Acute biliary pancreatitis (ABP) results from migration of gallbladder stone through the cystic duct into the common bile duct (CBD) which causes either transient or persistent obstruction of the pancreatic duct, resulting in subsequent development of pancreatitis. Most gallstones are smaller than 5 mm in diameter[7-9]. Only a small percentage, around 25% of patients presenting with ABP will have retained CBD stones, while the majority of CBD stones will pass spontaneously given their small size[10-12]. Therefore, CBD imaging is necessary to identify those patients with ABP who have persistent CBD stones. Modalities available for investigation include endoscopic ultrasound (EUS), magnetic resonance cholangiopancreatography (MRCP), laparoscopic ultrasound, and intraoperative cholangiography. In clinical practice, the decision to clarify suspicion of CBD stone by imaging or to proceed directly to endoscopic retrograde cholangiopancreatography (ERCP) due to strong suspicion, is based on a combination of clinical, laboratory and ultrasound or computed tomography findings, in addition to diagnostic methods and resources available in each medical center. However, before proceeding to ERCP with its complication rate of about 5%–10% including post-ERCP pancreatitis (PEP), cholangitis, perforation, and hemorrhage[15-17], presence of CBD stone should be ascertained. The American Society of Gastrointestinal Endoscopy (ASGE) has proposed a strategy to assign the risk of CBD stones in patients with symptomatic cholelithiasis based on clinical, laboratory and sonographic parameters. They were divided according to strength of the parameters into “very strong”, “strong” and “moderate” predictors. The proposed strategy advocate proceeding to ERCP in patients with one “very strong” or two “strong” predictors, or performing an investigative procedure in patients with parameters ranked otherwise. A recent study reported that the specificity of the ASGE very strong predictors was 74% and the positive predictive value (PPV) was 64% with more than one-third of patients undergoing diagnostic ERCP. Although no single parameter consistently and strongly predicts the existence of CBD stones, previous studies have shown that combining clinical, laboratory and imaging predictors together improve the diagnostic accuracy of CBD stones[19-21]. In these guidelines, clinical gallstone pancreatitis by itself received moderate strength in predicting CBD stones. However, we believe that this group is not homogeneous and includes a diverse population with different probabilities of suffering from retained CBD stone. Therefore, this probability may be influenced by additional parameters that deserve clarifying in order to offer the appropriate treatment for each patient.
In univariate regression analysis, several predictors of CBD stones in acute biliary pancreatitis were statistically significant (Table (Table2), 2 ), including: Age (OR: 1.048, 95%CI: 1.021-1.076, P = 0.0004), aspartate transaminase (OR: 1.002, 95%CI: 1.001-1.004, P = 0.0015), alkaline phosphatase (OR: 1.005, 95%CI: 1.002-1.008, P = 0.0005), GGT (OR: 1.003, 95%CI: 1.001-1.004, P = 0.0002) and CBD width by US (OR: 1.187, 95%CI: 1.004-1.402, P = 0.0445). On the other hand, total bilirubin shows non-statistically significant difference between the two groups (OR: 1.033, 95%CI: 0.964-1.108, P = 0.35) (Table (Table2). 2 ). In multivariate regression analysis, three parameters were identified to significantly predict CBD stones: Age (OR: 1.062, 95%CI: 1.026-1.097, P = 0.0005), GGT level (OR: 1.003, 95%CI: 1.001-1.004, P = 0.0003) and dilated CBD (OR: 3.685, 95%CI: 1.160-11.711, P = 0.027), with area under the curve of 0.8433 determined by a ROC curve (Figure (Figure1 1 ).
Demographics and laboratory findings
Core tip: Approximately 20%-30% of patients with acute biliary pancreatitis will retain their common bile duct (CBD) stone. Early identification of these patients is critical since stone extraction is mandatory. We performed a single center retrospective study including 154 patients who were followed for simple clinical, laboratory and radiological parameters. We generated a simple diagnostic score including 3 variables (age, gamma-glutamyl transferase level and CBD width by ultrasound) with excellent diagnostic performance and capability of stratifying patients into low or high risk for retained CBD stone.
