Pancreatic pseudocysts (PP)
Discuss pancreatic pseudocysts?
Pancreatic pseudocysts are complications of acute or chronic pancreatitis. Pseudocysts are localized fluid collection that is rich in amylase and other pancreatic enzymes and is surrounded by a wall of fibrous tissue that is not lined by epithelium.
What are the different types of pseudocysts?
D’Egidio and Schein define three distinct types of pseudocysts.
- Type I, or acute “post-necrotic” pseudocysts that occur after an episode of acute pancreatitis and are associated with normal duct anatomy, and rarely communicate with the pancreatic duct.
- Type II, also post-necrotic pseudocysts, which occurs after an episode of acute-on-chronic pancreatitis (the pancreatic duct is diseased, but not strictured, and there is often a duct-pseudocyst communication).
- Type III, defined as “retention” pseudocysts, occur with chronic pancreatitis and are uniformly associated with duct stricture and pseudocyst duct communication.
Discuss the aetiology of pseudocysts?
Pseudocysts seems to form from disruptions of the pancreatic duct due to pancreatitis
or trauma followed by extravasation of pancreatic secretions. Majority of patients with pseudocysts have demonstrable connections between the cyst and the pancreatic duct. In other patients, an inflammatory reaction most likely sealed the connection so that it is
not demonstrable.
Discuss the clinical features of pseudocysts?
They can be asymptomatic or present with one of the complications. The most common symptoms are nausea, vomiting and abdominal pain.
Discuss the complications of pseudocyst?
- Infection
- Obstruction- luminal (gastric- causing n&v), vascular (splenic or portal vein thrombosis giving rise to gastric varices) or biliary (may present with obstructive jaundice or cholangitis)
- Bleeding- from pseudo aneurysms can present as an acute intra- or retroperitoneal bleed. Pseudo aneurysms are treated by angiographic embolization.
- Rupture of the pseudocyst in the GIT or peritoneum or the vasculature
Discuss the diagnosis of pseudocyst?
Diagnosis is by USS or CT scan.
Once a pancreatic cyst is diagnosed, a pseudocyst will need to be differentiated from other cystic lesions like cystic neoplasm, a benign or an incidental cyst. The clues which favour a pseudocyst are: evidence of chronic pancreatitis, preceding h/o acute pancreatitis, extra pancreatic location, communication with PD and high fluid amylase content. EUS and analysis of the aspirated cyst fluid may help differentiate pseudocysts from cystic tumours of the pancreas
Discuss the management of pancreatic pseudocyst?
40% of pts with pancreatitis will have acute fluid collection. 80% of them resolve on their own- hence only follow up scan needed in 3-4 weeks after discharge. 20% will go on form a pseudocyst. 50% of these pseudocysts will stabilise or disappear and the other 50% will be clinically relevant.
Initial management consists of supportive care. Persistent symptoms and the development of complications warrant invasive intervention.
What are the indications for intervention in pancreatic pseudocyst?
Absolute size of 6cm is no longer a sole indication for intervention. However, treatment is needed if they are causing symptoms or if there is any sign of complications like infection, obstruction or bleeding.
How do you choose an appropriate therapy?
Pseudocysts can be treated by various methods: surgical, percutaneous or endoscopic. There are no randomized trials comparing any of these approaches. As a result, the management varies based on local expertise but in general endoscopic drainage is becoming the preferred approach.
- Percutaneous- using USS, a pigtail is catheter is placed percutaneously in the fluid cavity and the fluid drained. The catheter stays in till the fluid output becomes minimal. This may take weeks. This method has a high risk of infection and a success rate of only 50% for successful resolution of the cyst. Unsuccessful drainages are usually caused by large ductal leaks.
- Surgical- drainage is achieved by providing a communication between the pseudocyst and the stomach or the small bowel. This approach to drainage is often reserved for those patients that cannot tolerate or have failed percutaneous or endoscopic drainage.
- Endoscopic drainage- has become the preferred therapeutic approach. Drainage is accomplished with either a transpapillary approach with ERCP or direct drainage across the stomach or duodenal wall. A transpapillary approach is used when the pseudocyst communicates with the main pancreatic duct. A transgastric or transduodenal approach is used (with EUS) when the pseudocyst is directly adjacent to the gastroduodenal wall. A distance between the gastric or duodenal wall and cyst wall of more than 1 cm or the presence of large intervening vessels or varices are relative contraindications for endoscopic drainage
Discuss the supportive medical care for pancreatic pseudocysts?
- Low fat diet
- The logic of octreotide therapy for pancreatic pseudocyst is that it will decrease pancreatic secretions and aid in pseudocyst resolution. However, this strategy has not been rigorously tested.
- Most pseudocysts tend to resolve with supportive medical care.
Ref
?
