Endoscopy

Diagnostic procedures by conventional endoscopy include cell and tissue sample collection by brush or biopsy forceps. Several different types of endoscopes provide additional diagnostic and therapeutic functions. Ultrasound-equipped endoscopes can evaluate blood flow or provide imaging of mucosal, submucosal, or extraluminal lesions. Endoscopic ultrasound can provide information (eg, the depth and extent of lesions) that is not available via conventional endoscopy. Also, fine-needle aspiration of both intraluminal and extraluminal lesions can be done with endoscopic ultrasound guidance.

Conventional endoscopes cannot visualize the vast majority of the small intestine. Push enteroscopy uses a longer endoscope that can be manually advanced into the distal duodenum or proximal jejunum.

Therapeutic endoscopic procedures include

• Removal of foreign bodies

• Hemostasis by hemoclips placement, injection of medications, hemostatic sprays, thermal coagulation, laser photocoagulation, variceal banding, or sclerotherapy

• Debulking of tumors by laser or bipolar electrocoagulation

• Ablative therapy of premalignant lesions

• Removal of polyps

• Mucosal and/or submucosal tissue resection

• Dilation of webs or strictures

• Stent placement

• Reduction of volvulus or intussusception

• Decompression of acute or subacute colonic dilation

• Feeding tube placement

• Drainage of pancreatic cysts

• Endoscopic bariatric procedures (eg, placement of intragastric balloons, endoscopic sleeve gastrectomy)

• Endoscopic myotomy (eg, for esophageal achalasia, refractory gastroparesis)

• Transoral incisionless fundoplication

Absolute contraindications to endoscopy include

• Shock

• Acute myocardial infarction

• Peritonitis

• Acute perforation

• Fulminant colitis

Relative contraindications include poor patient cooperation, coma (unless the patient is intubated), and cardiac arrhythmias or recent myocardial ischemia.

Patients taking anticoagulants or chronic nonsteroidal anti-inflammatory drug therapy can safely undergo diagnostic endoscopy. However, if there is a possibility that biopsy or thermal therapy will be done, anticoagulants should be stopped for an appropriate interval before the procedure (1). Oral iron-containing medications should be stopped 4 to 5 days before colonoscopy because certain green vegetables interact with iron to form a sticky residue that is difficult to remove with a bowel preparation and interferes with visualization.

The American Heart Association and American College of Cardiology (ACC/AHA) no longer recommend endocarditis prophylaxis for patients having routine gastrointestinal endoscopy (2 ). The American Society for Gastrointestinal Endoscopy also recommends against antibiotic prophylaxis before any gastrointestinal procedures in patients with synthetic vascular grafts or other nonvalvular cardiovascular devices (eg, implantable electronic devices) or for patients with an orthopedic prosthesis (3). However, antibiotics are used before placement of a percutaneous endoscopic gastrostomy (PEG) tube to prevent site infection and often before endoscopic retrograde cholangiopancreatography (ERCP) or other procedures accessing the hepatobiliary system.

For patients on peritoneal dialysis, drainage of the abdomen prior to colonoscopy is recommended to prevent peritonitis (4). The benefit of pre-colonoscopy antibiotics in peritoneal dialysis patients to prevent peritonitis is unknown (4, 5).

Routine preparations for endoscopy include no solids for 8 hours and no liquids for 2 to 4 hours before the procedure (see the American Society of Anesthesiologists Task Force's 2017 guidelines [1] and 2023 guidelines [2]). Additionally, colonoscopy requires cleansing of the colon. A variety of regimens may be used, but all typically include a full or clear liquid diet for 24 to 48 hours and some type of laxative, with or without an enema (3). Bowel-cleansing preparations using a high volume of an electrolyte-containing liquid are commonly used. The preparations are available in different volumes (typically ranging between 2 L and 4 L) and have varying degrees of efficacy. Giving preparations in a split-dose fashion, ie, giving half the volume the day before the procedure and half the volume the day of the procedure, has been shown to improve patient compliance, examination quality, and adenoma detection rate (4).

Patients who cannot tolerate bowel-cleansing preparations may be given magnesium citrate, sodium phosphate, polyethylene glycol, lactulose, or other laxatives. Enemas can be done with either sodium phosphate or tap water. Phosphate preparations should not be used in patients with renal insufficiency.

GLP-1 agonists, such as liraglutide and semaglutide, have emerged as significant therapeutic agents for the management ofobesity and type 2 diabetes. However, their administration prior to endoscopic procedures necessitates careful consideration due to the potential impact on gastrointestinal motility. These agents can induce alterations in gastric emptying, raising concerns about the risk of delayed gastric emptying and its implications for sedation and anesthesia during procedures. Therefore, it is prudent for health care providers to evaluate the timing of GLP-1 administration relative to scheduled endoscopic interventions. Guidelines support cessation of weekly dosed GLP-1 medications the week prior to endoscopy (5).  Additionally, individualized assessment of patient-specific factors, including the nature of the procedure and overall health status, is essential to ensure optimal safety and efficacy as there is not yet consensus on the optimal duration these medications need to be held to minimize the risk of aspiration (6, 7).  In centers or clinical scenarios where it is available, abdominal ultrasound to assess presence of gastric contents can mitigate risk of aspiration and help guide discussions on the risks and benefits of the procedure (5). Adhering to these principles can help mitigate complications and enhance procedural outcomes in this patient population.

In video capsule endoscopy (wireless video endoscopy), patients swallow a disposable capsule containing a camera that transmits images to an external recorder; the capsule does not need to be retrieved. This noninvasive technology provides diagnostic imaging of the small bowel that is otherwise difficult to obtain by conventional endoscopies.

This procedure is particularly useful in patients with occult gastrointestinal bleeding and for detection of mucosal abnormalities.

Capsule endoscopy is more difficult in the colon and, while feasible, is not commonly used as a modality for colorectal cancer screening (1).

The following English-language resources may be useful. Please note that The Manual is not responsible for the content of these resources.

1. American Heart Association and American College of Cardiology: 2020 ACC/AHA Guideline for the Management of Patients With Valvular Heart Disease: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines (2020)

2. American Society of Anesthesiologists Task Force: 2017 Practice Guidelines for Preoperative Fasting and the Use of Pharmacologic Agents to Reduce the Risk of Pulmonary Aspiration: Application to Healthy Patients Undergoing Elective Procedures: An Updated Report by the American Society of Anesthesiologists Task Force on Preoperative Fasting and the Use of Pharmacologic Agents to Reduce the Risk of Pulmonary Aspiration (2017)

3. American Society of Anesthesiologists Task Force: 2023 Practice Guidelines for Preoperative Fasting: Carbohydrate-containing Clear Liquids with or without Protein, Chewing Gum, and Pediatric Fasting Duration—A Modular Update of the 2017 American Society of Anesthesiologists Practice Guidelines for Preoperative Fasting (2023)