Gastroenterology and Hepatology Board Review: Pearls of Wisdom, Third Edition
Section IX MISCELLANEOUS TOPICS
CHAPTER 62. Gastrointestinal and Pancreaticobiliary Endoscopy
Ivana Dzeletovic, MD and Rahul Pannala, MD
Describe approaches to palliation of jaundice due to malignant biliary obstruction.
Obstructive jaundice secondary to inoperable malignant biliary strictures can be palliated with endoscopic stent placement (self-expanding metal stents [SEMS] or plastic stents). Percutaneous transhepatic biliary drainage (PTBD) and surgical bypass are alternatives to endoscopic stenting.
Describe complications associated with biliary stents.
Stent occlusion from debris or tumor ingrowth, cholangitis, stent migration, and cystic duct obstruction leading to cholecystitis (typically with fully covered SEMS).
What is Bouveret’s syndrome?
It refers to gastric outlet obstruction caused by duodenal impaction by a large gallstone, which passes into the duodenal bulb via a cholecystogastric or cholecystoduodenal fistula. First-line treatment is endoscopic retrieval with or without mechanical lithotripsy.
True/False: Hot biopsy removal of diminutive polyps and treatment of angiectasia in the right colon is associated with a high incidence of bleeding.
True. Alternative means of polyp removal and lesion treatment are available and recommended instead of hot biopsy for lesions in the right colon.
Describe qualities of an optimal colonoscopy bowel preparation.
Convenient, safe, tolerable, and effective.
True/False: Serious electrolyte and renal complications have been reported in patients with certain risk factors (eg, heart failure, renal failure, liver failure) receiving oral sodium phosphate products for their colonoscopy bowel preparation.
True. As a result, the Food and Drug Administration (FDA) has required manufacturers of oral sodium phosphate products to include a black box warning regarding potential complications.
A 27-year-old man presents with vague epigastric discomfort and fatigue, and is noted to have conjunctival icterus. He denies any other gastrointestinal complaints. Liver tests demonstrate a cholestatic picture. An abdominal ultrasound is normal. An endoscopic retrograde cholangiopancreatography (ERCP) is subsequently done demonstrating the following. What is the diagnosis? What other noninvasive test could have been used to make the diagnosis? What other endoscopic test should be considered in this patient?
Primary sclerosing cholangitis (PSC), note the extensive stricturing of the intrahepatic ducts. Magnetic resonance cholangiopancreatography (MRCP). Colonoscopy should be considered to evaluate for underlying inflammatory bowel disease.
What are the established risk factors for cholangiocarcinoma?
PSC, Caroli’s disease, choledochal cysts, infection with hepatobiliary flukes, hepatolithiasis, and toxins (Thorotrast).
What imaging modalities are used to diagnose choledocholithiasis?
The initial study of choice is transabdominal ultrasound (TUS) because it is noninvasive, cheap, and readily available. However, its sensitivity is only 40%, mostly due to poor visibility of the distal common bile duct (CBD). Endosopic ultrasound (EUS) and MRCP have excellent sensitivity and specificity; EUS is more sensitive for sludge and stones < 6 mm. The use of EUS or MRCP in patients with low to intermediate pretest probability of choledocholithiasis guides patient selection for ERCP. While ERCP has sensitivity of > 90% and specificity of 100%, it is rarely used for diagnosis of choledocholithiasis due to its invasiveness and potential risks.
What clinical factors are highly predictive of the presence of a retained CBD stone?
Clear presence of a CBD stone on transabdominal US, ascending cholangitis, and total bilirubin greater than 4. A strong suspicion of retained CBD stone occurs with a dilated CBD to more than 6 mm or a serum bilirubin between 1.8 to 4 mg/dL, while a moderate suspicion occurs with elevated transaminases, age > 55, and gallstone pancreatitis.
What are the criteria for the diagnosis of type I sphincter of Oddi dysfunction?
• Abdominal pain associated with abnormal alanine aminotransferase (ALT) and aspartate aminotransferase (AST) more than two times upper limit of normal on at least two occasions
• Dilated CBD > 10 mm on US or 12 mm on ERCP
• Delayed drainage of contrast from the CBD after > 45 minutes in the supine position
What is Mirrizi’s syndrome?
It is a rare complication in which a stone impacted in the neck of the gallbladder or cystic duct extrinsically compresses the CBD with resulting proximal biliary obstruction.
What is recurrent pyogenic cholangitis (RPC)?
