Oesophago-Gastro-Duodenoscopy (OGDS): Role in Diagnosis and Treatment

OGDS (also called upper GI endoscopy or EGD) is a flexible fibre-optic or video endoscope passed through the mouth to directly visualise the oesophagus, stomach, and first part of the duodenum. It is both the most powerful diagnostic tool and an increasingly effective therapeutic instrument for upper GI pathology. The following covers its role across five major conditions, with each point attributed to its source.

Upper gastrointestinal haemorrhage carries an in-hospital mortality of 5-10%, rising to 33% when bleeding is first observed in already-hospitalised patients. The most common causes are peptic ulcer (60% of cases), erosions (26%), Mallory-Weiss tear (4%), and oesophageal varices (4%) (Table 67.4). The text is explicit that "upper gastrointestinal endoscopy should be carried out by an experienced operator as soon as practicable after the patient has been stabilised." In mild bleeding, endoscopy may wait until the following morning; in severe bleeding it should be performed immediately. The Rockall score (Table 67.5) is used pre- and post-endoscopy to stratify risk of rebleeding and death - it incorporates endoscopic findings (blood, adherent clot, visible or spurting vessel) alongside age, shock status, comorbidities, and diagnosis.

In all high-risk patients, upper endoscopy should be performed within 12 hours of admission, after resuscitation and correction of coagulopathy. "Endoscopic hemostasis should be considered in most high-risk patients with acute upper GI bleeding." Upper GI barium studies are contraindicated in acute UGIB because they interfere with subsequent endoscopy, angiography, or surgery (Table 98.1).

When deemed high risk, the management algorithm directs: "Perform upper endoscopy within 12 hours, after resuscitation and correction of coagulopathy." Most high-risk patients can be managed without operation if endoscopic haemotherapy and medical management are effective. Arteriography is occasionally helpful when endoscopy fails.

"Diagnosis can normally be made endoscopically, although occasionally the nature of the blood loss precludes accurately identifying the lesion. However, the more experienced the endoscopist, the less likely this is to be a problem." (p.1187-1188). In gastric outlet obstruction secondary to peptic ulceration, the stomach must first be emptied then investigated with endoscopy and contrast radiology. "Biopsy of the area around the pylorus is essential to exclude malignancy."

The Forrest Classification, applied at endoscopy, is the primary tool for predicting rebleeding risk and guiding management:

In patients where blood obscures the source, a second endoscopy may be required, but "routine second-look endoscopy is not recommended." For bleeding duodenal ulcers, the gastroduodenal artery is the most common source of major bleeding, and preoperative endoscopy identifies this site. For bleeding gastric ulcers, "excision or biopsy of the ulcer is important because 4% to 5% of benign-appearing ulcers are malignant ulcers."

"Therapeutic endoscopy can achieve haemostasis in approximately 70% of cases, with the best evidence supporting a combination of adrenaline injection with heater probe and/or clips." Patients with a visible vessel in the ulcer base, a spurting vessel, or a clot in the base are likely to require further or surgical treatment. Patients requiring more than six units of blood generally need surgical treatment. Where endoscopy fails, transcatheter embolisation is a valuable alternative before considering surgery. In gastric outlet obstruction from peptic ulcer, "endoscopic treatment with balloon dilatation may be most useful in early cases and may have to be repeated several times."

For bleeding duodenal ulcers failing endoscopic management, an anterior longitudinal duodenotomy is performed. The gastroduodenal artery is ligated with figure-of-eight sutures at the top and bottom of the ulcer crater, with a third U-stitch to control transverse pancreatic branches. The incision is then closed as a Heineke-Mikulicz pyloroplasty, classically with truncal vagotomy. For bleeding gastric ulcers, primary goal is haemorrhage control: wedge resection and primary closure for most greater curvature and antral ulcers; distal gastrectomy (Billroth I or II or Roux-en-Y) for distal lesser curvature ulcers near the incisura.

When a patient is deemed high risk on the basis of endoscopic findings (e.g., active bleeding, visible vessel, deep ulcer overlying the gastroduodenal artery, possible arterio-enteric fistula), the algorithm mandates: IV PPI, admission to ICU, surgical and gastroenterology consultation, and upper endoscopy within 12 hours. "Mucosal lesions can usually be controlled with endoscopic haemotherapy and medical management." Operation for bleeding ulcer is discussed in detail for those who fail endoscopic management.

