Pancreatic Pseudocyst

Pancreatic pseudocyst is a peripancreatic fluid collection with a well defined fibrous or granulation tissue wall without epithelial lining, arising more than 4 weeks after acute pancreatitis.

• Complicates 10 to 20% of acute pancreatitis and 20 to 40% of chronic pancreatitis.
• Causes: alcohol, gallstones, trauma, ductal disruption, hypertriglyceridaemia.
• Many resolve spontaneously (up to 40 to 50%), especially under 6 cm.
• Complications: infection, haemorrhage (pseudoaneurysm of splenic or gastroduodenal artery), rupture, obstruction of stomach, duodenum or bile duct, fistula, splenic vein thrombosis.
• Differentiate from walled off necrosis (contains solid debris) and cystic neoplasms (mucinous cystic neoplasm, IPMN, serous cystadenoma).

• Persistent abdominal pain, early satiety, nausea, vomiting, weight loss, palpable epigastric mass.
• Jaundice (bile duct compression), fever (infection), gastrointestinal bleeding.
• Raised amylase or lipase persisting after pancreatitis.
• Acute deterioration with rupture or haemorrhage.

• Contrast CT: thin walled homogeneous fluid collection, no solid component, enhancing wall.
• MRI/MRCP: distinguishes necrotic debris and identifies ductal communication.
• EUS: wall thickness, internal debris, cyst fluid analysis (amylase over 5000 U/L, low CEA below 5 ng/mL differentiates from mucinous neoplasm).
• Doppler or CT angiography for pseudoaneurysm.
• Laboratory: amylase, lipase, liver tests, white count, CRP, blood glucose.
• Exclude cystic neoplasm if no history of pancreatitis.

• Asymptomatic: observation with imaging at 6 to 12 weeks; most resolve.
• Intervention indications: symptoms (pain, obstruction), infection, enlargement, haemorrhage, rupture, suspected neoplasm; size alone (over 6 cm) is not an indication.
• Endoscopic transmural drainage (EUS guided cystogastrostomy or cystoduodenostomy) is first line: lumen apposing metal stents (LAMS, 10 to 20 mm) or double pigtail plastic stents; success over 90%; remove LAMS within 4 weeks to avoid bleeding. Transpapillary drainage for communicating cysts with ductal disruption and main duct stenting.
• Percutaneous catheter drainage for infected collections and unfit patients (risk of external fistula).
• Surgical drainage (laparoscopic or open cystogastrostomy, cystojejunostomy) for complex cysts, failed endoscopic therapy, and when resection is needed.
• Haemorrhage from pseudoaneurysm: angiographic embolisation, then drainage.
• Infection: antibiotics (piperacillin tazobactam 4.5 g every 6 hours, meropenem 1 g every 8 hours) with drainage.
• Optimise nutrition; treat the cause (alcohol, gallstones, hypertriglyceridaemia).
• Follow up imaging to confirm resolution, recurrence rate 5 to 10%.