It is a syndrome characterized by recurrent bacterial cholangitis, intrahepatic stones, and biliary strictures that is usually seen in young patients of South East Asian descent. Cholangiocarcinoma and secondary biliary cirrhosis are long-term complications.
What are the sites of a postcholecystectomy bile leak and what is the treatment of choice?
Most likely sites are the cystic duct stump or a duct of Luschka. Treatment with ERCP and stent placement is successful in the majority of cases.
What noninvasive test is most useful in detecting postcholecystectomy bile leaks?
Hepatobiliary scintigraphy (hepatoiminodiacetic acid [HIDA] scan) is highly sensitive and specific.
What are the indications for preoperative ERCP prior to laparoscopic cholecystectomy?
Preoperative ERCP is indicated when there is concomitant cholangitis, persistent biliary pancreatitis, or in the setting of a large CBD stone (> 1 cm) or multiple CBD stones.
What are the most common complications of chronic pancreatitis?
In addition to endocrine and exocrine insufficiency, chronic pancreatitis may be complicated by pseudocyst formation, biliary stricture due to CBD obstruction, gastric outlet obstruction, pancreatic ascites/pleural effusion, splenic vein thrombosis with isolated gastric varices, and splenic artery pseudoaneurysm formation.
What is the role of endotherapy in patients with chronic pancreatitis?
The role of pancreatic endotherapy in chronic pancreatitis is usually limited to symptomatic patients with a dominant pancreatic duct stricture or an obstructing stone in the head of the pancreas. Surgical drainage (Peustow procedure) or resection (Whipple operation) offers more definitive and longer-lasting pain relief in chronic pancreatitis. The use of EUS-guided celiac plexus block for the management of chronic pain is controversial given its generally poor efficacy.
What are the indications for pancreatic pseudocyst drainage?
The traditional teaching requiring intervention if the pseudocyst is larger than 6 cm or last longer than 6 weeks is no longer recommended. Currently, a more conservative approach is suggested with serial imaging (ultrasound or CT every 3–6 months) followed by pseudocyst drainage only if the patient is symptomatic (eg, abdominal pain, gastric outlet obstruction) or if the pseudocyst is infected. Drainage may be achieved by endoscopic or surgical cystgastrostomy or cystduodenostomy or percutaneously depending on communication of the cyst with the main pancreatic duct.
What are the complications of endoscopic pseudocyst drainage?
Bleeding, which can be severe enough to require surgical intervention in 5% of cases, retroperitoneal perforation, and infection. Failure to achieve resolution occurs in 10%–35% of cases and recurrence in 6%–18%. EUS-guided pseudocyst drainage decreases risk of bleeding associated with endoscopic drainage. Treatment of an associated pancreatic duct leak with pancreatic duct stent placement decreases the risk of recurrence.
What are the risk factors for post-ERCP pancreatitis?
Patient factors: young age, female gender, suspected sphincter of Oddi dysfunction, and history of recurrent pancreatitis.
Procedural factors: difficult cannulation, precut sphincterotomy, pancreatic contrast injection, and pancreatic duct sphincterotomy.
What are the proven measures to decrease the risk of post-ERCP pancreatitis?
In high-risk patients, placement of a temporary pancreatic duct stent at the time of ERCP significantly decreases the risk of pancreatitis. Several pharmacologic measures have been tried but have not proven to be beneficial.
What are the potential complications of pancreatic duct stenting?
Early complications: pancreatitis, pain, pancreatic duct rupture, bleeding, guidewire fracture requiring surgical removal, and acute cholangitis.
Late complications: development of pancreatic duct changes resembling chronic pancreatitis.
What are the diagnostic criteria for autoimmune pancreatitis?
HISORt criteria: Histology, characteristic Imaging, Serology (elevated IgG4), other Organ involvement (biliary strictures, parotid/lacrimal gland involvement, mediastinal lymphadenopathy, retroperitoneal fibrosis), Response to steroid treatment.
What are the two most common sites of heterotopic pancreas (ie, pancreatic rest)?
Stomach (antrum) and duodenum.
What is hereditary pancreatitis?
It is a syndrome of recurrent acute pancreatitis. The most common cause is a mutation in the cationic trypsinogen gene (PRSS1) expressed in an autosomal dominant pattern. Patients with hereditary pancreatitis have a markedly higher lifetime risk of pancreatic cancer as compared to the general population.
What is annular pancreas?
