Esophagogastroduodenoscopy: how it is performed and what it reveals

Esophagogastroduodenoscopy is an endoscopic examination of the esophagus, stomach, and duodenum using a flexible, thin instrument equipped with a video camera. This method allows for a detailed examination of the mucosa, targeted biopsies for morphological confirmation of a diagnosis, and, if necessary, immediate treatment: stopping bleeding, widening a stenosis, removing a polyp or early cancer. Unlike imaging techniques, endoscopy reveals not only the contours and thickness of the wall but also the surface pattern, vessels, and microstructure of the mucosa. This increases the accuracy of detecting inflammatory, precancerous, and early malignant changes. [1]

The key to a quality examination is a slow and systematic examination with photographic recording of reference zones, thorough cleaning of the mucosa of mucus and vesicles, and the use of visualization enhancement technologies. International professional societies emphasize that examination technique and preparation directly determine the diagnostic value of the procedure. [2]

The method is considered the standard for confirming many diseases: reflux esophagitis, peptic ulcer disease, chronic gastritis, Helicobacter pylori infection, eosinophilic esophagitis, celiac disease, etc. Endoscopy also determines the stage and treatment tactics for early cancer and precancerous conditions such as Barrett's esophagus. [3]

Modern endoscopy is more than just a "look." It's a platform for minimally invasive therapy: vascular clipping, thermocoagulation, variceal ligation, injection hemostasis, and removal of superficial tumors using mucosal resection and submucosal dissection. Proper technique selection can prevent surgery in a significant number of patients. [4]

Indications: When is the test really necessary?

Endoscopy is indicated for alarming symptoms (blood, anemia, dysphagia, unexplained weight loss), persistent dyspepsia and heartburn, suspected ulcers or complications, monitoring Barrett's esophagus, following treatment for early tumors, and acute bleeding from the upper esophagus. In bleeding situations, timely endoscopy changes the prognosis, allowing localization of the source and stopping blood loss. [5]

Cancer Risk and Precancerous Conditions:
Endoscopy is the primary method of screening and monitoring for Barrett's esophagus. Standardized "mapping" biopsy sampling according to the Seattle protocol is used, which increases the detection rate of dysplasia compared to selective sampling of material from only visually suspicious areas. [6]

Gastritis and Helicobacter pylori.
Endoscopy can perform a rapid urease test and topographic biopsies using the updated Sydney system, which provides almost complete sensitivity for detecting infection and allows for the staging of atrophy and intestinal metaplasia. This is important for assessing individual cancer risk. [7]

Functional and inflammatory diseases.
Eosinophilic esophagitis requires targeted multiple sampling of material from at least two levels of the esophagus, as changes may be focal. Endoscopy not only confirms the diagnosis but also helps assess activity using a standardized endoscopic score. [8]

Table 1. Indications for esophagogastroduodenoscopy and priority of implementation

Clinical situation	Examples of parts	Recommended priority
Signs of bleeding	melena, coffee grounds, hemodynamic instability	as soon as possible, within 24 hours; if varicose veins are suspected, no later than 12 hours
Dysphagia, odynophagia	feeling of being stuck, painful swallowing	fast direction
Anemia of unknown origin	iron deficiency without a source	as planned, but without delay
Dyspepsia with "red flags"	weight loss, vomiting blood, family history of cancer	priority
Barrett's esophagus monitoring	mapping biopsies according to the observation plan	planned at manual intervals

[9]

Contraindications and safety precautions

Absolute contraindications are few and associated with high immediate risk: perforation of a hollow organ without signs of stabilization, uncontrolled respiratory or cardiovascular failure, and refusal to consent. Relative contraindications include recent myocardial infarction, severe coagulopathy during planned procedures, and suspected cervical instability. The decision is made collectively, assessing the risks and benefits. [10]

Conditions with an increased risk of bleeding require correction before invasive procedures: adjust anticoagulant therapy, consider the type of intervention, and individual thrombotic risk. Joint UK-European guidelines apply here. [11]

