Peptic Ulcer Disease and Gastrointestinal Bleeding

The named artery depends on the named wall

Naming the ulcer surface reveals the structure immediately beyond the wall.

A gastric ulcer on the lesser curvature can erode left-gastric branches and cause upper gastrointestinal hemorrhage.

A posterior duodenal-bulb ulcer may enter the gastroduodenal artery and bleed briskly.

An anterior duodenal ulcer more often opens into the peritoneal cavity because no large named artery lies against its free surface.

In the duodenal bulb, posterior means artery and anterior means free perforation.

Gastric versus duodenal ulcer

Site, cancer concern, and mucosal physiology outperform a rigid meal-timing rule.

Gastric ulcers often involve the lesser curvature or antrum after H pylori or NSAIDs weaken mucosal defense; endoscopic biopsy generally excludes malignancy.

Duodenal ulcers commonly occupy the bulb and track with H pylori, excess acid delivery, or impaired bicarbonate defense; primary duodenal malignancy is far less likely.

Gastric-ulcer pain may worsen with food, while duodenal-ulcer pain may briefly improve before recurring hours later or at night, but the overlap makes timing insufficient by itself.

Primary diagnostic image

Meal timing can support an ulcer location, but it cannot establish one.

Blood changes appearance with time and volume

Time darkens blood; rapid transit preserves red color.

Slow or moderate upper gastrointestinal bleeding becomes black, tarry melena after exposure to acid, enzymes, and intestinal transit.

Very rapid upper bleeding can emerge as red hematochezia, whereas small chronic losses from any level may appear only as iron-deficiency anemia or positive stool testing.

Hematochezia with shock can still come from a brisk upper gastrointestinal hemorrhage.

The ligament of Treitz divides upper from lower bleeding

Blood appearance locates a source only after transit speed is considered.

Bleeding proximal to the ligament of Treitz arises from the esophagus, stomach, or duodenum and commonly causes hematemesis, coffee-ground emesis, or melena.

Bleeding distal to the ligament often comes from colon or anorectum and commonly causes hematochezia, while the small bowel occupies the intervening territory.

A brisk upper source can move fast enough to cause hematochezia, while slow right-colonic or small-bowel loss can produce dark stool and iron-deficiency anemia.

H pylori and NSAIDs reach the same ulcer by different routes

H pylori alters inflammation and acid control; NSAIDs remove prostaglandin-supported defense.

H pylori causes chronic gastritis, disrupts somatostatin-gastrin signaling, weakens bicarbonate defense, and can increase duodenal acid exposure or produce atrophic gastric injury according to its distribution.

By inhibiting cyclooxygenase-dependent prostaglandin synthesis, NSAIDs reduce mucosal blood flow, mucus, bicarbonate, epithelial repair, and platelet function.

Once acid and pepsin overwhelm epithelial defense, a break crossing the muscularis mucosae becomes an ulcer that can bleed, penetrate, perforate, or scar.

Hemorrhage, obstruction, perforation, and penetration

Presentation changes when an ulcer reaches a vessel, narrows the outlet, or leaves the wall.

Hemorrhage, the most common major ulcer complication, ranges from occult iron loss to shock with hematemesis, melena, or hematochezia.

Edema, spasm, or scarring near the pylorus or proximal duodenum can obstruct the gastric outlet, causing early satiety, retained food, succussion splash, and nonbilious vomiting.

Perforation spills gas and contents into the peritoneum, whereas penetration enters an adjacent organ such as the pancreas without necessarily producing free intraperitoneal air.