative group of patients with small (<or=5 mm) gallstones (5,000 patients, 67% females, 45 yr old, 10-yr follow-up) indicates that life-years may be gained or lost by cholecystectomy, depending on incidence and mortality of pancreatitis.

CONCLUSIONS

Small gallstones are associated with pancreatitis. Prophylactic cholecystectomy may lead to gain or loss of life-years in patients with small stones, depending on incidence and mortality of pancreatitis.

Nonsurgical management of gallstone disease

Cholelithiasis is a common disease in the United States associated with significant morbidity. Surgical treatment with cholecystectomy has been increasing with a significant cost to the health care system. Surgical management is not without risk. Cholecystectomy has also been associated with a significant morbidity and mortality in elderly patients. Cholecystectomies are often performed unnecessarily in gallstone patients for nonspecific symptoms. Many patients with nonspecific pain, which may have a psychogenic component, continue to experience similar pain after cholecystectomy. There are problems in determining the symptom status of patients. Patients who believe surgery will relieve symptoms may maximize their symptoms, whereas patients who are reluctant to undergo surgery may minimize their symptoms. Although cholecystectomy is the mainstay of gallstone treatment, bile acid therapy and, if available, ESWL and topical dissolution are nonsurgical treatment alternatives in selected patients. In selected cases, in particular in the elderly and in other patients at increased risk from surgery, nonsurgical management offers lower morbidity and mortality than does operative treatment. The decision for surgical versus nonsurgical management should be based on both objective selection criteria and patient choice.

Symptoms of gallstone disease

The most certain symptomatic manifestation of gallstones is episodic upper abdominal pain. Characteristically, this pain is severe and located in the epigastrium and/or the right upper quadrant. The onset is relatively abrupt and often awakens the patient from sleep. The pain is steady in intensity, may radiate to the upper back, be associated with nausea and lasts for hours to up to a day. Dyspeptic symptoms of indigestion, belching, bloating, abdominal discomfort, heartburn and specific food intolerance are common in persons with gallstones, but are probably unrelated to the stones themselves and frequently persist after surgery. Many, if not most, persons with gallstones have no history of pain attacks. Persons discovered to have gallstones in the absence of typical symptoms appear to have an annual incidence of biliary pain of 2-5% during the initial years of follow-up, with perhaps a declining rate thereafter. Gallstone-related complications occur at a rate of less than 1% annually. Those whose stones are symptomatic at discovery have a more severe course, with approximately 6-10% suffering recurrent symptoms each year and 2% biliary complications. The far higher rates of symptom development reported in a few studies raise the possibility that these incidence estimates may be too low. The best predictors of future biliary pain are a history of pain at the time of diagnosis, female gender and possibly obesity. The risk of acute cholecystitis appears to be greater in those with large solitary stones, that of biliary pancreatitis in those with multiple small stones, and that of gallbladder cancer in those with large stones of any number. Drugs that inhibit the synthesis of prostaglandins may now be the treatment of choice in patients with gallstones who are suffering acute pain attacks. Persistent dyspeptic symptoms occur frequently following cholecystectomy. A prolonged history of such symptoms prior to surgery and evidence of significant psychological distress appear to be the best predictors of unsatisfactory outcome.

Pancreatic-duct reflux and acute gallstone pancreatitis

A consecutive series of 614 operative cholangiograms was studied prospectively to determine the relationship of pancreatic-duct reflux to a previous history of acute gallstone pancreatitis. Of 53 patients who had previously had pancreatitis, 33 had pancreatic-duct reflux on their cholangiogram (62.3%), whereas, of 561 patients with no history of pancreatic disease, pancreatic-duct reflux was seen in only 82 (14.6%). In patients with a history of pancreatitis, reflux occurred into a wider pancreatic duct, at a greater angle between the bile and pancreatic ducts, and was associated with a longer functioning common channel. The wider cystic duct, wider common bile duct, and multiple small stones seen in patients with previous pancreatitis and pancreatic-duct reflux were suggestive of gallstone migration being associated with reflux. There was no correlation between pancreatic-duct reflux and the presence of choledochal calculi. Two patients developed recurrent severe pancreatitis after pancreatic-duct reflux of infected bile. Patients with gallstone pancreatitis appear to have an increased tendency for pancreatic-duct reflux that is mechanically facilitated by differences in the choledocho-pancreatic duct anatomy.

