Endoscopic Retrograde Cholangiopancreatography (ERCP)

Endoscopic retrograde cholangiopancreatography (ERCP) is used both in the diagnosis and treatment of many pancreatic and biliary diseases. It was first used in the 1970s at which point its main use was in diagnosis - in contrast to nowadays when its use is mostly as a therapeutic tool.

Provides detailed and accurate information of the pancreaticobiliary system.

• Choledocholithiasis (e.g. gallstones in common bile duct and microlithiasis)
• Acute pancreatitis due to biliary obstruction, sphincter of Oddi dysfunction or idiopathic, recurrent cases
• Detection of pancreatic divisum (more commoner in patients who develop pancreatitis but may not necessarily be causal)¹
• Diagnosis of pancreatic and biliary malignancy (although endoscopic ultrasound may be superior)
• Palliative therapy for inoperable pancreaticobiliary malignancies e.g. drainage procedures
• Dilatation of benign strictures e.g. following orthoptic liver transplantation²
• Chronic pancreatitis - very controversial but there may be a role for dilatation of strictures or stent insertion³
• Manometry measures in Sphincter of Oddi dysfunction

ERCP and choledocholithiasis³

One method for determining who should have an ERCP is to classify patients in to low, intermediate or high risk.

• Low risk patients should proceed to laparoscopic cholecystectomy without further intervention or imaging procedures.
• Intermediate risk patients include those with features such as, previous history of cholangitis or pancreatitis, slightly abnormal liver function tests (e.g. raised ALP but less than twice normal), dilated CBD between 8-10 mm. This group of patients should have further tests e.g. endoscopic ultrasound before deciding on further intervention.
• High risk patients include those with recent cholangitis, recent acute pancreatitis, jaundice, abnormal LFT's (ALP more than twice normal), dilated CBD >10 mm. This group will benefit most from ERCP. However, even a third of these patients will fail to have a stone on ERCP and further investigation may be needed.

ERCP and acute pancreatitis

• Acute pancreatitis with evidence of biliary tract obstruction should have urgent ERCP.
• At ERCP sphincterotomy may be performed to remove duct obstruction e.g. gallstone.
• However, there is a risk that pancreatitis may be worsened.
• A meta-analysis of studies looking at the role of ERCP in acute biliary pancreatitis have confirmed that early ERCP reduces both complications and mortality rates.¹
• Sphincter of Oddi dysfunction can lead to pancreatitis - usually in women following cholecystectomy and responds to isolated biliary sphincterotomy.

• ERCP is performed on an out-patient or in-patient basis
• Patients have to fast overnight
• Patients are usually sedated for the procedure e.g. using midazolam and analgesia is also given
• Patients usually lie on their left side
• The back of throat is sprayed with a local anaesthetic
• The endoscope is passed down through to the stomach and then to the duodenum (where the ducts of the pancreaticobiliary system open, called the ampulla of vater)
• Air may be pumped in to the duodenum to allow better visualisation
• Using a wire passed through the endoscope contrast is injected through the ampulla of vater and x rays obtained
• These images will indicate areas of obstruction
• Further intervention can be performed down the endoscope if necessary e.g. stone removal, stent insertion, biopsies

• Pancreatitis - 2-9% of patients will develop pancreatitis and it is seen especially in endoscopic sphincterotomy for Sphincter of Oddi dysfunction.^1,4 Majority of cases are mild but 10% of cases are moderate to severe and may lead to multiorgan failure and even death. The chances of pancreatitis post-ERCP can be reduced by avoiding excessive cannulation trauma and stent insertion - the latter being the most effective method.⁵ Stent insertion allows pancreatic secretions to pass freely.
• Infection may occur - although rates are low.
• Bleeding may occur - although severe haemorrhage is rare.
• Perforation of duodenum with development of an acute abdomen.
• Failure of gallstone retrieval - may need to revert to open or more invasive procedures.
• Prolonged pancreatic stenting is associated with stent occlusion, pancreatic duct obstruction, and pseudocyst formation.