Investigation Of Extrahepatic Biliary Obstruction Biology Essay

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The liver produces bile, which flows through the ducts, passes or fills the gallbladder and then enters the intestine duodenum just beyond the stomach. The pancreas, which is six to eight inches long, sits behind the stomach. This organ secretes digestive enzymes that flow into the intestine through the same opening as the bile. Both bile and enzymes are needed to digest food.

Endoscopic is inspection of any cavity of the body by means of an endoscope, an instrument that allows illumination of the internal lining of an organ. Various fiber-optic endoscopes are available to examine the interior lining of the stomach, duodenum, and colon. Older types of endoscopes allow for individual viewing only through an eyepiece, but newer video endoscopes project the image onto video monitors for multiple viewing. Also, a special type of fiber-optic endoscopic, called a duodenoscope, is commonly used for an ERCP exam. This instrument, when inserted into the duodenum through the mouth, esophagus, and stomach, provides a wide-angle side view that is useful for locating and inseting a catheter or cannula into the small opening of the sphincter of oddi, leading from the duodenum into the common bile duct and the main pancreatic.

DIAGNOSTIC OR THERAPEUTIC

The ERCP can be either a diagnostic or a therapeutic procedure. Therapeutically, ERCP can be performed to relieve certain pathologic conditions. This can be either the removal of choletiths or small lesions or for other purposes such as to repair a stenosis (narrowing or blockage of a duct or canal) of the hepatopancreatic sphincter or associated ducts.

For diagnostic purposes, in general, the ERCP procedure includes the insertion endoscopically of the catheter or injection cannula into common bile duct or main pancreatic duct under fluoroscopic control, followed by retrograde injection (backward or reverse direction) of contras media into the biliary ducts. The procedure is usually performed by a gastroenterologist assisted by a team including the technologist, one or more nurses, and perhaps a radiologist.

Indications

Investigation of extrahepatic biliary obstruction.

Post-cholecystectomy syndrome.

Investigation of diffuse biliary disease, e.g. sclerosing cholangitis.

Pancreatic disease.

Contraindications

Australia antigen-positive; HIV-positive

Oesophageal obstruction; varices; pyloric stenosis

Previous gastric surgery.

Acute pancreatitis.

Pancreatic pseudocyst.

When glucagon or Buscopan are contraindicated.

Severe cardio/ respiratory

Severe cardio/respiratory disease.

Contrast medium

Pancreas - LOCM 240

Bile ducts - LOCM 150; dilute contrast medium ensures that calculi will not be abscured.

Preliminary film

Prone AP and LAO of the upper abdomen, to check for apaque gallstones and pancreatic calcification/calculi.

Technique

The pharynx is anaesthetized with 4% Xylocaine spray and the patient is given diazepam 5 mg min-1 i.v. until sedated. The patient then lies on the left side and the endoscope is introduced. The ampulla of vater is located and the patient is turned prone. A polythene catheter prefilled with contrast medium is inserted into the ampulla, having ensured that all air bubbles are excluded. A small test injection of contrast under fluoroscopic control is made to determine the position of the cannula it is important to avoid over-filling of the pancreas. If it is desirable to opacity the biliary tree and pancreatic duct, then the later should be cannulated first. A sample of bile should be sent for culture and sensitivity if there is evidence of biliary obstruction.

Films

Pancreas (using fine focal spot) - Prone, both posterior oblique's.

Bile ducts

Early filing films to show calculi

Prone-straight and posterior calculi

Supine-straight, both oblique's; Trendelenburg to fill intrahepatic ducts; semi-erect to fill lower end of common bile duct and gallbladder.

Films following removal of the endoscopic, which may obscure the duct.

Delayed films to assess the gallbladder and emptying of the common bile duct.

Aftercare

Nil orally until sensation has returned to the pharynx (0.5-3 hour).

Pulse, temperature and blood pressure half-hourly for 6 hour.

Maintain antibiotics if there is biliary or pancreatic obstruction.

Serum/urinary amylase if pancreatitis is suspected.

Complications

Due to the contrast medium

Allergic reactions - rare

Acute pancreatitis-more likely with large volumes, high-pressure injections.

Due to the technique

Local - Damage by the endoscopic, e.g. rupture of the oesophagus to the ampulla, proximal pancreatic duct and distal common duct.

Distant - Bacteraemia, septicaemia, aspiration pneumonitis, hyperamylasaemia (approx. 70%). Acute pancreatitis (0.7 - 7.4%).

