section name header

Info


A. Types of GI Endoscopy navigator

  1. Upper
  2. Pancreatic and Biliary
  3. Sigmoidoscopy
  4. Colonoscopy
  5. Anoscopy

B. Upper Endoscopy [1] navigator

  1. Standard diagnostic endoscopes have 9mm and therapeutic endoscopes 11mm diameters
  2. The use of these endoscopes requires sedation and adds risk and cost to procedures
  3. New ultrathin endoscopes (<6mm) are being developed and may not require sedation
  4. Indications
    1. Acute: diagnosis and treatment of upper gastrointestinal (GI) bleeding
    2. Chronic: evaluation of non-malignant and malignant upper GI lesions
  5. Endoscopy in Upper GI Bleeding [2]
    1. Endoscopy is best modality for diagnosis
    2. Also useful in most instances for treatment
    3. Endoscopic hemostasis for aptients with high-risk endoscopic lesions
    4. In high risk patients, combination of injection and thermal coagulation
    5. Endoscopic clips also appear promising for hemostasis
    6. Routine second look endoscopy is not recommended
  6. Nonvariceal Bleeding of the upper GI Tract
    1. About 50% of cases are bleeding from peptic ulcer
    2. Mallory-Weiss Tears and vascular malformations (AVMs) are also found
    3. Endoscopy used both diagnostically and therapeutically
    4. Thermocoagulation of bleeding sources leads to hemostasis in >90% of cases
    5. Electrocoagulation, injection therapy, laser, hemoclipping, and ligation also used
    6. Recurrence of bleeding from ulcers is <20%
    7. Endoscopic retreatment is successful in >90% of cases and is superior to surgery
  7. Variceal Bleeding
    1. Most severe complication of portal hypertension
    2. Bleeding occurs in about 35% of patients with esophageal varices
    3. Endoscopic band ligation is the treatment of choice for esophageal varices
    4. Band ligation is superior to endoscopic sclerotherapy
    5. Band ligation may also be superior to medical therapy for primary prevention of bleeding in patients with large esophageal varices
  8. Non-malignant Upper GI Lesions
    1. Barrett's Esophagus is the most common - surveillance is recommended
    2. Endoscopic treatment of Barrett's followed by acid control can reverse metaplasia
    3. Achalasia is effectively treated endoscopically with botulinum toxin
  9. Malignant Upper GI Lesions
    1. Esophageal carcinoma - diagnosis, dilation of strictures, stents, photodynamic therapy
    2. Gastric carcinoma - endoscopic mucosal resection for early stage lesions
    3. Expandable stents called endoprostheses can be implanted for esophageal or gastric lesions [3]
  10. Small Intestinal Endoscopy
    1. Push endoscopy - long scope is pushed beyond the ligament of Treitz but cannot visualize the entire small intestine; therapeutic potential
    2. Intraoperative Endoscopy - can visualize entire small intestine through laparotomy
    3. Sonde (passive) Endoscopy - long flexible scope allowed to move along intestine passively; no therapeutic potential

C. Pancreatic and Biliary Endoscopy [4] navigator

  1. Duodenoscopes are used for ERCP
    1. Side viewing scopes - imaging along lateral aspect (walls)
    2. Capacity to control direction of catheters as gthey exit the instrument channel
  2. Entrance to pancreatic and bile ducts cannulated with special catheters
  3. These catheters are placed through the instrument channel
  4. Endosconoscope
    1. Ultrasound can be obtained with ERCP by using an ultrasound transducer tip
    2. Transducer tip may be oriented in radial or linear fashion
    3. Linear array endosonoscopes have capacity to direct needle aspiration biopsies
  5. Small-Diameter ERCP
    1. Cannulate and drain the pancreatic-biliary tree (small, tapered catheters)
    2. Implant stents - plastic or metal devices
  6. Sphincterotomy
    1. Performed to open the biliary sphincter
    2. Small cetheter for cutting called a sphincterotome
    3. May be required for allowing passage of stones, particularly larger ones
    4. Some concern about fibrosis (healing) of scar and exposure of duodenum to bile acids
  7. Indications for Biliary / Pancreatic Endoscopy
    1. Primary method for evaluation / treatment of acute bile duct obstruction (cholangitis)
    2. Primary method for evaluation / treatment of acute pancreatic duct obstruction
    3. Choledocholithiasis - removal of common bile duct stone with basket, balloon
    4. Acute cholangitis - prompt stone removal and biliary drainage required
    5. Benign or malignant biliary strictures
    6. Biopsy and diagnosis of ductal obstruction including malignant tumors
    7. Evaluation and treatment of acute and chronic pancreatitis
    8. Benign (such as islet cell) and malignant pancreatic tumors
  8. Techniques
    1. Benign biliary strictures can be dilated and/or stented
    2. Biliary leaks can be stented
    3. Malignant biliary or pancreatic duct strictures are stented with plastic or metal stents
    4. Plastic stents are temporary and more easily occluded
    5. Metal expandable stents are employed for cancerous obstruction [3]
    6. Manometry of Sphincter of Oddi for suspected sphincter dysfunction can be performed
  9. Complications
    1. Unlike most other endoscopies, ERCP has significant complication rate
    2. Pancreatitis and small retroperitoneal perforations occur in 5-10% of patients
    3. These complications can cause significant morbidity and mortality
    4. Prophylactic use of gabexate, a protease inhibitor, reduces this complication rate
    5. Bleeding or cholangitis can also occur, but these are rarely life-threatening

