While the Revised Atlanta Classification outlines the primary complications of acute pancreatitis, it is crucial to recognize additional factors that contribute to morbidity and mortality associated with acute pancreatitis. In this review, we discuss the imaging-based classification and staging of acute pancreatitis as described by the Revised Atlanta Classification, but also provide a comprehensive understanding of the pancreatic anatomy and its relation to surrounding structures, which is essential for imaging-based assessment of both acute pancreatitis and its complications. We further extend the discussion beyond common complications such as pseudocysts and walled-off necrosis to include lesser-known but significant complications such as peripancreatic infection, disconnected ductal disconnection syndrome, thrombosis, hemorrhage, and gastrointestinal complications. Additionally, illustrative examples are presented to highlight relevant points pertaining to real-life imaging assessment of acute pancreatitis and its complications.

BACKGROUND: Pancreaticopleural fistula is a rare complication of pancreatitis and poses diagnostic and therapeutic challenges. This case report sheds light on the unique challenges posed by pancreaticopleural fistula as a rare complication of pancreatitis. The aim is to contribute valuable insights to the scientific literature by presenting a case involving a middle-aged man with acute necrotizing pancreatitis and associated pleural effusion.
METHODS: A 41-year-old Asian male with a history of pancreatitis and chronic alcohol use presented with severe dyspnea, chest pain, and left-sided pleural effusion. Elevated serum amylase lipase levels and imaging confirmed acute necrotizing pancreatitis with a computed tomography severity index of 8/10. Magnetic resonance cholangiopancreatography revealed pancreatic necrosis and pseudocyst formation and findings suggestive of pancreaticopleural fistula. The patient was then treated with octreotide therapy.
CONCLUSIONS: The management of pancreaticopleural fistula demands a comprehensive and individualized approach. Recognition guided by high clinical suspicion coupled with appropriate investigations and a careful balance between medical, endoscopic, and surgical interventions is crucial for achieving favorable outcomes. This case report adds to the scientific literature by providing insights into the complexities of pancreaticopleural fistula and emphasizing the importance of personalized strategies in its management.

Emphysematous pancreatitis represents the presence of gas within or around the pancreas on the ground of necrotizing pancreatitis due to superinfection with gas-forming bacteria. This entity is diagnosed on clinical grounds and on the basis of radiologic findings. Computed tomography is the preferred imaging modality used to detect this life-threating condition. The management of emphysematous pancreatitis consists of conservative measures, image-guided percutaneous catheter drainage or endoscopic therapy, and surgical intervention, which is delayed as long as possible and undertaken only in patients who continue to deteriorate despite conservative management. Due to its high mortality rate, early and prompt recognition and treatment of emphysematous pancreatitis are crucial and require individualized treatment with the involvement of a multidisciplinary team. Here, we present a case of emphysematous pancreatitis as an unusual occurrence and discuss disease features and treatment options in order to facilitate diagnostics and therapy.

Infected necrotizing pancreatitis (INP) is associated with an increased risk of organ failure and mortality. Its early recognition and timely initiation of antibiotic therapy can save patients\' lives. We systematically searched three databases on 27 October 2022. In the eligible studies, the presence of infection in necrotizing pancreatitis was confirmed via a reference test, which involved either the identification of gas within the necrotic collection through computed tomography imaging or the examination of collected samples, which yielded positive results in Gram staining or culture. Laboratory biomarkers compared between sterile necrotizing pancreatitis and INP were used as the index test, and our outcome measures included sensitivity, specificity, the receiver operating characteristic (ROC) curve and area under the ROC curve (AUC). Within the first 72 hours (h) after admission, the AUC of C-reactive protein (CRP) was 0.69 (confidence interval (CI): 0.62-0.76), for procalcitonin (PCT), it was 0.69 (CI: 0.60-0.78), and for white blood cell count, it was 0.61 (CI: 0.47-0.75). After the first 72 h, the pooled AUC of CRP showed an elevated level of 0.88 (CI: 0.75-1.00), and for PCT, it was 0.86 (CI: 0.60-1.11). The predictive value of CRP and PCT for infection is poor within 72 h after hospital admission but seems good after the first 72 h. Based on these results, infection is likely in case of persistently high CRP and PCT, and antibiotic initiation may be recommended.