During acute bleeding, relative contraindications shift: endoscopy becomes vital, and safe hemostasis and hemostasis become paramount. In the case of portal hypertension, specific measures are added—antibiotic prophylaxis and early endoscopy. [12]

Fasting and gastric emptying are important to reduce aspiration risks. In patients with delayed gastric emptying or massive bleeding, erythromycin prokinetic preparation is recommended before the procedure. [13]

Table 2. Contraindications and what to do with them

Category	Examples	Tactics
Absolute	perforation, unstable hemodynamics without stabilization	stabilize, discuss alternatives, then decide
Relative	active infarction, severe hypoxia	consultation, preparation, transfer if possible
Coagulopathy	targeting high-risk intervention	coagulation correction, anticoagulant plan
Full stomach	risk of aspiration	fasting, erythromycin if necessary

[14]

Preparation: fasting, medications, anticoagulants

The standard fasting regimen before a planned procedure is clear liquids are allowed for up to 2 hours, and light solid foods are allowed at least 6 hours before. This rule is supported by practical recommendations from anesthesiologists and is also applied in endoscopy. [15]

When taking anticoagulants and antiplatelet agents, the strategy depends on the planned procedure. For non-invasive diagnostic endoscopy, many medications can be continued. For high-risk interventions, the decision is made according to guidelines, taking into account the thrombotic risk and half-life of the specific agent. [16]

In cases of portal hypertension and suspected variceal bleeding, antibiotic prophylaxis and early endoscopy are prescribed in an emergency situation, as well as intravenous erythromycin to clear the stomach before examination. [17]

To improve visualization quality, antifoaming agents and mucolytics are recommended 15-30 minutes before the procedure. A combination of simethicone and N-acetylcysteine improves field clarity and enhances diagnostic value. [18]

Table 3. Preparation for the study

Direction	What to do	Comment
Starvation	liquids - up to 2 hours; food - at least 6 hours	reduces the risk of aspiration
Medicines	discuss anticoagulants and antiplatelet agents	individual cancellation or continuation plan
Prokinetic	erythromycin if retention of contents is suspected	facilitates stomach cleansing
Mucolytics and antifoams	simethicone with N-acetylcysteine	improves visibility of the mucous membrane

[19]

How the procedure works: high-quality stages

The procedure is performed orally or nasal (using an ultra-thin device), with the patient lying on the left side. The oropharynx is first anesthetized with a local spray, followed by sedation if necessary. The physician sequentially examines the oropharynx, the entire esophagus, the stomach, including a mandatory inspection of the fornix and antrum, and then the bulbus and descending portion of the duodenum, including the papillary zone. The examination is accompanied by photographic documentation of key areas. [20]

Quality directly depends on the inspection time and the completeness of the photographic report. Recording a standard set of images and minimizing the duration of the diagnostic examination are recommended to improve the detection of flat and early lesions. [21]

For improved visibility, irrigation and inflation with carbon dioxide are used, as it is absorbed more quickly and causes less discomfort. The use of mucolytics and antifoaming agents prior to the procedure improves assessment of the microrelief and vascular pattern. [22]

When suspicious areas are detected, targeted biopsies are performed and the location is noted in the protocol, which is critical for subsequent monitoring or treatment. [23]

Table 4. Minimum photographic documentation and organizational elements of quality

Element	What to include	For what
"Reference" zones	upper, middle, lower third of the esophagus; cardia; vault; body; antrum; bulb; descending part	traceability and completeness of inspection
Inspection time	at least 7 minutes when observing precancerous changes in the stomach	increased detection of early pathology
Visualization drugs	simethicone and N-acetylcysteine	reduction of bubbles and mucus
Gas for insufflation	carbon dioxide	less bloating and discomfort

[24]

