Upper GI Endoscopy — Procedure Guide, Recovery & Risks | MyMedicPlus

Upper gastrointestinal endoscopy — also called gastroscopy or oesophagogastroduodenoscopy (OGD) — is a diagnostic and therapeutic endoscopic procedure in which a thin, flexible, high-definition video endoscope is passed through the mouth, pharynx, oesophagus, stomach, and first and second parts of the duodenum to enable direct visualisation of the upper gastrointestinal tract mucosa. The modern video endoscope (gastroscope) contains a charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS) camera at its distal tip that transmits a high-definition colour image to a display monitor, supplemented by a light source delivered through glass fibres or LED illumination. Advanced imaging modalities integrated into modern gastroscopes include narrow band imaging (NBI — which enhances mucosal surface vascular patterns for early dysplasia and Barrett's oesophagus detection), chromoendoscopy using topically applied stains (indigo carmine, crystal violet), and endocytoscopy providing cellular-level magnification. The gastroscope contains multiple working channels through which diagnostic tools — biopsy forceps, cytology brushes — and therapeutic devices — injection needles, haemostatic clips, endoscopic band ligators, argon plasma coagulators, stents, and polypectomy snares — can be passed. Gastroscopy is one of the most commonly performed endoscopic procedures worldwide, providing definitive diagnosis and increasingly definitive treatment of many upper GI conditions that previously required open surgery.

Upper GI endoscopy is indicated for a broad range of upper digestive tract symptoms and conditions. Diagnostic indications include persistent heartburn or gastro-oesophageal reflux disease (GORD) unresponsive to proton pump inhibitors, dysphagia (difficulty swallowing food or liquids), odynophagia (painful swallowing), unexplained upper abdominal pain or epigastric discomfort, nausea and vomiting persisting over 4 weeks, unexplained weight loss with upper GI symptoms, iron deficiency anaemia or low haemoglobin of unknown cause, upper gastrointestinal bleeding presenting as haematemesis (vomiting blood) or melaena (black tarry stools), suspected peptic ulcer disease or H. pylori infection, Barrett's oesophagus surveillance, and investigation of abnormal findings on barium swallow examination, CT scan, or cross-sectional imaging. Therapeutic gastroscopy is performed for haemostatic treatment of bleeding ulcers, variceal band ligation, oesophageal dilation for strictures, polyp removal, foreign body retrieval, and percutaneous endoscopic gastrostomy (PEG) tube insertion. Urgent gastroscopy within 24 hours is recommended for acute upper GI bleeding.

The patient fasts for at least 6 hours (solids) and 2–4 hours (clear fluids) before the procedure to ensure an empty stomach for optimal visualisation and to reduce aspiration risk. In the endoscopy unit, the patient lies in the left lateral position on a procedure trolley with a protective mouth guard placed between the teeth to protect the scope and patient's dentition. Throat anaesthetic spray (lidocaine) is applied to the pharynx to suppress the gag reflex, and intravenous sedation with midazolam (with or without an opioid analgesic such as fentanyl) is administered through a cannula to provide conscious sedation and amnesia; some patients opt for unsedated endoscopy with throat spray alone. The endoscope is introduced over the tongue with the patient's cooperation in swallowing, and advanced under direct vision through the cricopharyngeus muscle into the oesophagus, then gently manoeuvred through the oesophagus into the stomach with careful air or CO2 insufflation to distend the lumen for visualisation. The gastric antrum, incisura, body, fundus, and cardia are inspected on the way to and from the duodenum. Biopsies are taken with flexible forceps through the instrument channel. Therapeutic procedures are performed as required — haemostatic clips, adrenaline injection, variceal banding, polypectomy, or dilation. Total procedure time is 15–30 minutes for diagnostic scope, longer for therapeutic interventions.

Upper GI endoscopy provides a definitive diagnosis of upper gastrointestinal pathology in 85–90% of cases when significant disease is present. H. pylori infection is accurately detected by rapid urease testing of antral biopsies with 95% sensitivity and specificity. Early gastric cancer, early oesophageal adenocarcinoma, and high-grade dysplasia in Barrett's oesophagus are detectable and treatable endoscopically before surgical intervention becomes necessary. Therapeutic endoscopy achieves haemostasis in acute peptic ulcer bleeding in over 90% of cases, avoiding emergency surgery. Endoscopic variceal band ligation controls active oesophageal variceal bleeding in 90–95% of cases. Oesophageal dilation relieves dysphagia from strictures in over 85% of patients. As both a diagnostic and therapeutic tool without external incision, upper GI endoscopy delivers high-value clinical information that directly guides medical or surgical management decisions while simultaneously treating many conditions in the same session.

Upper GI endoscopy is a very safe procedure with a serious complication rate below 1 in 1,000 for diagnostic gastroscopy. Perforation of the oesophagus, stomach, or duodenum is the most serious risk, occurring in fewer than 0.1% of diagnostic scopes but rising to 0.5–1% with therapeutic procedures such as dilation. Post-procedure bleeding occurs in 0.1–0.5% following biopsy or therapeutic procedures such as polypectomy or variceal treatment. Aspiration pneumonia is a risk in sedated patients with impaired airway reflexes or in those who have not fasted adequately. Adverse reactions to intravenous sedation including respiratory depression are rare with careful monitoring and dose titration. Temporary sore throat from pharyngeal passage of the scope and mild abdominal discomfort or bloating from air or CO2 insufflation resolve within a few hours. Bacteraemia can occur but is rarely clinically significant in immunocompetent patients. All risks are substantially higher with therapeutic compared with purely diagnostic endoscopy, and patients with comorbidities require careful pre-procedure assessment.

After the procedure, patients rest in a recovery area for 30–60 minutes until sedation wears off sufficiently — longer if higher sedation doses were required. A mild sore throat and mild bloating from air insufflation are normal and resolve within a few hours; warm liquids and soft food on the day of the procedure ease throat discomfort. Patients who received intravenous sedation must not drive, operate machinery, sign legal documents, or be left unaccompanied for 24 hours following discharge, and must arrange a responsible adult to accompany them home — verbal and written instructions are provided. Patients who had only throat spray (unsedated endoscopy) may drive and return to normal activities once the anaesthetic effect wears off, typically within 30–45 minutes. Eating and drinking may resume 30–60 minutes after the procedure. Biopsy results are typically available within 5–7 working days and are communicated to the patient by the referring clinician. H. pylori eradication therapy is initiated if the CLO test is positive. Follow-up endoscopy is arranged according to the findings — at 6 weeks for ulcers, 3 years for low-grade Barrett's oesophagus, or sooner for suspicious lesions.