OBJECTIVE: In patients with acute pancreatitis (AP), minimally invasive treatment and the step-up approach have been widely used to deal with infected pancreatic necrosis (IPN) in the last decade. It is unclear whether IPN has become a less important determinant of mortality relative to organ failure (OF). We aimed to statistically aggregate recent evidence from published studies to determine the relative importance of IPN and OF as determinants of mortality in patients with AP (PROSPERO: CRD42020176989).
METHODS: Relevant studies were sourced from MEDLINE and EMBASE databases. Relative risk (RR) or weighted mean difference (WMD) was analyzed as outcomes. A two-sided P value of less than 0.05 was regarded as statistical significance.
RESULTS: Forty-three studies comprising 11 601 patients with AP were included. The mortality was 28% for OF patients and 24% for those with IPN. Patients with OF without IPN had a significantly higher risk of mortality compared to those with IPN but without OF (RR 3.72, P < 0.0001). However, patients with both OF and IPN faced the highest risk of mortality. Additionally, IPN increased length of stay in hospital for OF patients (WMD 28.75, P = 0.032).
CONCLUSIONS: Though IPN remains a significant concern, which leads to increased morbidity and longer hospital stay, it is a less critical mortality determinant compared to OF in AP.

Acute pancreatitis is a common condition of the digestive system, but sometimes it develops into severe cases. In about 10-20% of patients, necrosis of the pancreas or its periphery occurs. Although most have aseptic necrosis, 30% of cases will develop infectious necrotizing pancreatitis. Infected necrotizing pancreatitis (INP) requires a critical treatment approach. Minimally invasive surgical approach (MIS) and endoscopy are the management methods. This meta-analysis compares the outcomes of MIS and endoscopic treatments.
We searched a medical database until December 2022 to compare the results of endoscopic and MIS procedures for INP. We selected eligible randomized controlled trials (RCTs) that reported treatment complications for the meta-analysis.
Five RCTs comparing a total of 284 patients were included in the meta-analysis. Among them, 139 patients underwent MIS, while 145 underwent endoscopic procedures. The results showed significant differences (p < 0.05) in the risk ratios (RRs) for major complications (RR: 0.69, 95% confidence interval (CI): 0.49-0.97), new onset of organ failure (RR: 0.29, 95% CI: 0.11-0.82), surgical site infection (RR: 0.26, 95% CI: 0.07-0.92), fistula or perforation (RR: 0.27, 95% CI: 0.12-0.64), and pancreatic fistula (RR: 0.14, 95% CI: 0.05-0.45). The hospital stay was significantly shorter for the endoscopic group compared to the MIS group, with a mean difference of 6.74 days (95% CI: -12.94 to -0.54). There were no significant differences (p > 0.05) in the RR for death, bleeding, incisional hernia, percutaneous drainage, pancreatic endocrine deficiency, pancreatic exocrine deficiency, or the need for enzyme use.
Endoscopic management of INP performs better compared to surgical treatment due to its lower complication rate and higher patient life quality.

BACKGROUND: Walled-off necrosis (WON) is highly morbid disease most effectively managed by endoscopic drainage with lumen-apposing metal stents (LAMSs) or plastic stents, with or without necrosectomy. This meta-analysis compared the clinical outcomes of patients included in randomized trials treated using LAMSs or plastic stents.
METHODS: The MEDLINE and EMBASE databases were searched to identify all data collected from randomized trials comparing LAMSs and plastic stents for the treatment of WON. The primary outcome measure was need for endoscopic necrosectomy.
RESULTS: Three studies comprising 206 patients met inclusion criteria. Except for procedure duration, which was significantly shorter for LAMSs (standardized mean difference [SMD] -1.22, 95%CI -1.64 to -0.79), there was no significant difference in need for necrosectomy (38.5% vs. 41.2%; risk ratio [RR] 1.07, 95%CI 0.79-1.45), number of interventions (SMD -0.09, 95%CI -0.40 to 0.22), treatment success (90.7% vs. 94.5%; RR 0.96, 95%CI 0.87-1.06), recurrence (4.6% vs. 0.6%; RR 3.73, 95%CI 0.42-33.0), readmission (42.6% vs. 50.2%; RR 0.84, 95%CI 0.62-1.14), length of hospitalization (SMD -0.06, 95%CI -0.55 to 0.43), mortality (8.5% vs. 9.8%; RR 0.70, 95%CI 0.30-1.66), new-onset organ failure (10.6% vs. 14.6%; RR 0.72, 95%CI 0.16-3.32), bleeding (11.0% vs. 10.7%; RR 1.09, 95%CI 0.34-3.44), procedural adverse events (23.6% vs. 19.2%; RR 1.38, 95%CI 0.82-2.33), or overall costs (SMD -0.04, 95%CI -0.31 to 0.24) between LAMSs and plastic stents, respectively.
CONCLUSIONS: Except for procedure duration, there is no significant difference in clinical outcomes for patients with WON treated using LAMSs or plastic stents.