What is ERCP

ERCP is a diagnostic test to examine the duodenum (the first portion of the small intestine), the papilla of Vater (a small nipple-like structure with openings leading to the bile ducts and the pancreatic duct), the bile ducts, the gallbladder and the pancreatic duct. The procedure is performed by using a long, flexible, viewing instrument (a duodenoscope) about the diameter of a pen. The duodenoscope is flexible and can be directed and moved around the many bends of the stomach and intestine. Two types of duodenoscopes are currently available. A fiber-optic duodenoscope uses a thin fiber-optic bundle to transmit images to the lens at the viewing end of the instrument. A videoscope uses a thin wire with a chip at the tip of the instrument to transmit images to a TV screen. The duodenoscope is inserted through the mouth, to the back of the throat, down the food pipe, through the stomach and into the first portion of the small intestine (duodenum). Once the papilla of Vater is identified, a small plastic catheter (cannula) is passed through an open channel of the duodenoscope into the papilla of Vater, and into the bile ducts and/or the pancreatic duct. Contrast material (dye) is then injected and x-rays are taken of the bile ducts and the pancreatic duct. The open channel also allows other instruments to be passed through it in order to perform biopsies, to insert plastic or metal tubing to relieve obstruction of bile ducts caused by cancer or scarring, and to perform incision by using electrocautery (electric heat). For further information on the anatomy and physiology of bile production (by the liver) and circulation, please visit the Gallstones article.

The liver is a large solid organ located beneath the right diaphragm. The liver produces bile, which is stored in the gallbladder (a small sac located beneath the liver). After meals, the gallbladder contracts and empties the bile through the cystic duct, into the bile ducts, through the papilla of Vater, and into the intestine to help with digestion. The pancreas is located behind the stomach. It also produces digestive juice which drains through the pancreatic duct into the papilla of Vater, and into the intestine.

What kind of preparation is required?

For the best possible examination, the stomach must be empty. The patient should not eat anything after midnight on the evening preceding the exam. In case the procedure is performed early in the morning, no liquid should be taken. In case the examination is performed at noon time, a cup of tea, juice, milk, or coffee can be taken 4 hours earlier. Heart and blood pressure medications should always be taken with a small amount of water in the early morning. Since the procedure will require intravenous sedation, the patient needs to have a companion drive him/her home after the procedure.

What can be expected during and after the procedure?

The patient will be given medication through a vein to cause relaxation and sleepiness. The patient will be given some local anesthetic to decrease the gag reflex. Some physicians do not use local anesthetic and prefer to give the patients more intravenous medication for sedation. This also applies to those patients who have a history of allergy to Xylocaine, cannot tolerate the bitter taste of the local anesthetic, or the numbness sensation in the throat. While the patient is lying on the left side on the x-ray table, the intravenous medication is given and then the instrument inserted gently through the mouth into the duodenum. The instrument advances through the food pipe and not the air pipe. It does not interfere with the breathing and gagging is usually prevented or decreased by the medication.

When the patient is in semi-conscious state, he/she can still follow instructions to change the position on the x-rays table. Once the instrument has been advanced into the stomach, there is minimal discomfort except for the foreign body sensation in the throat. The procedure can last anywhere from fifteen minutes to one hour, depending on the skill of the physician and the anatomy or abnormalities in that area.

After the procedure, the patients should be observed in the recovery area until most of the effects from the medication have worn off. This usually takes one to two hours. The patient may feel bloated or slightly nauseated from the medication or the procedure. Very rarely a patient experiences vomiting and may belch or pass some gas through the rectum. Upon discharge, the patient should be driven home by his/her companion and is advised to stay home for the rest of the day. The patient can resume usual activity the next day. Even though the physician may explain to the patient or companion regarding the findings after the procedure, it is still necessary to call the physician the next day to ensure that the patient understands the results of the examination.

What are the reasons for the examination?

The liver, bile ducts, gallbladder, pancreas and the papilla of Vater can be involved in numerous diseases, causing myriad of symptoms. ERCP is used in diagnosing and treating the following conditions:

Gallstones in the bile duct

Blockage of the bile duct by stones, cancer, stricture or compression from adjacent organs

Jaundice (yellow coloring of the skin) due to obstruction of the bile duct, also causing darkening of the urine and light colored stool.

Persistent or recurrent upper abdominal pain which cannot be diagnosed by other tests

Unexplained loss of appetite and weight loss

Confirming the diagnosis of cancer of the pancreas or the bile duct, so that surgery or other treatment can be tailored.

Cancer of the bile ducts or pancreas

Pancreatitis (inflammation of the pancreas)

Infections of the bile ducts

What are the side effects and risks of the procedure?

