oa Editorial [Hot topic: Current Trends in the Prevention and Treatment of Infection in the Setting of Acute Pancreatitis (Guest Editors: Spiros G. Delis and Christos Dervenis)

Acute pancreatitis is a dynamic, evolving process with a two distinctly different clinical phases of the evolution of the disease. Mild disease is also called interstitial pancreatitis and the clinical features of this entity is strongly related to the inflammatory process and the acute -phase proteins released from the liver. In the other side of the spectrum, severe disease is defined as involving either a local or systemic complication. In the early phase usually within the first week the severity is related to organ failure due to SIRS (systemic inflammatory response) but local or systemic infection is not present. In the second phase the disease either resolves or progress to necrotizing pancreatitis with changes in the pancreatic morphology. This phase last weeks to months and it is related to the necrotizing process. Mortality in this second protracted phase is correlated with infection of pancreatic necrosis. Morphologic criteria and presence of local or systemic complications are applied to determine severity of the inflammatory process and are used potentially to treatment selection. Infected pancreatic necrosis is a secondary infection of the pancreas and peri-pancreatic tissues affecting 40-70% of patients with severe disease in the late phase. Infected necrosis is located retroperitonealy and usually extends towards the paracolic gutters. It occurs by bacteria spread from the gastrointestinal tract, biliary tree or by iatrogenic intervention. Depending on the stage of the necrosis and the organism involved, the infected pancreatic necrosis will have varying amounts of suppuration. In the later stages, the content may be predominantly pus as the process of liquefaction necrosis matures. The presence of infection can be presumed based on the appearance of gas within the area of infected pancreatic or peri-pancreatic necrosis in the non-enhancing area on Computing Tomography. However diagnosis can be established based only by image-guided, fine needle aspiration (FNA) with a Gram positive stain or culture. Distinction between sterile and infected necrosis is important, because the presence of infection confers a different natural history, prognosis and management. Patients with infection require active intervention by means of operative, percutaneous or endoscopic necrosectomy. Attempts to reduce mortality in acute pancreatitis, by preventing infectious complications with prophylactic antibiotics or probiotics are promising although much controversy exists. Recently bacteremia is considered as a prognostic marker to raise the level of suspicion for infected necrosis. It is also clear that half of relevant infections occur in the first few days of acute pancreatitis providing support to the concept of early antibiotic prophylaxis. Recent randomized trials of antibiotic prophylaxis, commencing treatment in the first 72-120 h after onset of symptoms. Results from a recent randomized trial showing a significant reduction in extrapancreatic sepsis by starting antibiotic prophylaxis on admission to hospital, support this suggestion. In addition antibiotics on admission and early enteral nutrition are attractive options for randomized trials. Enteral nutrition is of paramount importance in the early prevention of pancreatic infection and minimizes the risk of antibiotic-resistant bacteria and fungi as a result of antibiotic prophylaxis. In this supplement a focus in both pathophysiology of infection in acute pancreatitis and a thorough review of the literature regarding prevention and treatment of infected necrosis from the prospect of experts in pancreatic surgery is performed.