Oesophagogastroduodenoscopy

Conventional oesophagogastroduodenoscopy (OGD) is an indispensable tool in the evaluation of the upper digestive tract (Rossi A, Bersani G, Ricci G, et al., 2002) , (Kim CY, O`Rourke RW, Chang EY, Jobe BA, 2006) . It affords an excellent view of mucosal surfaces of the oesophagus, stomach, duodenal bulb and first portion of the duodenum (American Society for Gastrointestinal Endoscopy, 2000) .

Upper endoscopy is usually performed with a flexible scope with conscious sedation, however, most patients tolerate the procedure with only topical anaesthesia of the oropharynx using lidocaine spray (Wrightson WR (ed), 2006) , (Not known) . Some patients may even need a general anaesthesia, if they are very anxious or agitated. The upper digestive tract must be empty for the procedure, so it is necessary NOT to eat or drink for at least 6–12 hours before the exam. Informed consent should be obtained before the procedure, and patients need also to inquire about taking their medications.

Practical tips

After you assemble the scope and light source, practice flexing the tip with the deflector lever. Note how far a certain control input will deflect the tip of the scope. Turn on the light source and view some external object. Note how only the portion of the object in the centre of the scope's field of view is seen; also note how close you must be to the object to bring it into focus.

ALWAYS advance the endoscope under direct vision, NOT blindly. If the scope does not want to pass or the patient complains of discomfort, you may be taking a false step with the instrument or bumping into an obstruction. Slowly withdraw a little bit or even remove the scope and try again (James DM (ed), 2001) .

Anatomy and technical aspects (Wrightson WR (ed), 2006) , (Van Dam J, Wong RCK, 2004) , (Not known)

• The oesophagus is a muscular tube that actively transports food from the mouth to the stomach in a co-ordinated fashion (i.e. by rhythmic contractions known as peristalsis). The proximal one-third of the oesophagus is primarily skeletal (striated) muscle, and the distal two-thirds consists of smooth muscle. The normal diameter is 15-20 mm, and the length of the oesophagus is 20-25 cm, spanning the cricopharyngeal muscle to the diaphragmatic hiatus (Fig. 1). Through the length of the oesophagus there are three areas of narrowing: 1. cricopharyngeal muscle (upper oesophageal sphincter), 2. aortic arch (24 cm), 3. lower oesophageal sphincter (40 cm). The entire oesophagus lacks a serosa and has an extensive lymphatic plexus. This is a partial explanation as to occult spread of cancers beyond the gross specimen.

enlarge | info

Fig. 1. Anatomy of the upper GI tract
[Colour drawing by Terese Winslow. Source: NCI Visuals Online, 2005]

• The patient lies on his/her left side with the head resting comfortably on a pillow. A mouth-guard is placed between the teeth, partly to protect the patient's teeth but more importantly to prevent the patient from biting on the very expensive endoscope. An OGD begins when the endoscope is passed through the incisor teeth, over the tongue and into the oropharynx. This is the most uncomfortable stage for the patient.
• Quick and gentle manipulation under vision guides the endoscope into the oesophagus to the level of the cricopharyngeal muscle, which helps form the upper oesophageal sphincter (UOS) (at 15 cm from the incisors). If the patient is asked to take a deliberate swallow, the receptive relaxation of the UOS (that follows the swallow) can allow passage of the endoscope. The endoscope is gradually advanced down the oesophagus making note of any pathology. The normal mucosal colour of the oesophageal squamous epithelium is pale pink. Often secondary peristaltic contractions can be observed, as the endoscope passes distally. Excessive insufflation of the stomach is avoided at this stage.

enlarge | info

Fig. 2. Oesophagoscopy

The endoscope is inserted through the mouth and into the oesophagus. Inset shows patient on table having an oesophagoscopy. [Colour drawing by Terese Winslow. Source: NCI Visuals Online, 2005]

• At 25-30 cm from the incisors, the aorta can be seen compressing the oesophagus and just distal to this an impression can be seen from the left main stem bronchus.
• In the distal oesophagus, there is a clear demarcation between the two types of mucosa, that often appears as a line, called the squamocolumnar junction or Z line. The Z line is normally located at the level of the lower oesophageal sphincter (LOS), is within the distal 2 cm of the oesophagus, and marks the transition from squamous to columnar mucosa. The distance from the incisors to the LOS is 40 cm.
• As the endoscope is passed into the stomach, the LOS opens spontaneously, allowing unimpeded passage into the stomach. Once the endoscope is passed into the stomach, the oesophageal exam is completed with retroflexion to examine the gastric cardia.
• The stomach is a J-shaped organ that lies in the left and central portion of the abdomen (Fig. 3). Its function is to act as a reservoir for ingested food. It also serves to break down foodstuffs mechanically. The stomach produces many digestive juices and acids that mix with food and commence the processes of digestion before these products are passed on into the duodenum.