It is a congenital anomaly in which a portion of the pancreas forms a thin band around the periampullary portion of the duodenum, leading to complete or partial duodenal obstruction. It is associated with trisomy 21, cardiac defects, intestinal malrotation, genitourinary anomalies, and tracheoesophageal fistula.
When is cholecystectomy indicated for gallbladder polyps?
Polyps that are 10–20 mm in size could be malignant (25%–77%). Laparoscopic cholecystectomy with removal of the entire connective tissue layer to expose the liver is recommended. Polyps larger than 20 mm are usually malignant and require preoperative staging with CT and EUS.
Name five causes of secondary sclerosing cholangitis.
Operative trauma and ischemia, chronic choledocholithiasis, cholangiocarcinoma, chronic pancreatitis, and toxins (absolute alcohol and formaldehyde).
How frequently do patients with hepatic artery aneurysms present with jaundice?
Hepatic artery aneurysms, which are situated close to the bile ducts, present with jaundice in 50% of cases. The classic triad of epigastric pain, hemobilia, and jaundice is present in 33% of cases.
When should hemobilia be suspected?
Hemobilia should be considered in patients with upper GI bleeding and a recent history of hepatic parenchymal or biliary tract injury, including percutaneous and transjugular liver biopsy, cholecystectomy, endoscopic biliary biopsies and stenting, transjugular intrahepatic portosystemic shunt (TIPS), angioembolization, and blunt abdominal trauma. Other causes include gallstones, cholecystitis, hepatic or bile duct tumors, and hepatic abscesses.
What are the indications for EUS?
Common indications for EUS include locoregional staging and tissue acquisition in luminal GI malignancies, pancreatico-biliary neoplasms, and subepithelial lesions. Other indications are evaluation for chronic pancreatitis, posterior mediastinal lesions, perianal disease, and therapeutic applications.
Describe the characteristic five layer pattern of the GI tract as seen on EUS.
1. Mucosal interface
2. Muscularis mucosa
4. Muscularis propria
Describe the tumor classification of the TNM staging system for esophageal cancer.
An EUS image of a distal esophageal exophytic mass is shown below. Using the TNM staging system, what is the T-stage?
The image demonstrates a hypoechoic mass lesion involving the entire circumference of the esophagus leading to loss of the five layer architecture. In addition, there is extension beyond the muscularis propria at 4 o’clock and 9 o’clock positions suggesting a T3 tumor.
A 67-year-old woman presents with painless jaundice and without other systemic complaints. CT scan demonstrates a possible mass in the head of the pancreas. EUS demonstrates the following image. What is the next diagnostic test of choice?
Note the hypoechoic mass in the head of the pancreas. Tissue diagnosis may be established through EUS-guided fine needle aspiration (FNA).
What is the layer of origin of the mass noted in the following EUS image? What is the most likely diagnosis?
Fourth layer (muscularis propria). Gastrointestinal stromal tumors (GISTs) typically arise from the fourth layer (muscularis propria) and are most commonly seen in the stomach. On EUS, they are usually hypoechoic, homogeneous lesions with well-defined margins. Spindle cell neoplasms (leiomyoma and neuroma) have a similar appearance. FNA or tru-cut biopsy with immunohistochemistry is helpful in distinguishing between these lesions.
What are the EUS characteristics of GISTs that predict malignant transformation?
Size > 4 cm, irregular margins, cystic spaces, and echogenic foci.
What is the characteristic immunohistochemical staining pattern for GISTs?
GISTs characteristically exhibit positive staining for cKIT/CD117 (tyrosine kinase), CD34, and DOG1. Staining for smooth muscle actin (SMA) is negative, a feature that helps to differentiate them from leiomyomas.
What is the characteristic EUS appearance of a lipoma?
Lipomas usually arise from the third layer (submucosa), appear hyperechoic (bright) and homogeneous on EUS, and have regular margins. A positive pillow-sign on routine endoscopy is highly suggestive of a lipoma.
What is the reported risk of pancreatitis after EUS-FNA of pancreas?
What are EUS characteristics that suggest malignant transformation in pancreatic cysts?
Increase in cyst size over time, thick wall, mural nodularity, or the presence of a solid component within the cyst.
What is the most appropriate maneuver when a “white out” or “red out” occurs during colonoscopy?
Withdraw the colonoscope until the lumen comes into view.
How is cyst fluid analysis helpful in the evaluation of pancreatic cystic lesions?
