Most of the gastrointestinal (G.I.) tract from the esophagus to the anus can be examined by endoscopy (endo, inside; scope, see; to see inside the body). The endoscope is a long and flexible tube and contains a light source, lens system for focusing and fiber optics to conduct light into the bowel. A picture of the bowel wall is sent back to a video camera and displayed on a monitor. The tube also contains a working channel through which small instruments can be passed for various uses.
ERCP is a specialized technique similar to panendoscopy (see Panendoscopy) that is used for diagnosing many diseases of the pancreas and biliary (bile) ducts. The biliary ducts (channels) drain the liver. ERCP involves the passage of a tube by mouth through the esophagus into the stomach and into the duodenum. It allows the physician to study the ducts of the gallbladder, pancreas and liver by inserting a catheter (thin tube) through the working channel of the endoscope into the ducts and injecting a dye that can be seen on an X-ray monitor.
Anatomy and Physiology
- The duodenum connects the stomach to the jejunum (the second part of the small bowel) (Figure 1) (See Surgery of the Duodenum)
- It is 20 cm (8 inches) in length and divided into four parts
- The duodenum is retroperitoneal (has peritoneum, the thin layer of tissue that lines the abdominal cavity) only on the anterior (front) side; fixed in location; wraps around the head, neck and body of the pancreas; and the superior mesenteric artery and vein (major blood vessels for the bowel) pass anterior to the 3rd portion.
- The ampulla of Vater (entrance site into duodenum of joined common bile duct and pancreatic duct) enters the medial (towards the midline) side of the 2nd portion of the duodenum.
- The accessory pancreatic duct enters slightly higher in the medial wall of the duodenum
- The ligament of Treitz (a supporting band of peritoneum and muscle fibers) marks the point between the fourth part of the duodenum and jejunum
- The duodenum produces many hormones that help regulate digestion. Liver bile and pancreatic secretions are added to the bowel through the ampulla of Vater. The actual passage and presence of food in the duodenum triggers the flow of hormones, bile and pancreatic secretions. By the time food leaves the duodenum most of the ingredients necessary for digestion have been added. Little digestion and absorption (passage of nutrients from the bowel into the blood) take place in the duodenum
|Figure 1 - Anatomy of the duodenum, liver, biliary ducts and stomach. © N. Gordon |
- ERCP is used for the following diseases in the duodenum and bile and pancreatic ducts
- Stones within the duct system (Figure 2)
- Strictures (narrowing by scar tissue or tumor) of the ducts or ampulla of Vater (Figure 3)
- Tumors of the ampulla, biliary ducts or pancreatic ducts (Figure 4)
2 - Stone impacted in the ampulla of Vater. Courtesy M. Takriti, MD || Figure
3 - Stent placed in an ampullary stricture. Bile is released with dilatation of the stricture. Courtesy M. Takriti, MD |
|Figure 4 - Tumor of the ampulla of Vater. Courtesy M. Takriti, MD |
- Severe or persistent abdominal pain that suggests biliary or pancreatic disease
- Jaundice (yellow discoloration of the eyes) - to determine if it is caused by a disease such as hepatitis, which is treated medically, or by structural diseases such as gallstones, tumors or strictures which are treated endoscopically or surgically
- Non-jaundiced patient that has laboratory test results that suggest biliary or pancreatic disease
- ERCP can be used to determine whether or not surgery is necessary and is helpful in providing the anatomic detail the surgeon needs to plan an operation when surgery is necessary
- Symptoms, physical examination, laboratory tests or x-ray films that suggest structural abnormalities that can be shown in detail by ERCP
- Sometimes biopsies can be carried out on abnormal tissues
- The information provided by an ERCP is more detailed than that provided by standard x-ray films or scans
- Therapeutic ERCP can open the end of the bile duct, extract stones and place stents (plastic drainage tubes across the obstructed ducts to improve their drainage)
- The physician performing the procedure should be informed of any medications that the patient takes regularly, drug allergies or any heart or lung conditions or any other major disease. An allergy to iodine containing drugs (contrast material or dye) is not a contraindication to ERCP. The physician should know about the allergy so that a non-iodine contrast material can be used
- Women of child-bearing age should tell the physician if they are pregnant because x-ray films or scans may be taken during the procedure
- The patient should be fasting for at least six hours before the procedure and preferably overnight. It is necessary to have a completely empty stomach for the best possible examination
- The patient is given sedation; therefore, the procedure carries little or no discomfort
- Some patients also receive antibiotics
- The throat may be sprayed with a topical anesthetic
- The test begins with the patient lying prone (face down).
- An endoscope is passed through the mouth, esophagus and the stomach into the duodenum. The instrument does not interfere with the breathing and the saliva is easily and readily suctioned. Air is introduced through the endoscope and may cause temporary bloating during and after the procedure.
- After the ampulla is visually identified, a catheter is passed through the endoscope into the ducts (Figure 5)
- Contrast material is injected gently into the ducts (pancreatic or biliary) and X-ray films are taken. The injection of contrast material into the ducts rarely causes discomfort
- With therapeutic ERCP, special small instruments are passed through the working channel of the endoscope that are used for cutting and opening into the bile duct, gallstone removal, dilatation of a stricture or stent or drain placement
|Figure 5 - Catheter inserted in the ampulla of Vater. Courtesy M. Takriti, MD|
- Localized irritation of the vein into which medications were given may rarely cause a tender lump that may last several weeks. The application of hot packs or hot moist towels to the area may reduce the discomfort
- Major complications requiring hospitalization can occur, but are uncommon during diagnostic ERCP. If therapeutic ERCP is performed the possibility of complications is higher than with diagnostic ERCP. These include:
- Severe pancreatitis
- Bowel perforation
- These risks must be balanced against the potential benefits of the procedure and whether there is alternative surgical treatment of the condition. Often these complications can be managed without surgery, but occasionally they may require corrective surgery.
- A potential risk is an adverse reaction to the sedative
- If a complication occurs, the patient might need to be hospitalized until the complication is resolved
- After the test patients are monitored in the recovery area for 30 - 45 minutes, until the effects of sedation have worn off. They will need to make arrangements for somebody to drive them home (not a taxi) and to stay with them for the remainder of the day because sedation affects judgment and reflexes for the rest of the day. No driving or work is allowed until the next day
- The throat may be a sore for a while and can be soothed with throat lozenges
- The patient might feel bloated after the procedure because of the air introduced into the stomach during the test
- The patient should be able to resume a normal diet after the procedure unless instructed otherwise
- The doctor will discuss with the patient any further instructions or need for follow up