D. Sigmoidoscopy navigator

  1. Rigid and flexible sigmoidoscopes are available
  2. Flexible sigmoidoscopy is recommended for colorectal cancer screening
    1. Flexible visualizes 40-60cm of distal colon
    2. Rigid visualizes only 25cm
    3. ~50% of all colorectal cancers are in the distal 50cm of large intestine
  3. May be performed in office practice
  4. Not as sensitive for detection of colonic polyps of maligancices as colonoscopy
  5. Generally well tolerated by patients with minimal discomfort
  6. Rectal biopsies for ulcerative colitis and other diseases is possible

E. Colonoscopy navigator

  1. Allows visualization of interior of entire length of colon from anus to cecum
  2. Main Utility
    1. Colon cancer screening
    2. Identification and removal of (premalignant) polyps
    3. Visualization and biopsy of colonic lesions
    4. Optical (standard) colonoscopy has sensitivity of >85% for colonic polyps and can miss even >10mm adenomas, usually located behind a fold or near anal verge [7]
    5. Evaluation of lower gastrointestinal bleeding (even in young persons [5])
    6. Followup after barium enema or sigmoidoscopy
  3. Procedure Overview
    1. Liquid diet for 2 days
    2. Oral preperative regimen (see below)
    3. Tap water enemas the morning of the procedures
    4. Alternative to laxative/enema is nonabsorbab le electrolyte solution
    5. Patient is sedated with intravenous agents usually including benzodiazepine
  4. Oral Preperative Solutions [8]
    1. PEG Solution (Colyte®, GoLytely®, NuLytely®, TriLyte®): 240mL (8 ounces) every 10 minutes to 4 liters (L)
    2. PEG 240mL q10 minutes to 2L only + bisacodyl tablet 1 to 6 hours before (HalfLytely®)
    3. Sodium Phosphate (Fleet Phospho-Soda®): 30-45 mL (2-3 tbsp) taken with at least 8 ounces of liquid, followed by 16 ounces of liquid; second dose >3 hours prior to endoscopy
    4. Sodium Phosphate Tablets (Visicol®): 3 tablets every 15 minutes with 8 ounces clear liquid (last dose is 2 tablets) on the evening before procedure
  5. Complications
    1. Hemorrhage and perforation, but these are rare
    2. Overall morbidity 0.5-1.0%; with polypectomy ~1.5%
    3. Mortality 0.02%
    4. Colonoscopy should be avoided during active colitiis
    5. Prior radiation or diverticulitis makes procedure more difficult and hazardous

F. Anoscopy [6]navigator

  1. Ive's Slotted anoscope is preferred
  2. Procedure
    1. Lubricant applied to entire (two piece) unit
    2. Insert gently
    3. Remove introducer and visualize 25% of mucosa at a time
    4. Slowly withdraw anoscope
    5. Rotate 90° and reinsert (4 insertions total)
  3. Preparation with enema is not generally required

References navigator

  1. Van Dam J and Brugge WR. 1999. NEJM. 341(23):1738 abstract
  2. Barkun A, Bardou M, Marshall JK. 2003. Ann Intern Med. 139(10):843 abstract
  3. Baron TD. 2001. NEJM. 344(22):1680
  4. Brugge WR and Van Dam J. 1999. NEJM. 341(24):1808 abstract
  5. Lewis JD, Brown A, Localio AR, Schwartz JS. 2002. Ann Intern Med. 136(2):99 abstract
  6. Pfenninger JL and Zainea GG. 2001. Am Fam Phys. 63(12):2391 abstract
  7. Pickhardt PJ, Nugent PA, Mysliwiec PA, et al. 2004. Ann Intern Med. 141(5):352 abstract
  8. Colonoscopy Preparations. 2005. Med Let. 4791212):53