EUS-FNA is usually used to acquire cyst fluid for chemical and cytological analysis. An elevated carcinoembryonic antigen (CEA) level (> 200 mg/dL) is more indicative of a mucinous cyst. Elevated cyst fluid amylase level is suggestive of a pseudocyst. Cytology can help in the evaluation of dysplasia within the cyst but sensitivity is limited. EUS-FNA of the cyst wall can also be helpful in evaluating suspected malignancy.
How is EUS helpful in the staging of rectal cancer?
EUS is indicated for locoregional staging of rectal cancer and for selection of patients who would benefit from neoadjuvant treatment (ie, patients with T3 or higher stage and those with nodal involvement [N1 or higher]). Both EUS and MRI are helpful in defining the extent of invasion into adjacent structures.
An otherwise healthy 73-year-old man presents for open-access colonoscopy due to the recent development of bright red blood per rectum. A rectal lesion shown in the figure is found. What is the likely diagnosis? Subsequent EUS of the lesion is done and demonstrates the finding shown in the figure below. What is the T-stage of the tumor?
Figure 62-5 For Figure 62-5A, see also color plate.
The endoscopic image shows a lesion highly suspicious for malignancy, which was subsequently proven following biopsies. The EUS image shows an eccentric mass lesion with involvement of the muscularis propria consistent with a T2 lesion. (see Figure 62-5A)
What are the durations of actions of antiplatelet agents and anticoagulants?
True/False: You should stop warfarin for low-risk endoscopic procedures.
False. Low-risk procedures include diagnostic endoscopy including biopsy, ERCP without sphincterotomy, EUS without FNA, diagnostic balloon-assisted enteroscopy, capsule endoscopy, and enteral stent deployment without dilation.
What are the high-risk conditions associated with thromboembolic complications that require bridging therapy?
Atrial fibrillation associated with valvular heart disease, prosthetic valves, active congestive heart failure, left ventricular ejection fraction < 35%, history of a thromboembolic event, hypertension, diabetes, age > 75 years, mechanical valve in the mitral valve position, mechanical valve in any position with history of thromboembolic event, recently placed coronary stent (< 1 year), and acute coronary syndrome.
What are low-risk conditions that do not require bridging therapy?
Uncomplicated or paroxysmal atrial fibrillation, bioprosthetic valve, mechanical valve in the aortic position, and deep vein thrombosis.
Name the high-risk procedures that require stopping both antiplatelet and anticoagulation therapy?
Polypectomy, biliary or pancreatic sphincterotomy, pneumatic or bougie dilation, percutaneous endoscopic gastrostomy placement, therapeutic balloon-assisted enteroscopy, EUS with FNA, tumor ablation by any technique, cystogastrostomy, and treatment of varices.
Which endoscopic procedures require antibiotic prophylaxis?
ERCP with anticipated incomplete drainage of bile duct obstruction, ERCP for sterile pancreatic fluid collection (pseudocyst, necrosis), which communicates with pancreatic duct, transmural drainage of sterile pancreatic fluid collection, EUS-FNA for cystic lesions along GI tract or in the pancreas, PEG tube placement, cirrhosis with acute GI bleed.
What is the rebleed rate of peptic ulcers with 1) active bleeding, 2) nonbleeding visible vessel, 3) adherent clot, and 4) pigmented spot?
55%–90%, 40%–50%, 10%–36%, and 7%–10%, respectively.
What medications are preferred for procedural sedation during pregnancy?
Meperidine (category B) alone is preferred but midazolam (category D) can be used as needed. Propofol (category B) can be used for deep sedation.
What medication is preferred for procedural sedation during breastfeeding?
Fentanyl has the lowest breast milk concentrations of the medications typically used. Infants should not be breastfed for at least 4 hours after maternal midazolam or propofol administration.
What are the indications for diagnostic balloon-assisted enteroscopy?
Evaluation of obscure GI bleed, suspected nonsteroidal anti-inflammatory drug (NSAID)-induced injury, suspected or established small bowel Crohn’s disease, refractory celiac disease, evaluation and tattooing of small bowel malignancies or other abnormal findings on imaging studies, detection of polyps in patients with polyposis syndromes, assistance with difficult and/or previously incomplete colonoscopies, and examination of the excluded stomach in patients who have undergone Roux-en-Y gastric bypass.
What are the therapeutic applications of balloon-assisted enteroscopy?
Treatment of GI bleeding, small bowel polypectomy, stricture dilation, stenting of small bowel obstructions, foreign body retrieval, endoscopic mucosal resection (EMR), and placement of direct percutaneous jejunostomy.
