Acute pancreatitis can range from a mild, self-limiting disease that requires no more than supportive care to severe disease with life-threatening complications. Therefore, to provide a framework for clinicians to manage acute pancreatitis and to improve national health care, the Korean Pancreatobiliary Association (KPBA) established the first Korean guideline for the management of acute pancreatitis in 2013. However, many challenging issues exist, which sometimes lead to differences in practice between clinicians. Taking together the recent dramatic changes of latest knowledge and evidence newly obtained, the committee of the KPBA decided to perform an extensive revision of the guidelines. These revised guidelines were developed by using mainly Delphi methods, and the main topics of these guidelines fall under the following topics: 1) diagnosis, 2) severity assessment, 3) initial treatment, nutritional support, and convalescent treatment, 4) the treatment of local complication and necrotizing pancreatitis. The specific recommendations are presented with the quality of evidence and classification of recommendations.

There is general acceptance that a diagnosis of acute pancreatitis requires two of the following three features: 1) epigastric or upper abdominal pain characteristic of acute pancreatitis, 2) serum amylase and/or lipase ≥3 times the upper limit of normal, and 3) characteristic findings of acute pancreatitis on abdominal images such as ultrasonography, computed tomography (CT) or magnetic resonance imaging. Other pancreatic diseases and acute abdomen have been ruled out before making a diagnosis of acute pancreatitis. Serum lipase may be more useful than serum amylase because serum lipase is thought to be more sensitive and specific than serum amylase in the diagnosis of acute pancreatitis. Contrast-enhanced CT scan is the best imaging technique to rule out the conditions that masquerade as acute pancreatitis, to diagnose the severity of acute pancreatitis, and to identify complications of pancreatitis. The etiology of acute pancreatitis should be made clear as soon as possible to decide treatment policy of acute pancreatitis or to prevent the recurrence of pancreatitis. The etiology of acute pancreatitis in an emergency situation should be assessed by clinical history, laboratory tests such as serum liver function tests, measurement of serum calcium and serum triglycerides and ultrasonography. A differentiation of gallstoneinduced acute pancreatitis should be given top priority in its etiologic diagnosis because early endoscopic retrograde cholangiopancreatography should be considered if a complication of cholangitis and a prolonged passage disorder of the biliary tract are suspected.

The severity of acute pancreatitis (AP) is classified into mild, moderately severe, and severe, considering the presence and duration of organ failure and local complications. Since patients with AP show a large difference in mortality and morbidity according to AP severity, evaluation of the severity of patients with AP in the early stage is important for predicting the prognosis and determining treatment plans including transfer to the intensive care unit or advanced facilities. In order to evaluate the initial severity of AP, it is necessary to confirm the presence of organ failure and objective evaluation using imaging or clinical examinations. In this guideline, it is recommended that evaluation using various severity indices such as bedside index for severity in acute pancreatitis (BISAP), systemic inflammatory response syndrome (SIRS), and acute physiology and chronic health evaluation (APACHE)-II scores be considered.

Initial and convalescent treatment of acute pancreatitis (AP) is important in order to improve the prognosis and prevent the recurrence in the patients with AP. Initial intensive treatment includes fluid therapy, pain control, antimicrobial therapy, endoscopic retrograde cholangiopancreatography (ERCP), and nutritional support. Goal-directed therapy is recommended for fluid therapy, and the routine use of prophylactic antibiotics is not recommended. In acute gallstone pancreatitis, urgent ERCP should be performed only in patients with cholangitis or persistent cholestasis. Early oral feeding is advisable as tolerated and enteral feeding via nasogastric or nasojejunal tube appear comparable. In convalescent treatment, cholecystectomy during the initial admission is advisable for mild biliary pancreatitis with gallstone as possible, and treatment against alcohol dependence is considerable for recurrent acute alcoholic pancreatitis. In this review, we recommend practice guidelines for initial treatment, nutritional support, and convalescent treatment.