ERCP is a highly specialized procedure which requires a lot of experience and skill. The procedure is quite safe and is associated with a very low risk when it is performed by experienced physicians. The success rate in performing this procedure varies from 70% to 95% depending on the experience of the physician. Complications can occur in approximately one to five percent depending on the skill of the physician and the underlying disorder. The most common complication is pancreatitis which is due to irritation of the pancreas and can occur even in very experienced physicians. This "injection" pancreatitis is usually treated in the hospital for one to two days. Another possible complication is infection. Other serious risks including perforation of the bowel, drug reactions, bleeding, depressed breathing, irregular heart beat or heart attack are extremely rare. In case of complication, patient needs to be hospitalized and surgery is rarely required.

A temporary, mild sore throat sometimes occurs after the exam. Serious risks with ERCP are relatively uncommon. One such risk is pancreatitis.  Because the pancreas and bile ducts lie close to each other, there is a chance the pancreas can become inflamed.  It is important to understand this risk before proceeding with an ERCP.  Other risks include bleeding, especially if an incision is necessary, perforation and infection.  These complications may require hospitalization and, rarely, surgery. 

It is important to tell your physician if you are pregnant or if you have had prior reactions to contrast agents.

In summary, ERCP is a rather simple outpatient examination that is performed with the patient sedated. The procedure provides significant information upon which specific treatment can be tailored. In certain cases, therapy can be performed at the same time through the duodenoscope, so that traditional open surgeries can be avoided. ERCP is currently the diagnostic and therapeutic procedure of choice in most patients for identifying and removing gallstones in the bile ducts.

Due to the mild sedation, the patient should not drive or operate machinery for six hours following the exam. For this reason, a driver should accompany the patient to the exam.

Endoscopic Retrograde Cholangio-Pancreatography at a Glance

ERCP is a diagnostic procedure to examine diseases of the liver, bile ducts and pancreas.

ERCP is performed under intravenous sedation, usually without general anesthesia.

ERCP is an uncomfortable but not painful procedure. There is a low incidence of complications.

ERCP can provide important information that cannot be obtained by other diagnostic examinations, e.g. abdominal ultrasound, CT scan, endoscopic ultrasonography (EUS), or MRI.

Frequently, therapeutic measures can be performed at the time of ERCP to remove stones in the bile ducts or to relieve obstructions of the bile ducts.

Equipment

The flexible endoscope is a remarkable piece of equipment that can be directed and moved around the many bends in the upper gastrointestinal tract. The endoscopes have a tiny, optically sensitive computer chip at the end. Electronic signals are then transmitted up the scope to the computer which then displays the image on a large video screen. An open channel in the scope allows other instruments to be passed through it to perform biopsies, inject solutions, make incisions or place stents

The Procedure

An ERCP uses x-ray and is performed in a room specially equipped for x-rays. The patient is positioned on his or her stomach or left side with the head turned to the right.  The patient is sedated and a piece of plastic placed in the mouth to keep the mouth open. The endoscope is then gently inserted into the upper esophagus. The patient breathes easily throughout the exam, with gagging rarely occurring. A thin tube is inserted through the endoscope to the main bile duct entering the duodenum. Dye is then injected into this bile duct and/or the pancreatic duct and x-ray films are taken. If a gallstone is found, steps may be taken to remove it. An incision can be made using electrocautery (electrical heat) to open the lower portion of the duct as it enters the duodenum. Additionally, it is possible to widen narrowed ducts and to place small tubing, called stents, in these areas to keep them open. The exam takes from 20 to 40 minutes, but could take up to an hour or more, depending on the complexity of the procedure, after which the patient is taken to the recovery area

Results

After the exam, the physician explains the results. If the effects of the sedatives are prolonged, the physician may suggest an appointment for a later date when the patient can fully understand the results

Benefits

An ERCP is performed primarily to identify and/or correct a problem in the bile ducts or pancreas. This means the test enables a diagnosis to be made upon which specific treatment can be given. If a gallstone is found during the exam, it can often be removed, eliminating the need for major surgery. If a blockage in the bile duct causes yellow jaundice or pain, it can be relieved.

Alternative Testing

ERCP is now largely a therapeutic procedure and reserved for situations where an abnormality is expected.  Alternatives include a special MRI of the bile ducts (MRCP), which enables inspection of the bile ducts without the risk of ERCP.  Special ultrasound tests (endoscopic ultrasound), CT-scan and nuclear medicine x-rays are also ways to evaluate the bile ducts and pancreas.  In addition, dye can be injected into the bile ducts by placing a needle through the skin and into the liver. Small tubing can then be threaded into the bile ducts. Study of the blood also can provide some indirect information about the ducts and pancreas.

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