Gastric erosions account for 9% of upper GI bleeds and oesophageal erosions a further 13% (Table 67.4). They are listed alongside peptic ulcers and Mallory-Weiss tears as the most common causes of haematemesis and melaena. The same principles of resuscitation followed by urgent endoscopy apply. "Stress ulceration" - a related entity of superficial mucosal erosions - commonly occurs in patients with major injury or illness; endoscopy is the means of both diagnosis and therapeutic intervention (injection, thermal coagulation, or clipping).

Erosions are listed among the causes of upper GI bleeding requiring endoscopic evaluation (Table 98.1). The endoscopic appearance helps determine which lesions require treatment beyond standard endoscopic therapy. When blood obscures the source, a second endoscopy may be required.

Gastric erosions and mucosal lesions, including stress gastritis, are identified at endoscopy. Endoscopic haemostasis is the primary approach; "mucosal lesions can usually be controlled with endoscopic haemotherapy and medical management." Arteriography is occasionally required when endoscopy fails to control bleeding from diffuse erosive disease.

Oesophageal varices are the most endoscopically dangerous of the common causes of upper GI bleeding. The Rockall score assigns specific points to variceal bleeding, indicating higher risk. Endoscopy allows direct visualisation of the varices, grading of their size and the presence of red wale signs (indicators of impending rupture), and confirmation of active bleeding.

Variceal bleeding is listed in Table 98.1 as a major cause of upper GI bleeding. Patients with known or suspected variceal bleeding should receive somatostatin analogue (octreotide 50 mcg IV bolus followed by 50 mcg/h infusion) and IV antibiotics before or concurrent with endoscopy. Balloon tamponade (Sengstaken-Blakemore tube or Minnesota tube) is described as a temporizing measure for uncontrollable haemorrhage likely from varices - tracheal intubation is mandatory if this is used.

"Fortunately, most bleeding from varices is oesophageal and is much more amenable to sclerotherapy, banding and balloon tamponade." Intravenous octreotide or terlipressin (a vasopressin analogue) reduces portal pressure and is of value in arresting haemorrhage. "Acute surgery on bleeding varices should be avoided, if possible, because of high operative mortality; it has been superseded in most centres by transjugular intrahepatic portosystemic shunt (TIPSS) insertion." Portal gastropathy - friable gastric mucosa exuding blood in the absence of visible varices - is also identified at endoscopy and treated with portal pressure reduction. For gastric varices specifically, "the gastric balloon of the Sengstaken-Blakemore tube can be used to arrest haemorrhage from the fundus of the stomach or GOJ." Sclerotherapy and banding of gastric varices are technically more difficult than for oesophageal varices.

In patients with oesophageal varices who fail medical/endoscopic management (10-20% of cases), "the next step should be rescue therapy in the form of emergent transjugular intrahepatic portosystemic shunt (TIPS) or surgical portocaval shunt creation. TIPS is typically preferred over surgery because operative mortality may be high in cirrhotic patients." Surgical management includes shunting procedures (portocaval, mesocaval, central splenorenal, large-diameter H-graft shunts) and non-shunting operations (oesophagogastric devascularisation, oesophageal transection, splenectomy - including the Sugiura procedure, formulated in 1973). "Overall, the literature showed a superiority of selective shunts in terms of controlling bleeding, maintaining portal flow, maintaining liver function, decreased postoperative encephalopathy, and overall survival, especially in non-alcoholics." For isolated gastric varices with splenic vein thrombosis, splenectomy is effective with an operative mortality of 5%. Liver transplantation should always be considered in the cirrhotic patient.

Endoscopic treatment with sclerotherapy or varix ligation is less successful for isolated gastric varices than for oesophageal varices but should be considered. Balloon-occluded retrograde transvenous obliteration (BRTO) via interventional radiology and TIPSS are the next steps for failed endoscopic treatment.

Mallory-Weiss tears constitute approximately 4% of upper GI bleeds. They present with haematemesis and are listed in the Rockall score as a low-risk diagnosis (score 0), reflecting their generally benign natural history. Endoscopy is the means of establishing this diagnosis.

