Collections post-pancréatite aiguë.

Pancreatic or peri pancreatic collections are the most frequent complication of acute pancreatitis. To make the difference between acute edematous and necrotic pancreatitis is crucial to choose the optimal therapeutic approach. Since the Atlanta classification, the different types of collections are well defined. During the first 4 weeks after acute pancreatitis onset, the pancreatic fluid collections (no clear wall, frequently related to an acute edematous pancreatitis with a spontaneously good evolution in most cases) and acute necrotic collections (with a variable solid component and frequently related to an acute necrotic pancreatitis) have been described. After 4 weeks, pancreatic pseudocysts (well-defined liquid collection with no solid component) and Walled-Off Necrosis (or WON, a capsulated collection with solid component) can be found. In 50% of cases, pancreatic collections (pseudocyst or WON) spontaneously disappear, without the need for drainage. Morphological follow-up is therefore recommended. Only symptomatic collections presenting with compression of a neighboring organ (stomach, duodenum, biliary tract), or infection of necrosis need drainage. Endoscopic route should be preferred if they are accessible. The modalities of drainage are based on a minimally invasive approach (called "step-up") as follows: cystostomy under endoscopic ultrasound guidance by metal (lumen-apposing metal stents) or plastic stents (double pigtail design), combined with endoscopic necrosectomy if necessary. Radiological and/or surgical drainage are sometimes necessary, particularly for collections not accessible by endoscopy (parieto-colic gutter, pelvis). [ABSTRACT FROM AUTHOR]