A 52-year-old man with a 10-year history of rheumatoid arthritis has been on naproxen 500 mg twice daily for 3 years. He now presents with epigastric pain, nausea, and melena. Which investigation is most appropriate to confirm the diagnosis of NSAID-induced gastropathy?

Explanation

## Investigation of Choice for NSAID-Induced Gastropathy ### Why Upper GI Endoscopy Is the Gold Standard **Key Point:** Upper gastrointestinal endoscopy is the investigation of choice for suspected NSAID-induced gastropathy because it directly visualizes the gastric and duodenal mucosa, allowing: - Direct visualization of erosions, ulcers, or hemorrhagic lesions - Identification of the exact location and severity of mucosal damage - Tissue biopsy if malignancy is suspected - Therapeutic intervention (hemostasis) if active bleeding is present ### Clinical Presentation Context **Clinical Pearl:** This patient has classic features of NSAID-induced gastropathy: - Prolonged NSAID use (3 years) - Acute presentation with melena (indicating GI bleeding) - Epigastric pain and nausea These symptoms demand direct visualization to rule out other causes (peptic ulcer disease, gastric malignancy, Mallory-Weiss tear) and assess bleeding severity. ### Why Endoscopy Trumps Other Tests | Investigation | Sensitivity | Specificity | Limitation | |---|---|---|---| | Upper GI endoscopy | >95% | Gold standard | Invasive, requires sedation | | Fecal occult blood test | Moderate | Low | Non-specific; cannot localize source | | Abdominal ultrasound | Low | Low | Poor visualization of gastric mucosa | | Serum gastrin | N/A | N/A | Irrelevant; rules out Zollinger-Ellison syndrome, not NSAID injury | **High-Yield:** Endoscopy is both diagnostic AND therapeutic — it can identify the bleeding source and perform hemostasis (injection, cautery, clips) in the same procedure. ### Mechanism of NSAID Gastropathy **Key Point:** NSAIDs inhibit COX-1 and COX-2, reducing prostaglandin E₂ and prostacyclin production. This leads to: - Decreased gastric mucus secretion - Reduced bicarbonate secretion - Diminished mucosal blood flow - Impaired mucosal healing These changes predispose to erosion and ulceration, especially in the antrum and lesser curve of the stomach.