In severe acute pancreatitis, accompanied by local complications such as acute peripancreatic fluid collection, pancreatic pseudocyst, acute necrotic collection and walled-off necrosis, the mortality rate is as high as 12-25%. In many cases, interventional procedure or surgical treatment are required at an appropriate time. Conservative treatment is considered for acute peripancreatic fluid collection. Endoscopic drainage could be considered preferentially for the treatment of pancreatic pseudocysts with clinical symptoms or complications. In the case of necrotizing pancreatitis, conservative treatment is preferred, but therapeutic intervention should be considered if infectious pancreatic necrosis with clinical deterioration is suspected. For therapeutic intervention, it is recommended to proceed with a step-up approach in which drainage is first performed and, if necessary, necrosectomy is performed. The optimal timing of intervention is considered 4 weeks after the onset of pancreatitis when necrosis become walled-off, but early drainage within 4 weeks can be considered depending on the patient's condition. This guideline provides an overview of current treatment strategies for local complications of acute pancreatitis.

Biliary tract cancer (BTC) are highly aggressive and fatal malignancies. As one of the leading cause of death in Republic of Korea, BTC amoung various malignancies has been one of major public health concerns in the country. Although BTCs, including intrahepatic, perihilar, and distal cholangiocarcinoma, are relatively low-incidence malignancies compared to other cancer, but they represent a major health problem in endemic areas like Korea and Asia contries; moreover, the incidence of intrahepatic cholangiocarcinoma is rising globally. Surgery is the only curative treatment. The optimal surgical approach depends on the anatomical site of the primary tumour, and the best outcomes are achieved through management by specialist multidisciplinary team. Unfortunately, most patients present with locally advanced or metastatic disease. Only up to 20% of patients are diagnosed in early-stage, suitable for the curative surgery. Despite the surgery performed with potentially-curative intent, recurrence rates are high, around 60-70% of patients expected to have disease recurrence. In this review, we present an update of the causes, diagnosis, and treatment with a focus on chemotherapy of BTC.

Acute cholecystitis (AC), defined as inflammation of the gallbladder, is mainly caused by gallstones. Over 90% of AC results from obstruction of the cystic duct by stones or sludge, which subsequently increases the intraluminal pressure within the gallbladder and, in conjunction with the presence of bile supersaturated with cholesterol, activates an acute inflammatory cascade. Clinical features play an important role in the diagnosis of AC. The Tokyo Guidelines 2018 for acute cholecystitis designates the presence of local inflammatory signs and systemic inflammatory signs for a suspected diagnosis. It requires confirmation by radiological imaging along with these two factors for a definitive diagnosis. Thanks to less invasiveness, easy availability, ease of use, and cost-effectiveness, ultrasound (US) is usually accepted as the first choice in suspicious AC patients. A meta-analysis comparing methods of diagnosis for AC reported that the US has 81% of sensitivity and 83% of specificity. Abdominal computed tomography is recommended for diagnosing emphysematous or gangrenous cholecystitis. Meanwhile, acute acalculous cholecystitis (AAC) is a life-threatening disease mainly in severely ill patients. It usually affects the patients hospitalized for multiple trauma, burns, cardiopulmonary bypass surgery, long-term total parenteral nutrition or sepsis. The diagnosis of AAC is quite challenging and requires a high index of suspicion. Currently, cholecystectomy is the treatment of choice for AC, although the optimal time for surgery is still controversial. Due to high morbidity and mortality in high surgical risk groups, percutaneous gallbladder drainage can be a safe and feasible alternative to cholecystectomy, particularly for patients unfit for the surgery.

Pancreatic acinar cell carcinoma (ACC) is a rare neoplasm accounting less than 1% of malignant pancreatic tumors. A 47-year-old male patient visited the emergency room with epigastric pain. Computed tomography or magnetic resonance imaging revealed a 4.7-cm heterogeneously enhanced solid and cystic mass with internal necrosis located in the head of the pancreas. Radiological diagnosis was borderline malignancy such as neuroendocrine tumor or solid pseudopapillary neoplasm. Two months later, the necrotic mass in the pancreas head had grown up to 11 cm, compressing the duodenum, superior mesenteric vein, and proximal transverse colon. Pylorus preserving pancreatoduodenectomy with segmental resection of transverse colon was performed. Histopathological examination revealed that the tumor was pancreatic ACC. The patient recovered without any complication and was doing well without recurrence for 12 months after surgery.