Anesthesia and sedation: safety and monitoring

Options include local anesthesia of the throat alone, moderate sedation with benzodiazepines and an opioid, or sedation with propofol. The choice depends on the clinical situation, duration, and expected morbidity. Current guidelines emphasize the importance of standardized monitoring during and after sedation. [25]

Minimal monitoring includes pulse oximetry and blood pressure monitoring; with deeper sedation, capnography is indicated to reduce the likelihood of hypoxemia through early detection of hypoventilation. Personnel training in airway management is essential. [26]

Some patients may be offered transnasal ultrasonic endoscopy without sedation - this improves tolerability and reduces drug risks while maintaining diagnostic accuracy. [27]

After sedation, supervision and activity restrictions are required for the remainder of the day. The decision to discharge is made based on clinical criteria for recovery of consciousness and stability of vital signs. [28]

Table 5. Pain relief and monitoring options

Option	Where appropriate	Monitoring
Local anesthesia	short diagnostic procedures, transnasal technique	pulse oximetry, condition monitoring
Moderate sedation	most diagnostic and minor therapeutic procedures	pulse oximetry, pressure, readiness for oxygenation
Propofol	long and complex interventions	adding capnography, readiness for respiratory support

[29]

Biopsies and sampling protocols

The updated Sydney system recommends five biopsies to assess gastritis and risk: two from the antrum, one from the notch, and two from the body. The biopsies are collected separately, allowing for staging of atrophy and intestinal metaplasia and increasing the detection of Helicobacter pylori. [30]

Barrett's esophagus requires "mapping" biopsies using the Seattle protocol: 4-quadrant biopsies every 1-2 centimeters along the entire length of the altered mucosa, plus targeted biopsies of any suspicious areas. This approach increases the detection of dysplasia. [31]

Eosinophilic esophagitis requires at least six biopsies from different sections of the esophagus, as the lesion is focal. A standardized reference score is used to describe the endoscopic picture, which helps assess disease activity and treatment progress. [32]

Helicobacter pylori infection is confirmed by rapid urease test and histology, and, if possible, molecular methods are considered to select therapy taking into account resistance. Current consensus recommends treating all infected individuals. [33]

Table 6. Biopsy protocols

Clinical task	Scheme	Target
Gastritis and cancer risk	5 points on the Sydney system	staging of atrophy and metaplasia, H. pylori
Barrett's esophagus	4 quadrants every 1-2 cm plus targeting	detection of dysplasia
Eosinophilic esophagitis	≥6 samples from different levels	confirmation of diagnosis and activity
Confirmation of H. pylori	rapid urease test and histology	diagnostics and choice of therapy

[34]

Therapeutic options during the procedure

Bleeding is stopped by clipping, thermocoagulation, injection hemostasis, or powder hemostatic agents. If bleeding recurs, repeat endoscopy is recommended, and if unsuccessful, embolization or surgery is recommended. [35]

Esophageal varices are treated with rubber band ligation. In cases of portal hypertension, antibiotic prophylaxis and early endoscopy are mandatory; if the risk of recurrence is high, early shunting is considered. [36]

Benign strictures are dilated with bougies or balloons under visual control; in cases of refractoriness, additional methods of lumen fixation are used. Superficial neoplasms are removed by endoscopic mucosal resection or submucosal dissection. [37]

The use of modern hemostatic powders and cap-clips has expanded the range of controlled bleeding sources and reduced the need for emergency surgery. [38]

Table 7. Therapeutic manipulations and when to choose them

Task	Method	When is it preferable?
Bleeding from an ulcer	clip, thermocoagulation, injection	active bleeding, "vessel without bleeding"
Esophageal varices	ligation	primary hemostasis and secondary prevention
Diffuse leakage	hemostatic powder	difficult to identify sources
Early tumor	mucosal resection or dissection	superficial lesions without deep invasion

[39]

Acute bleeding: timing and steps that change the outcome

For upper gastrointestinal bleeding in hospitalized patients, endoscopy is recommended within 24 hours of admission, and if variceal bleeding is suspected, no later than 12 hours. Erythromycin infusion is helpful before the procedure to dislodge clots and improve visibility. [40]