OBJECTIVE: Postponed open necrosectomy or minimally invasive intervention has become the treatment option for necrotizing pancreatitis. Nevertheless, several studies point to the safety and efficacy of early intervention for necrotizing pancreatitis. Therefore, we conducted a systematic review and meta-analysis to compare clinical outcomes of acute necrotizing pancreatitis between early and late intervention.
METHODS: Literature search was performed in multiple databases for articles that compared the safety and clinical outcomes of early (<4 weeks from the onset of pancreatitis) versus late intervention (≥4 weeks from the onset of pancreatitis) for necrotizing pancreatitis published up to August 31, 2022. The meta-analysis was performed to determine pooled odds ratio (OR) of mortality rate and procedure-related complications.
RESULTS: Fourteen studies were included in the final analysis. For open necrosectomy intervention, the overall pooled OR of mortality rate with the late intervention compared with early intervention was 7.09 (95% confidence interval [CI] 2.33-21.60; I2  = 54%; P = 0.0006). For minimally invasive intervention, the overall pooled OR of mortality rate with the late intervention compared with early intervention was 1.56 (95% CI 1.11-2.20; I2  = 0%; P = 0.01). The overall pooled OR of pancreatic fistula with the late minimally invasive intervention compared with early intervention was 2.49 (95% CI 1.75-3.52; I2  = 0%; P < 0.00001).
CONCLUSIONS: These results showed the benefit of late interventions in patients with necrotizing pancreatitis in both minimally invasive procedures and open necrosectomy. Late intervention is preferred in the management of necrotizing pancreatitis.

Minimally invasive step-up interventions are now the standard treatment recommended by current guidelines for symptomatic pancreatic necrotic fluid collections (PNFC); however, it is controversial whether delayed treatment after four weeks should always be used in patients who have failed conservative treatment and whose condition has not improved or worsened. The aim of this meta-analysis was to evaluate the impacts of the different timing of interventions on the clinical outcomes and prognosis of patients with symptomatic PNEC requiring intervention.
We searched Embase, Cochrane Library, PubMed and Web of Science databases to identify comparative studies assessing the safety and efficacy of early and postponed interventions in treating symptomatic PNFC.
Mortality. Secondary outcomes included some major complications, need for further minimally invasive necrosectomy and length of hospital stay.
This meta-analysis included ten studies (2 RCTs and 8 observational studies) with a total of 1178 symptomatic PNFC patients who required intervention. Pooled results showed that there was no significant difference between early minimally invasive intervention and postponed intervention in mortality(OR 1.41, 95%CI 0.93-2.12;p = 0.10) and the incidence of early and late complications, but the early intervention group had a significantly increased need for further minimally invasive necrosectomy compared with postponed intervention (OR 2.04,95%CI 1.04-4.03; p = 0.04). There was no increase in length of stay for patients who received early intervention compared to postponed drainage (MD 3.53, 95% CI -4.20, 11.27; p = 0.37).
Intervention before four weeks should be considered for patients with PNFC complicated by persistent organ failure or infections, who have been treated conservatively to the maximum extent possible.

BACKGROUND: Nowadays, minimally invasive intervention (MII) has largely replaced delayed open surgery in acute necrotizing pancreatitis (ANP). However, the timing of MII remains unclear. The present study investigated the effect of early versus delayed MII on complications in ANP.
METHODS: Studies evaluating the impact of the timing of MII on complications in ANP patients were thoroughly searched on PubMed, Embase, Cochrane Library, and Web of Science from inception to June 2022. The primary outcome of interest was mortality. Secondary outcomes were the incidence of complications.
RESULTS: Nine studies reporting 870 patients undergoing MII for ANP were included. No significant difference was found in mortality between the early and delayed intervention groups. In addition, the timing of MII was not associated with the incidence of new-onset respiratory failure, new-onset cardiovascular failure, new-onset renal failure, new-onset multiple organ failure, gastrointestinal fistula or perforation, pancreatic fistula, stent migration, bleeding, venous thrombosis, and new-onset pancreatic endocrine insufficiency. Notably, in the subgroup analysis of biliary and Asian ANP patients, early intervention was associated with a significantly higher risk of new-onset renal failure than delayed intervention.
CONCLUSIONS: Early intervention is safe and recommended only for patients with indications for intervention, such as infection.