What is Peptic Ulcer Disease?
Peptic ulcer disease refers to the presence of one or more sores in the stomach or duodenum. The term "peptic" refers to the stomach, while an ulcer is a sore or break in a membrane. Gastric ulcers, which occur in the stomach, and duodenal ulcers, which occur in the duodenum, are the most common types of peptic ulcers.
Anatomy of the Gastrointestinal Tract
The inner wall of the gastrointestinal tract is lined with mucosa, which consists of three cell layers. The epithelial layer is the innermost layer and is responsible for absorbing and secreting mucus and digestive enzymes. The middle layer, called the lamina propria, contains blood and lymph vessels. The outermost layer, known as the muscularis mucosa, is composed of smooth muscle that aids in the breakdown of food.
The Stomach
The stomach is divided into four regions: the cardia, the fundus, the body, and the pyloric antrum. It also has a pyloric sphincter, or valve, at the end to keep food inside for digestion. Different parts of the stomach contain different proportions of gastric glands. The cardia has mostly foveolar cells that secrete mucus. The fundus and body have mostly parietal cells that secrete hydrochloric acid and chief cells that secrete pepsinogen, an enzyme that digests protein. The antrum has mostly G cells that secrete gastrin in response to food entering the stomach.
Brunner Glands and Prostaglandins
The duodenum, which is part of the small intestine, contains Brunner glands that secrete mucus rich in bicarbonate ions. The stomach and duodenal mucosa are protected from the digestive enzymes and hydrochloric acid by mucus and bicarbonate ions secreted by the duodenum. Prostaglandins, small signaling molecules, are also secreted in the stomach and duodenum. They stimulate mucus and bicarbonate secretion, vasodilation of blood vessels, and new epithelial cell growth. Prostaglandins also inhibit acid secretion.
Causes of Peptic Ulcer Disease
The main cause of gastric and duodenal ulcers is an infection with H. pylori bacteria. These bacteria colonize the gastric mucosa and cause damage to mucosal cells. Nonsteroidal anti-inflammatory drugs (NSAIDs), like ibuprofen, can also cause gastric ulcers by reducing the level of protective prostaglandins. Zollinger Ellison syndrome, caused by a gastrinoma tumor, is a rare cause of peptic ulcer disease.
Symptoms and Complications
The main symptom of peptic ulcers is epigastric pain, which is an aching or burning sensation in the upper abdomen. Other symptoms include bloating, belching, and vomiting. Gastric ulcers are associated with weight loss, while duodenal ulcers are associated with weight gain. Complications of peptic ulcers include bleeding, perforation, and gastric outlet obstruction.
Bleeding and Perforation
Ulcers can erode into blood vessels, causing bleeding. Gastric ulcers on the lesser curvature of the stomach can erode into the left gastric artery, while duodenal ulcers on the posterior wall of the duodenum can erode into the gastroduodenal artery. Perforation occurs when an ulcer erodes all the way through the wall of the stomach or duodenum, allowing gastrointestinal contents to enter the peritoneal space. Perforation can lead to referred pain in the shoulder.
Gastric Outlet Obstruction
In rare cases, duodenal ulcers near the pyloric sphincter can cause edema or scarring that obstructs the normal passage of gastric contents into the intestines. This can result in gastric outlet obstruction, leading to nausea and vomiting.
Diagnosis and Treatment
Peptic ulcers can be diagnosed with upper endoscopy, which involves inserting a tube into the esophagus, stomach, and proximal duodenum to visualize the ulcer. A biopsy may also be taken to check for malignant cells and H. pylori infection. Treatment of peptic ulcers depends on the underlying cause. H. pylori infection is usually treated with antibiotics and acid-lowering medications. It is important to avoid substances that worsen peptic ulcers, such as NSAIDs, alcohol, tobacco, and caffeine. In severe cases, surgery may be necessary.