enlarge | info

Fig. 3. Anatomy of the stomach

• There are five regions of the stomach that should be explored:
  1. the cardia, area surrounding the cardiac sphincter which controls movement of food from the oesophagus into the stomach (Fig. 5A),
  2. the fundus, upper expanded area adjacent to the cardiac region,
  3. the antrum, lower region of the stomach where it begins to narrow,
  4. the prepyloric, region just before or nearest the pylorus and the pylorus, the terminal region where the stomach joins the small intestine (Fig. 5D).
• The endoscope is quickly passed through the stomach and through the pylorus to examine the first and second parts of the duodenum (Fig. 4).

enlarge | info

Fig. 4. Gastroscopy

The endoscope is inserted through the mouth and oesophagus into the stomach to look for abnormal areas in these parts of the GI tract. Inset shows patient on table having an upper endoscopy. [Colour drawing by Terese Winslow. Source: NCI Visuals Online, 2005]

A.

enlarge | info

B.

enlarge | info

C.

enlarge | info

D.

enlarge | info

Fig. 5. Endoscopy images of normal stomach of a healthy 65-years old woman: the cardia (A), body (B), mucous surface (C), and the pylorus (D) (Permission of patient to publish this image was obtained.)

• The duodenum is the first part of the small intestine, into which the stomach, the gall bladder, and the pancreas empty their contents. The pylorus connects the duodenum with the stomach and contains the valve that regulates stomach emptying.
• Once the examination of the duodenum has been completed, the endoscope is withdrawn into the stomach and a more thorough examination is performed including a J-manoeuvre. This involves bending the tip of the scope so it resembles a 'J' shape in order to examine the fundus. Any additional procedures are performed at this stage.
• Small biopsies can be made with a pincer (biopsy forceps) which is passed through the scope and allows sampling of 1 to 3 mm pieces of tissue under direct vision. The intestinal mucosa heals quickly from such biopsies. Biopsy allows the pathologist to render an opinion on later histological examination of the biopsy tissue with light microscopy and/or immunohistochemistry. Biopsied material can also be tested on urease to identify Helicobacter pylori.
• The air in the stomach is aspirated before removing the endoscope. Still photographs can be made during the procedure and later shown to the patient to help explain any findings.

Specific indications for diagnostic OGD (American Society for Gastrointestinal Endoscopy, 2000) ,

1. Upper abdominal symptoms, which persist despite an appropriate trial of therapy
2. Upper abdominal symptoms associated with other symptoms or signs suggesting serious organic disease (e.g. anorexia and weight loss) or in patient over 45 years of age
3. Dysphagia or odynophagia:
   • Dysphagia is the term used to describe difficulty, but not necessarily pain, on swallowing. It is often described by patients as ‘food sticking’. The localisation of the hold-up may help to differentiate between an obstruction at the cricopharyngeal sphincter in the body of the oesophagus or at the lower end. The type of dysphagia is important. It may be dysphagia for solids or fluids, intermittent or progressive, precise or vague in its appreciation.
   • Odynophagia refers to pain on swallowing. Patients with reflux oesophagitis often feel burning retrosternal discomfort within a few seconds of swallowing hot beverages, citrus drinks or alcohol. It may be particularly severe in chemical injury of the oesophagus.
4. Oesophageal reflux symptoms, which are persistent or recurrent despite appropriate therapy
5. Persistent vomiting of unknown cause
6. Other diseases in which the presence of upper GI pathology might modify other planned management, e.g.
   • patients who have a history of ulcer or GI bleeding, and are scheduled for organ transplantation, long-term anticoagulation, or chronic non-steroidal anti-inflammatory drug (NSAID) therapy,
   • patients with cancer of the head and neck
7. Familial adenomatous polyposis syndromes
8. For confirmation and specific histological diagnosis of radiologically demonstrated lesions:
   • suspected neoplasm
   • gastric or oesophageal ulcer (Fig. 6)
   • upper GI tract stricture or obstruction (Fig. 7)

A.

enlarge | info

B.

enlarge | info

C.

enlarge | info

Fig. 6. Endoscopic images of ulcerative lesions: benign gastric ulcer (A), deep gastric ulcer in the gastric antrum (B), duodenal ulcer (C) (Permission of patients to publish these images was obtained.)

enlarge | info

Fig. 7. Endoscopic and radial endoscopic ultrasound (EUS) images of submucosal tumour in the mid-oesophagus. (Permission of patient to publish these images was obtained.)