Effects of bile, infection and pressure on pancreatic duct integrity

Ionic flux, potential difference and mucosal ultrastructure have been studied in the rat bile-pancreatic duct and the effects of pressure, bile and infection on the duct evaluated. The duct remained stable after perfusion with control solution under low pressure and high pressure produced widening of intercellular spaces only. Perfusion with a bacterial solution of Escherichia coli did not effect significant changes. Sterile human bile disturbed the integrity of the duct by increasing ionic flux, altering potential difference and producing reversible ultrastructural changes of cell oedema. High pressure increased these changes. Infected human bile under high or low pressure was by far the most toxic substance tested. Perfusion with infected bile led to irreversible duct damage and complete loss of duct integrity. Pressure and infected bile may have a role in damaging duct integrity and could thus play an integral part in the genesis of acute gallstone pancreatitis.

The biliary tract in patients with acute gallstone pancreatitis

The biliary tract has been prospectively studied in a consecutive series of 769 patients undergoing surgery for gallstones to determine whether differences exist between subjects with and without a history of acute pancreatitis. The incidence of acute gallstone pancreatitis (AGP) was 7.7 per cent and men with gallstones were significantly more likely to develop pancreatic inflammation. Operations on patients with AGP were accompanied by a higher mortality rate which was almost entirely due to the severity of the disease at the time of surgery. The earlier operations were performed after the onset of pancreatitis the more often stones were found in the common bile duct and at the ampulla. Patients with AGP had smaller and more numerous gallbladder stones in association with a wider cystic duct that controls. The common bile duct diameter in patients with AGP was independent of the presence of choledochal calculi implying either previous temporary obstruction to the biliary tree or a dilated duct ab initio. Pancreatic duct reflux was far more commonly observed on the cholangiograms of patients with AGP and in these patients reflux occurred into a wider pancreatic duct, at a greater angle and was associated with a longer functioning common channel. No patient developed recurrent pancreatitis following biliary surgery. These features strongly support the concept of gallstone migration and suggest that patients with gallstones who develop acute pancreatitis have essential differences in their biliary tree which mechanically facilitate migration of calculi.

Gallstone pancreatitis. Local predisposing factors

Local predisposing anatomic and stone factors were studied in 150 patients with gallstones in order to analyze why some patients with cholelithiasis acquire gallstone pancreatitis and others do not. Number and size of gallstones in the gallbladder and common bile duct, presence of pancreatic duct reflux, diameter of the cystic duct, and size of the duodenal orifice and ampulla of Vater were all studied in 75 patients with gallstone pancreatitis (Group I), 75 patients with cholelithiasis (Group II), and by dissections in 50 autopsy specimens. Stones 5 mm or less in diameter were present in 51 (70%) of Group I gallbladders as compared to 30 (41%) of Group II patients (p less than 0.001). Impacted common bile duct stones were found in 21 (29%) of the Group I patients and only four (5%) of the patients in Group II (p less than 0.001). The mean size of the stones that impacted at the ampulla of Vater in the Group I patients were 3.10 mm, whereas in the Group II patients the mean size of the stones was 7.50 mm (p less than 0.001). The Group I cystic ducts were larger (3.80 mm) than the ducts in the Group II patients (2.36 mm) (p less than 0.001). On operative cholangiography, 50 (67%) showed reflux of contrast material into the pancreatic duct compared to only 14 (18%) in the control Group II (p less than 0.001). These data indicate that small gallbladder stones, enlarged cystic ducts, properly sized impacted stones, and a functioning common channel are predisposing local etiologic factors in the development of gallstone pancreatitis.

The early identification of patients with gallstone associated pancreatitis using clinical and biochemical factors only

Early differentiation of gallstone from nongallstone associated acute pancreatitis by imaging methods is often difficult. Timing of surgery in gallstone pancreatitis is controversial, but early surgery requires early demonstration of gallstones. This study assesses the value of easily available clinical and laboratory data in establishing gallstones as the etiology of pancreatitis. In 405 consecutive episodes of acute pancreatitis, data were collected prospectively on 14 clinical and laboratory variables. Gallstones caused 177 episodes and alcohol 135, 93 were due to other or unknown causes. Age, sex, and within 48 hours of admission, serum alkaline phosphatase, aminotransferases, amylase, and bilirubin were all significantly different (all p less than 0.001, chi square) in gallstone and alcohol groups. Multivariate analysis based on five of these variables enabled correct prediction of the presence or absence of gallstones in 50 of a further 56 episodes. This method may help in planning early interventional treatment of gallstone associated acute pancreatitis.