About Pseudocyst Drainage
What are pseudocysts?
Pancreatic pseudocysts are intra- or extra-pancreatic fluid collections composed of pancreatic secretions and inflammatory debris. Reactive granulation tissue rather than a true epithelial lining walls of the fluid collection, hence the term “pseudocyst.” Pseudocysts originate from leaks in the pancreatic duct. The etiology may be necrosis secondary to pancreatitis, progressive ductal obstruction, or trauma.
When is pseudocyst treatment indicated?
The majority of pseudocysts are asymptomatic and do not require treatment. An asymptomatic but large or enlarging pseudocyst may warrant drainage due to rupture or hemorrhage risk. Pseudocysts that complicate acute pancreatitis have a high probability to spontaneously resolve within 4 to 6 weeks and should be observed for this time period before further treatment. Earlier drainage may be indicated when clinical pancreatitis fails to improve despite aggressive medical management.
Pseudocysts complicating chronic pancreatitis usually result from pancreatic duct outflow obstruction, whether this is due to a stone, stricture, or protein plug. Such “retention” pseudocysts rarely resolve on their own. Drainage is indicated to relieve symptoms associated with a space-occupying mass and neighboring organ compression, such as pain, gastric outlet obstruction, and jaundice. Drainage is also indicated when pseudocysts become infected or there is intracystic bleeding.
What are the treatment options?
Surgical drainage by cyst-gastrostomy or cyst-jejunostomy has been the standard treatment. The success rate is high, but surgical management requires an adequately mature pseudocyst wall that will hold sutures. Percutaneous drainage has several drawbacks including skin discomfort and infection and may leave a cutaneous fistula after drainage tube removal. Endoscopic drainage is appealing because it creates a similar result to internal surgical drainage and can treat immature pseudocysts.
How does endosonography (EUS) assist endoscopic pseudocyst drainage?
The application of EUS to guide pseudocyst puncture through the stomach or duodenal wall has improved the success and safety of endoscopic pseudocyst drainage. Using endoscopic guidance alone, a prominent mucosal bulge must be present to identify the site for pseudocyst puncture. Even then, the interposed tissue may contain vessels. EUS provides a highly detailed view of the pseudocyst and surrounding topographical anatomy. surface vessels are readily detected with color Doppler.
How is EUS-guided pseudocyst drainage performed?
The optimal site for pseudocyst puncture is determined by the local EUS anatomy. Color Doppler is used to scan the area for vessels that may be interposed in the needle path (Fig 1). Having determined the site for a puncture, the cyst is punctured with a 19 G cyst puncture needle (Fig 2). After entering the cyst, the stylet is removed and a sample of the cyst contents is aspirated for biochemical analysis and cytological examination. If the cyst appears infected an aspirate is sent for a gram stain and culture. Contrast injection under fluoroscopy is performed to document the size and anatomical boundaries of the cyst and to identify a possible communication with the pancreatic duct. A guide wire is inserted and the drainage tract is dilated with a balloon catheter (6 mm or 8 mm). Finally, double pigtail stents are used to drain the cyst into the stomach or duodenum. If the cyst appears infected or contains necrotic debris, a nasocystic catheter is inserted for cyst irrigation. Once the cyst contents are clear, the nasocystic catheter is exchanged for a stent to maintain drainage.
What happens after stent drainage?
Patients are kept on antibiotics until complete cyst resolution is documented by computed tomography (CT). Most pseudocysts will resolve 10 to 14 days after stent drainage. The stent is removed 1 to 2 months after cyst resolution to allow the cyst wall to scar down.