Gastrointestinal Endoscopy¶
Chapter 333 | Part 10: Disorders of the Gastrointestinal System
KEY CLINICAL POINTS¶
- Endoscopy is a critical diagnostic and therapeutic tool for gastrointestinal disorders, enabling visualization, biopsy, and intervention for conditions like ulcers, varices, tumors, and obstructions.
- Key procedures include upper endoscopy (EGD), colonoscopy, and small-bowel endoscopy, with specialized techniques like EMR, ESD, and stent placement for resection and palliation.
- Antibiotic prophylaxis is recommended for certain endoscopic procedures (e.g., ERCP, EUS-FNA) to prevent infections, while antithrombotic management must balance bleeding risk and thrombosis prevention.
1. DEFINITION & OVERVIEW¶
Gastrointestinal endoscopy involves the use of flexible endoscopes to visualize and treat the upper and lower gastrointestinal tract. It serves diagnostic, therapeutic, and surveillance roles for conditions such as peptic ulcers, varices, tumors, and inflammatory bowel disease.
1.1 Historical Context¶
Modern endoscopy began with the introduction of semirigid and flexible gastroscopes in the mid-20th century, enabling advancements in diagnosis and treatment of digestive diseases.
1.2 Endoscope Function¶
Endoscopes provide real-time imaging, allow for biopsy collection, and facilitate therapeutic interventions (e.g., hemostasis, polypectomy). High-resolution and narrow-band imaging enhance lesion detection.
2. EPIDEMIOLOGY¶
Endoscopy is widely used for conditions like peptic ulcer disease (PUD), gastrointestinal bleeding, and colorectal cancer. Colorectal cancer incidence is rising, with screening strategies targeting high-risk populations.
3. ETIOLOGY & PATHOPHYSIOLOGY¶
Conditions like peptic ulcers (H. pylori, NSAIDs), varices (portal hypertension), and tumors (adenocarcinoma) are managed via endoscopic techniques. Pathophysiology includes mucosal damage, vascular abnormalities, and neoplastic growth.
3.1 Peptic Ulcers¶
Caused by H. pylori infection, NSAID use, or acid hypersecretion. Ulcers may present with bleeding, perforation, or obstruction.
3.2 Varices¶
Portal hypertension leads to esophageal or gastric varices, which may rupture and cause life-threatening hemorrhage.
4. CLINICAL FEATURES¶
Symptoms vary by condition: dyspepsia, hematemesis, melena, abdominal pain, or obstruction. Signs include visible vessels, adherent clots, or stigmata of bleeding.
4.1 Bleeding Stigmata¶
Clean base (low rebleeding risk), flat pigmented spots (moderate risk), or visible vessel/active spurting (high risk).
4.2 Obstruction¶
May present with vomiting, abdominal distension, or inability to pass stool. Pseudoobstruction is often due to electrolyte imbalances or medications.
5. DIFFERENTIAL DIAGNOSIS¶
Conditions mimicking endoscopic findings include vascular ectasias, Dieulafoy’s lesions, and tumors. Distinguishing between benign and malignant lesions is critical for management.
6. INVESTIGATIONS & DIAGNOSIS¶
Diagnostic tools include endoscopy, imaging (CT, MRI, MRCP), and lab tests (CBC, liver function). Endoscopy is the gold standard for visualizing mucosal lesions and obtaining biopsies.
6.1 Imaging Modalities¶
MRCP and EUS are essential for bile duct stones and pancreatic pathology. CT colonography is used for colorectal cancer screening.
6.2 Endoscopic Techniques¶
Capsule endoscopy and deep enteroscopy are used for small-bowel evaluation. EUS guides staging and therapeutic interventions.
7. MANAGEMENT & TREATMENT¶
Therapeutic endoscopy includes hemostasis (clips, cyanoacrylate), resection (EMR, ESD), and stent placement. Pharmacologic management involves PPIs, antibiotics, and anticoagulant adjustment.
Table 333-1: Antibiotic Prophylaxis for Endoscopic Procedures¶
| Patient Condition | Procedure Contemplated | Goal of Prophylaxis | Periprocedural Antibiotic Prophylaxis |
|---|---|---|---|
| All cardiac conditions | Any endoscopic procedure | Prevention of infective endocarditis | Not recommended |
| Patient Condition | Procedure Contemplated | Goal of Prophylaxis | Periprocedural Antibiotic Prophylaxis |
|---|---|---|---|
| Bile duct obstruction in the absence of cholangitis | ERCP with complete drainage | Prevention of cholangitis | Not recommended |
| Bile duct obstruction in the absence of cholangitis | ERCP with anticipated incomplete drainage | Prevention of cholangitis | Recommended; continue antibiotics after the procedure |
| Sterile pancreatic fluid collection | Transmural drainage | Prevention of cyst infection | Recommended |
| Solid lesion along upper GI tract | EUS-FNA or FNB | Prevention of local infection | Not recommended |
| All patients | Percutaneous endoscopic feeding tube placement | Prevention of peristomal infection | Recommended |
Table 333-3: Colorectal Cancer Screening Strategies¶
| Patient Group | Screening Recommendations | Comments |
|---|---|---|
| Average-risk individuals (45–75 years) | Colonoscopy every 10 years | Gold standard for cancer prevention |
| Average-risk individuals (45–75 years) | Multitargeted stool DNA test every 1–3 years | Less sensitive than colonoscopy |
| Average-risk individuals (45–75 years) | FIT or HSgFOBT annually | Less sensitive than colonoscopy |
| Average-risk individuals (>75 years) | Selective screening | Based on patient health and preferences |
| Personal history of polyps or CRC | Repeat colonoscopy in 3–10 years | Based on adenoma size and histology |
| Inflammatory bowel disease | Colonoscopy with biopsies every 1–2 years | For detection of dysplasia |
7.1 Hemostasis¶
Endoscopic therapies for bleeding include injection of epinephrine, thermal coagulation, and clip application. Cyanoacrylate is used for gastric varices.
8. PROGNOSIS & COMPLICATIONS¶
Complications include bleeding, perforation, and infection. Prognosis varies by condition: early-stage cancers have better outcomes with endoscopic resection, while advanced malignancies may require palliative measures.
8.1 Bleeding Complications¶
Rebleeding risk varies by ulcer type (clean base: 3–5%, visible vessel: 40%). Endoscopic therapy reduces rebleeding rates.
8.2 Post-ERCP Complications¶
Pancreatitis occurs in ~5% of ERCP cases, with higher risk in patients with normal bile ducts.
9. SPECIAL CONSIDERATIONS¶
Pregnancy, pediatric, and elderly patients require tailored approaches. For example, endoscopy is used for prenatal diagnosis of fetal abnormalities, and elderly patients may need slower sedation protocols.
9.1 Pregnancy¶
Endoscopy is generally safe in pregnancy, with caution for sedation and radiation exposure during imaging.
9.2 Pediatric Patients¶
Flexible endoscopes and sedation protocols are adapted for children, with emphasis on minimizing complications.
10. KEY POINTS & CLINICAL PEARLS¶
Endoscopy is essential for diagnosing and managing gastrointestinal disorders. Antibiotic prophylaxis is indicated for certain procedures, and anticoagulant management must balance bleeding risk. Early detection of Barrett’s esophagus and colorectal polyps improves outcomes.