gastric ulcer

Pathophysiology: Gastric ulcers result from an imbalance between mucosal protective factors (mucus-bicarbonate layer, prostaglandins, blood flow) and damaging factors (acid, pepsin, H. pylori, NSAIDs). H. pylori causes chronic gastritis predominantly in the antrum, impairing mucosal defenses; it accounts for a large majority of gastric ulcers. NSAIDs inhibit COX-1, reducing protective prostaglandin synthesis, decreasing mucus/bicarbonate secretion and mucosal blood flow. Other risk factors include smoking, alcohol, stress (Curling ulcer in burns, Cushing ulcer in CNS injury), and Zollinger-Ellison syndrome (gastrinoma causing acid hypersecretion, though more classically duodenal/multiple ulcers).

Clinical features: Epigastric pain that classically worsens with meals (food stimulates acid secretion, exacerbating mucosal damage), weight loss (due to pain-associated food avoidance), nausea. Can present with complications: hemorrhage (hematemesis, melena), perforation (acute abdomen, free air under diaphragm), gastric outlet obstruction, and rarely penetration into adjacent organs (e.g., pancreas causing referred back pain).

Location: Most commonly found on the lesser curvature of the antrum/body junction. Ulcers on the greater curvature or elsewhere raise higher suspicion for malignancy.

Malignancy risk: Unlike duodenal ulcers (almost always benign), gastric ulcers require biopsy of the ulcer margins to rule out gastric adenocarcinoma. Malignant ulcers often have irregular, heaped-up margins, while benign ulcers have smooth, punched-out edges with radiating folds.

Diagnosis: Upper endoscopy (EGD) is gold standard, allowing direct visualization and biopsy. Testing for H. pylori via urea breath test, stool antigen, or biopsy-based tests (rapid urease test, histology).

Treatment: Eradicate H. pylori if present (triple/quadruple therapy: PPI + clarithromycin + amoxicillin/metronidazole, or bismuth-based quadruple therapy). Discontinue NSAIDs if possible. PPIs are first-line for acid suppression and healing. Repeat endoscopy typically performed in gastric ulcers to confirm healing and rule out malignancy, unlike duodenal ulcers.

High-yield boards points: Gastric ulcer pain worsens with food (weight loss) vs. duodenal ulcer pain improves with food (weight gain). Gastric ulcers require biopsy to exclude malignancy; duodenal ulcers rarely require biopsy. H. pylori is present in ~70% of gastric ulcers and ~90% of duodenal ulcers.