A third prospective, randomized controlled trial was performed in Poland and published in an abstract form in 1995. This study involved 280 patients managed in the following ways: 75 were subjected to early endoscopic sphinterotomy because they had a stone impacted at the ampulla of Vater; the remaining 205 patients, who had a grossly normal appearing duodenal papilla, were randomized to immediate ES or conservative management. The patient groups were equivalent with respect to predicted severity of their pancreatitis, age and gender. Combining the data from all patients who had early ES, 17% had complications of pancreatitis, compared with 36% of those who were randomized to conservative therapy.
Acute pancreatitis is a potentially fatal disease with an overall mortality of 2 – 7% despite aggressive intervention.[11–14] The outcome of acute pancreatitis is determined by two factors which reflect the severity of the illness: organ failure and pancreatic necrosis. About half of the deaths in patients with acute pancreatitis occur within the first one/two weeks and are mainly attributable to multiple organ dysfunction syndromes. When not treated, the risk of recurrence in gallstone pancreatitis ranges from 32 to 61%.[10,12,13]
Mild pancreatitis can usually be managed conservatively; a few of these patients require urgent ERCP. If there is concern regarding the possibility of a retained CBD stone, ERCP can be performed safely and almost always successfully following laparoscopic cholecystectomy. The timing of cholecystectomy following ERCP for biliary pancreatitis can vary markedly depending on the severity of pancreatitis. Patients with severe pancreatitis and those with ascending cholangitis are likely to benefit from early ERCP and ES to decompress the biliary tree. Cholecystectomy may follow only several weeks after the necrotizing pancreatitis has resolved. The risk of recurrent biliary pancreatitis should be quite low if ES is performed at the time of the ERCP.
According to Chang et al., patients with mild to moderate gallstone pancreatitis without cholangitis, selective postoperative ERCP and CBD stone extraction are associated with a shorter hospital stay, less cost, no increase in combined treatment failure rate, and significant reduction in ERCP use compared with routine preoperative ERCP. However, the study is limited by its small sample size.
Another new technology is endoscopic ultrasonography, which is highly accurate in documenting stones and tumors but is used less often than ERCP. Endoscopic ultrasonography is useful in obese patients and patients with ileus, and can help determine which patients with acute pancreatitis would benefit most from therapeutic ERCP. Endoscopic ultrasonography can assist with endoscopic trans mural cyst and abscess drainage. Endoscopic ultrasonography and MRCP show promise in increasing the range of options available to search for the cause of acute pancreatitis.[50,55]
Several tests can help differentiate biliary pancreatitis from other causes of pancreatitis. Aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase and serum bilirubin are the so-called liver function tests; they should be reviewed before making a confident diagnosis.
ETIOLOGY OF ACUTE PANCREATITIS
This study did confirm, however, that in expert hands, urgent ERCP for selected patients is safe and beneficial.
Fourthly, as the Folsch study was terminated early it lacks the necessary statistical power to conclude that early ERCP with ES is not beneficial in this particular group of patients with gallstone pancreatitis.[71,72]
In 152 patients from 2010 to 2015, preoperative diagnosis, presence of a CBD stone on US, and age ≥ 60 years were associated with persistent CBD stones. Two risk factors alone had a PPV of 88% and the absence of all risk factors had a NPV of 94%. Age < 60 years and the absence of a CBD stone on US were most predictive of non-therapeutic cholangiography.
Patients with gallstone pancreatitis (GP) or choledocholithiasis (CDL) may have common bile duct (CBD) stones that persist until cholangiography. The aim of this study is to evaluate pre-cholangiogram factors that predict persistent CBD stones.
Multiple logistic regression analyses were performed to identify demographic, laboratory, and radiologic predictors of persistent CBD stones and non-therapeutic cholangiography among adults with GP or CDL.
Age, LFTs, and US help predict persistent CBD stones in patients initially presenting with GP or CDL and help minimize non-therapeutic preoperative cholangiography.