Endoscopy of the upper and lower gastrointestinal tract

CHAPTER 20 Endoscopy of the upper and lower gastrointestinal tract






Indications


Upper gastrointestinal tract (GI) endoscopy and lower gastrointestinal tract endoscopy means direct inspection of the esophagus, stomach, duodenum, small intestines and the colon using a flexible fiberoptic endoscope. A gastroscopy (aka esophago-gastroduodenoscopy or OGD) refers to the examination of the esophagus, stomach and duodenum, whereas enteroscopy refers to examination of the small intestines. Full examination of the colon to the cecum is known as colonoscopy, examination of just the left colon to the splenic flexure is known as flexible sigmoidoscopy.


Endoscopy and fluoroscopy can be used to investigate the GI tract, but there are advantages to endoscopy which may be taken into account when a clinician decides which test to request:







Both endoscopy and fluoroscopy complement each other in the assessment of the GI tract. Gastroscopy is the investigation of choice for upper GI investigation and colonoscopy often follows radiological investigation. It could be argued that endoscopy would be preferable in every case as the patient could have both diagnosis and treatment in a single test. However, in many hospitals, endoscopy services are overstretched and a barium enema is often a good first line test in selected patients. Endoscopy also carries a risk of morbidity and even mortality as discussed below.



Types of endoscopy





Colorectal endoscopy


Visualization of the lower bowel can be performed using a rigid or flexible endoscope. Rigid sigmoidoscopy and proctoscopy usually occur in the outpatient clinic. The Association of Coloproctology of Great Britain and Ireland recommends that a patient referred for barium enema should have had at least a rigid sigmoidoscopy prior to referral (Guidelines for Management of Colorectal Cancer, 2007). The reason for this is that lesions very low down in the rectum may be missed on barium enema but seen on proctoscopy or rigid sigmoidoscopy. A rigid examination is especially important in patients presenting with bright red rectal bleeding as common pathologies such as distal proctitis or hemorrhoids may not be demonstrated on barium enema.


Proctoscopy involves inserting a rigid instrument approximately 10 cm long into the distal rectum. No air insufflation is used but there is a light source attached giving good visualization of piles/mucosal prolapse but only limited views of the lower rectum. For full visualization of the rectum a rigid sigmoidoscope is used. This is a 25 cm long rigid tube connected to a light source with air insufflation to give a good luminal view. The word ‘sigmoidoscopy’ is actually a misnomer as it is difficult to negotiate the various mucosal folds required to enter the sigmoid with a rigid instrument. However, it is useful diagnostic tool and may influence the investigation subsequently chosen. For example, if a polyp is seen at rigid sigmoidoscopy, it is preferable to go straight to colonoscopy where a therapeutic procedure can be performed at the same time. Likewise, if distal colitis is seen, colonoscopy may be more appropriate than barium enema to determine extent and get a tissue diagnosis.


Flexible endoscopic examinations of the lower GI tract fall into two tests – flexible sigmoidoscopy and colonoscopy. Previously, there were separate endoscopes for each test but, in practice, a colonoscope is used for both. A colonoscope is a 160 cm long fiberoptic telescope that is inserted via the anus.


For a flexible sigmoidoscopy

Dec 26, 2015 | Posted by in GASTROINTESTINAL IMAGING | Comments Off on Endoscopy of the upper and lower gastrointestinal tract
Premium Wordpress Themes by UFO Themes