Pancreatic fluid collections: Physiology, natural history, and indications for drainage

• Published in: Techniques in gastrointestinal endoscopy 2012-10, Vol.14 (4), p.186-194
• Main Authors: Elkhatib, Imad, MD, Savides, Thomas, MD, Fehmi, Syed M. Abbas, MD, MSc
• Format: Article
• Language: English
• Subjects: Gastroenterology and Hepatology; Pancreatic fluid collections; Postnecrotic pancreatic fluid collection; Pseudocysts; Walled-off pancreatic necrosis
• ISSN: 1096-2883; 1558-5050
• DOI: 10.1016/j.tgie.2012.06.003

Abstract Pancreatic fluid collections (PFCs) are a common manifestation of pancreatitis and can be seen in up to 50% of cases. Advances in cross-sectional imaging techniques have led to a greater understanding of the natural history of PFCs. This, combined with a lack of uniformity in the nomenclature of PFCs, has led to the revised Atlanta Criteria for pancreatic fluid collections, which designates 4 main types: acute peri-PFC (APFC), postnecrotic PFC (PNPFC), pancreatic pseudocyst, and walled-off pancreatic necrosis (WOPN). Each of these fluid collections can be either sterile or infected. When present for >4 weeks from onset of acute pancreatitis, APFCs and PNPFCs become pseudocysts and WOPN, respectively. Rarely, cystic neoplasms can be mistaken for fluid collections, and distinguishing between the two is essential. APFC is common, the majority is self-limited, and therefore, treatment is not recommended unless infected. Pseudocysts have a mature wall and no intracystic necrosis, and can cause symptoms via compressive effects. Multiple factors of pseudocysts such as size, duration, and pancreatic ductal anatomy have been evaluated in attempts to predict their natural history. The presence of symptoms or infection should be the main indication for drainage, whereas size and duration are no longer strong indications for intervention. PNPFCs are seen in the setting of acute pancreatitis with necrosis; they have an unclear natural history, and when present for >4 weeks, they become WOPN. WOPN have mature walls and a variable amount of intracystic necrosis and debris. Distinguishing WOPN from pseudocysts is important and has therapeutic implications. PFCs can be diagnosed with contrast-enhanced computed tomography in most cases, although magnetic resonance imaging provides superior distinction of pancreatic ductal anatomy, necrosis, and intracystic debris and solid material. Endoscopic ultrasonography offers highly accurate views of fluid collections and is especially useful when endoscopic drainage is planned. Stronger adherence to uniform nomenclature, and more natural history studies for each type of PFC, will help us better understand and manage PFCs.