Post acute pancreatitis collections

Pancreatic or peri-pancreatic collections are the most frequent complication of acute pancreatitis. To choose the optimal therapeutic approach, it is important to distinguish between acute edematous and necrotic pancreatitis. The different types of collections have been clearly defined by the revised Atlanta classification. In the first 4 weeks after acute pancreatitis onset, we refer to acute pancreatic fluid collections (no clear wall, often secondary to acute edematous pancreatitis, and resolving spontaneously in most cases) and acute necrotic collections (variably containing a liquid and necrotic component, and often secondary to acute necrotizing pancreatitis). After 4 weeks of evolution, a distinction is made between pancreatic pseudocysts (well-defined liquid collection with no solid component) and Walled-Off Pancreatic Necrosis (or WOPN, a capsulated collection with a solid component). In 50% of cases, pancreatic collections (pseudocysts or WOPN) disappear spontaneously, without the need for drainage. Morphological follow-up is therefore recommended. Only symptomatic collections presenting with compression of a neighboring organ (e.g., stomach, duodenum, or biliary tract), or infection of necrosis require drainage via endoscopy if collections are accessible. Endoscopic drainage is based on a minimally invasive approach (called “step-up”), which involves 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 (e.g., parieto-colic gutter, pelvis).