Mallory-Weiss tears are mucosal lacerations at the gastroesophageal junction caused by forceful emesis, more commonly seen in alcoholic patients. "Upper endoscopy is both diagnostic of Mallory-Weiss tears and therapeutic. Most patients with active bleeding can be treated with endoscopic methods, such as epinephrine injection, thermal coagulation, endoscopic band ligation, or endoscopic hemoclipping." Angiographic transarterial embolisation may be useful in patients with persistent or recurrent bleeding after endoscopy.

"The Mallory-Weiss lesion is a longitudinal tear in the mucosa of the GE junction. It is presumably caused by forceful vomiting and/or retching, and it is commonly seen in alcoholics. It presents with upper GI bleeding, often with haematemesis. Endoscopy confirms the diagnosis and may be useful in controlling the bleeding, but 90% of patients stop bleeding spontaneously."

Initial management is PPI initiation and antiemetics. Endoscopic methods (epinephrine injection, thermal coagulation, band ligation, hemoclipping) treat most cases. Surgery is rarely necessary and is considered only after failure of endoscopic and angiographic procedures. When required: "Laparoscopic or open oversewing of the tear under endoscopic guidance has been performed with excellent results."

Other options after failed endoscopy include balloon tamponade, angiographic embolisation, selective or systemic vasopressin infusion, and operation. Surgical treatment consists of oversewing the bleeding lesion through a long gastrotomy.

"The diagnosis of oesophageal cancer is made by endoscopy with confirmation by biopsy. Tissue diagnosis is mandatory to determine the histologic subtype and for molecular characterization." A barium oesophagram may demonstrate irregular narrowing, ulceration, or an asymmetric bulge, but "endoscopy should be performed in any patient presenting with dysphagia, even if oesophagram suggests a motility disorder."

"Oesophageal cancers appear as friable, ulcerated masses or as strictures, but the endoscopic appearance can vary. Early-stage tumours may appear as ulcerations, small nodules, or even flat mucosal irregularities. In many cases, the initial endoscopist may not recognise the presence of cancer, and a single biopsy may not be diagnostic. Therefore, multiple biopsies should be performed for any suspicious lesions to attain accurate tissue diagnosis."

During endoscopy it is essential to document:

Adenocarcinomas at the EGJ whose epicentre is no more than 2 cm into the gastric cardia are staged as oesophageal cancers; those with epicentres more than 2 cm below the EGJ are staged as gastric cancers.

Clinical staging uses a combination of EGD with biopsy, endoscopic ultrasound (EUS) with or without fine-needle aspiration (EUS-FNA), endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD), CT, and PET-CT. EUS specifically provides the most reliable method of determining depth of cancer invasion (T staging) and nodal involvement.

"Oesophageal cancer generally presents with dysphagia, although increasing numbers of relatively asymptomatic patients are now identified on surveillance endoscopy, or present with non-specific upper GI symptoms and undergo screening endoscopy." Rarely, severe bleeding from erosion into the aorta or pulmonary vessels occurs.

"For years, clinical staging, contrast radiography, endoscopy, and CT scanning formed the backbone of oesophageal cancer staging. More recently, preoperative decision making is guided by endoscopic ultrasonography and PET scanning." EUS provides the most reliable method of determining depth of cancer invasion. If a small focus of cancer is confined to the mucosa, "endoscopic mucosal resection (EMR) is a preferable option." If the tumour invades into the submucosa without visible lymph node involvement, oesophagectomy with lymph node dissection is indicated (20-25% risk of positive nodes in submucosal disease).

Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) are established treatment options for early-stage oesophageal cancer, Barrett's oesophagus, early gastric cancer, duodenal lesions, and colon and rectal polyps and cancers. "EMR uses a variety of suction, lift, and underwater techniques" for resection of superficial lesions.

Patients with tumours confined to the mucosa (T1a) are candidates for EMR. Surveillance endoscopy is used to identify disease recurrence following treatment.

In advanced, unresectable disease, endoscopy plays a key palliative role. Oesophageal stenting (self-expanding metal stents placed endoscopically) is used to relieve dysphagia. Tumour characteristics, degree of obstruction, presence of tracheo-oesophageal fistula, and expected survival all inform the choice of palliation.

Oesophageal dilation, stent placement, and laser therapy are endoscopic palliative measures for advanced oesophageal cancer. Cardiopulmonary assessment and nutritional status (albumin <3.5 g/dL, weight loss >20 lb) are weighed when determining whether curative resection is feasible vs. palliation appropriate.