9. Gastrointestinal bleeding:
   • in patients with active or recent bleeding
   • for presumed chronic blood loss and for iron deficiency anaemia when clinically an upper GI source is suggested or when colonoscopy is negative
10. When sampling of tissue or fluid is indicated
11. In patients with suspected portal hypertension to document or treat oesophageal varices
12. To assess acute injury after caustic ingestion
13. Surveillance for malignancy in patients with pre-malignant conditions (i.e. Barrett’s oesophagus - a metaplastic change in the lining mucosa of the oesophagus in response to chronic gastro-oesophageal reflux); in such cases sequential or periodic OGD may be indicated

Case study: A 61-year-old man with dyspepsia and weight loss (Burton C, 2004)

A 61-year-old male carpenter presented with ten months' history of dyspepsia. More recently he had developed epigastric pain and had lost four kilograms in weight because of anorexia. He was otherwise asymptomatic and in particular there was no history of nausea, vomiting, abdominal distension, melaena, haematemesis, diarrhoea, constipation, night sweats, or fevers. There was no past medical history of note, and he had a performance status of zero. His only medication was lansoprazole. He drank no alcohol and smoked 40 cigarettes/day. Examination was unremarkable. All blood tests, including full blood count, biochemistry, and lactate dehydrogenase, were normal.

The differential diagnosis in a patient with dyspepsia, epigastric pain, and weight loss is gastro-oesophageal reflux, gastritis, gallstones, peptic ulcer, oesophageal/gastric carcinoma, lymphoma, and inflammatory bowel disease.

The patient underwent an endoscopy which showed a 4–5-cm ulcer with rolled edges on the greater curve of the antrum of the stomach. Appearances were suggestive of a malignant lesion.

For full description and comments: see http://medicine.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pmed.0020154

Specific indications for therapeutic OGD (American Society for Gastrointestinal Endoscopy, 2000) , (Not known)

1. Treatment of bleeding lesions such as ulcers, tumours, vascular abnormalities (i.e. electrocoagulation, heater probe, laser photocoagulation or injection therapy, e.g. with adrenalin)
2. Banding or sclerotherapy of oesophageal varices (Fig. 8)
3. Removal of foreign bodies
4. Removal of selected polypoid lesions
5. Placement of feeding or drainage tubes (i.e. percutaneous endoscopic gastrostomy or jejunostomy)
6. Dilation of stenotic lesions (e.g. with transendoscopic balloon dilators or dilation systems employing guide wires)
7. Management of achalasia (e.g. botulinum toxin injection, balloon dilation)
8. Palliative treatment of stenosing neoplasms (e.g. photodynamic therapy, laser evaporation, multipolar electrocoagulation, stent placement, etc.) (Fig. 9)

enlarge | info

Fig. 8. Oesophageal varices after banding (posted in public domain with permission of patient)

enlarge | info

Fig. 9. Oesophageal stent.Cancer blocking the oesophagus is shown. Insets show enlarged area of cancer and a stent placed in the oesophagus to keep it open. [Colour drawing by Terese Winslow. Source: NCI Visuals Online, 2005]

Newer interventions include:

• Endoscopic trans-gastric laparoscopy
• Instillation of gastric balloons in bariatric surgery (i.e. surgical treatment of obesity)

Complications

The main risks are bleeding and perforation. The risk is increased when a biopsy or other intervention is performed.

Recently described, unsedated small-calibre upper endoscopy (SCE) is an emerging technology that represents an alternative to conventional OGD (Kim CY, O`Rourke RW, Chang EY, Jobe BA, 2006) . It enables transnasal evaluation of the upper GI tract in an unsedated patient.

The diameter of a small-calibre endoscope is 3-6 mm, depending on the manufacturer, therefore SCE is better tolerated and requires no sedation compared with the conventional OGD. Endoscopes with lengths from 65 cm to 110 cm allow examination of the naso-, oro-, and hypopharynx, oesophagus, stomach, and duodenum. A working port enables biopsy specimens of the mucosal surface to be obtained (Kim CY, O`Rourke RW, Chang EY, Jobe BA, 2006) .

This procedure can be performed in a wider range of settings, and can be incorporated into the office visit. Other potential advantages of SCE may include ability to perform direct laryngoscopy and to examine the nasopharynx, improved screening for oesophageal cancer, cost savings, improved physician efficiency, immediate patient feedback on endoscopic findings, and also less pre-procedure preparation and avoidance of sedation-related complications (Kim CY, O`Rourke RW, Chang EY, Jobe BA, 2006) .

The diagnostic applications of SCE include general diagnostic upper endoscopy, screening and surveillance of Barrett’s oesophagus, evaluation of acutely ill in-patients (who cannot tolerate narcotics and sedatives), intraoperative diagnostics or postoperative evaluation of the upper GI tract.

Therapeutic applications include the placement of nasoduodenal feeding tubes, oesophageal pH and impedance catheters (in patients with laryngopharyngeal reflux), and also in the sedated patients: oesophageal stricture dilation, and transnasal placement of a percutaneous endoscopic gastrostomy tube (Kim CY, O`Rourke RW, Chang EY, Jobe BA, 2006) .

Glossary

HES

Hemalun Eosine Safran (histology, French: Cell components revelation method)