After successful hemostasis, high-dose proton pump inhibitors are prescribed, which reduces the risk of recurrence. If recurrent bleeding occurs, repeat endoscopy with hemostasis is recommended; if hemostasis is unsuccessful, embolization or surgery is recommended. [41]

In patients with cirrhosis, short-term antibiotic prophylaxis and vasoactive therapy are mandatory, followed by programmatic ligation until varicose veins are eradicated and recurrence prevention. In certain high-risk groups, early portocaval shunt placement is considered. [42]

Table 8. Acute bleeding: brief algorithm

Stage	Action	Term
Resuscitation	stabilization, risk assessment	immediately
Preparation	intravenous erythromycin for large clot loads	before the procedure
Diagnosis and treatment	endoscopy with hemostasis	up to 24 hours, with varicose veins - up to 12 hours
Support	high-dose proton pump inhibitor secondary prevention plan	after the procedure

[43]

Alternatives to the classical method: when are they appropriate?

Transnasal ultrafine endoscopy is performed through the nose under local anesthesia without sedation. The examination is better tolerated by a significant proportion of patients, especially those at increased risk from sedatives, with comparable diagnostic accuracy. Nosebleeds are possible, but are usually short-lived. [44]

Magnetically guided capsule endoscopy of the stomach is developing as a noninvasive imaging method. Several studies have demonstrated accuracy similar to endoscopy in detecting significant changes, although standardization and specificity still vary. While some guidelines do not recommend the capsule for varicose vein screening, it may be considered an alternative in certain scenarios. [45]

Esophageal capsule screening for varices has been studied as a way to reduce invasiveness, but European guidelines emphasize the benefit of classical endoscopy for portal hypertension.[46]

Table 9. Comparison of alternatives

Technique	Pros	Cons	Where appropriate
Transnasal	better tolerability without sedation	narrower canal, risk of nosebleeds	diagnostics in patients at high risk of sedatives
Gastric capsule	non-invasiveness, comfort	variable specificity, limited therapy	preliminary examination when therapy is not planned
Esophageal capsule	screening comfort	inferior to standard endoscopy in portal hypertension	limited scenarios under research control

[47]

Risks and Complication Rates: The Honest Numbers

Diagnostic esophagogastroduodenoscopy is a low-risk procedure. The most common complications are transient hypoxemia under sedation, discomfort, and vomiting. Perforation and significant bleeding during a purely diagnostic examination are extremely rare. Large cohort analyses confirm that serious complications are exceptional. The risk increases with therapeutic interventions, severe comorbidities, and deep sedation. [48]

The use of capnography during deep sedation, oxygen as indicated, carbon dioxide for insufflation, and proper preparation reduces the risk of complications. Personnel should be proficient in airway management techniques and emergency care algorithms. [49]

Table 10. Complications and estimated frequencies

Complication	Probability in diagnosis	Risk factors
Perforation	extremely rare	strictures, therapeutic manipulations
Significant bleeding	extremely rare	biopsies for coagulopathies, therapy
Hypoxemia	more often with deep sedation	old age, lung diseases
Aspiration	low when fasting	full stomach, impaired protective reflexes

[50]

What should a good research protocol contain?

A good protocol is more than just general statements. It includes the clinical objective, a description of preparation, methods of anesthesia, a full description of all areas with reference zones and photographic documentation, the methods used to enhance visualization, a detailed biopsy procedure, a clear classification of detected changes, and recommendations for further management with reference to current guidelines. Such a protocol ensures continuity and reduces the risk of missed diagnoses. [51]

For risk pathologies—Barrett's esophagus, precancerous changes in the stomach—the protocol includes a biopsy "map" and follow-up timeframes based on recommendations from specialized societies. For gastritis, the topography is specified according to the Sydney system, and for eosinophilic esophagitis, the number of biopsies and the endoscopic score. [52]