What are potential complications of balloon-assisted enteroscopy?
Pancreatitis, perforation, bleeding, and aspiration pneumonia. The overall complication rate is 1.2%–1.6%.
True/False: Moderate sedation (conscious sedation) refers to drug-induced depression of consciousness during which patients 1) cannot be easily aroused but respond purposefully following repeated or painful stimulation, 2) may have impaired ability to independently maintain ventilatory function, and 3) may require assistance in maintaining a patent airway.
False. The preceding is correct for deep sedation not moderate sedation, which is defined as a drug-induced depression of consciousness during which patients 1) respond purposefully to verbal commands, either alone or accompanied by light tactile stimulation, 2) do not require interventions to maintain a patent airway, and 3) maintain adequate spontaneous ventilation.
True/False: Capnography is recommended for all patients undergoing moderate (conscious) sedation.
False. Capnography is a noninvasive technique that measures carbon dioxide in exhaled breath and is more sensitive than direct visual observation or pulse oximetry for detecting hypoventilation. The American Society of Anesthesiologists (ASA) currently recommends that capnography be considered for patients receiving deep sedation and for patients whose ventilation cannot be observed directly during moderate sedation. It is not yet recommended for routine use during endoscopy.
True/False: The patency capsule is used to assure small bowel patency before video capsule endoscopy (VCE) and can also be used as a diagnostic test for suspected small bowel strictures that cannot be identified by standard radiographic means.
True. The patency capsule does not have any image acquisition capability.
True/False: Incomplete transit of the VCE capsule during its recording time occurs in approximately 33% of procedures
False. It occurs in < 20% and is of no clinical consequence, other than resulting in an incomplete examination of the small bowel.
Topical anesthetics for upper endoscopy should be avoided in patients with glucose-6-phosphate-dehydrogenase (G6PD) deficiency.
True. Topical anesthetics have been associated with methemoglobinemia in these patients.
True/False: Bougie esophageal dilation and pneumatic balloon dilation are equally effective in the treatment of achalasia.
False. The more forceful pneumatic dilation is necessary.
True/False: The endpoint of an esophageal dilation should be a lumen diameter of 13 mm.
False. Although there is no consensus, an endpoint of 18 mm is often chosen for most benign causes of esophageal strictures as it usually allows ingestion of a regular diet. Certainly, in some complex strictures (eg, radiation, caustic), a lesser diameter may be more appropriate.
What is the rule of 3’s?
The rule of 3’s pertains to esophageal dilation using bougie dilators whereby, once mild resistance is felt, continued dilation should only continue to a maximum of three additional dilator sizes (ie, 3 mm increase in diameter) during a single session.
What are some quality indicators for the performance of colonoscopy?
Cecal intubation rate, polyp and adenoma detection rates, photodocumentation of the cecum, documentation of the quality of the bowel preparation, retroflexion in the rectum, and complication rate.
True/False: Carbon dioxide (CO2) insufflation in deeply and moderately sedated patients during colonoscopy has been clearly shown to be superior to conventional air insufflation with regards to patient satisfaction.
False. A recent study reported that CO2 insufflation had no impact on patients’ satisfaction with the procedure or on their attitude to voluntary colorectal cancer screening; however, it was associated with significantly diminished abdominal pain after the procedure.
True/False: EMR is a suitable endoscopic alternative to surgical resection of mucosal and submucosal neoplastic lesions and intramucosal (T1) cancers.
True/False: Puckering or nonlifting of the lesion during injection of saline for a saline-assisted polypectomy suggests invasion of the muscularis propria.
True. Submucosal injection may decrease the incidence of perforation during saline-assisted polypectomy and EMR.
True/False: Complications with India ink injection, used for lesion localization, are common and may be related to the wide variety of organic and inorganic compounds contained in the ink solution such as carriers, stabilizers, binders, and fungicides.
False. Complications with India ink are rare, although the second part of the sentence is correct.
• • • SUGGESTED READINGS • • •
ASGE Practice Guideline on the management of low-molecular weight heparin and nonaspirin antiplatelet agents for endoscopic procedures. Gastrointest Endosc. 2005;61:189-194.
Cotton PB, Williams CB, Hawes RH, Saunders BP. Practical gastrointestinal endoscopy: The fundamentals. 6th ed. Hoboken, NJ: Wiley-Blackwell; 2008.
Baron TH, Kozarek RA, Carr-Locke D, eds. ERCP. 1st ed. Philadelphia, PA: WB Saunders Co; 2007.