An ulcer is a pitting of the mucous or skin tissue surface due to erosion of that tissue. They commonly occur in the gastrointestinal tract or on the skin. Upper gastrointestinal tract ulcers, called peptic ulcers, are common, occuring in 1 to 10 percent of the population in developed countries.
In the United States and Europe peptic ulcers usually occur in the duodenum near the junction with the stomach, but may be found in the stomach wall. The single, round or oval lesions may be shallow erosions that heal rapidly or may become deep and chronic, eroding again several months after healing. They may perforate the entire wall, leading to significant bleeding and possibly death. Pain, the predominant symptom, occurs one to three hours after a meal and frequently during nighttime.
Evidence suggests a variety of causes for ulcer diseases. Ulcers within the main body of the stomach (corpus ulcers) are associated with different meal-stimulated acid responses and different healing rates than ulcers near the pyloric sphincter (prepyloric ulcers). Reflux of bile from the duodenum into the stomach may cause prepyloric ulcers. Duodenal ulcers are frequently associated with excess acid secretion. Entry of acid-peptic contents into the lower esophagus can also cause ulcers there.
Stress ulcers develop acutely in the stomach and may be associated with less pain but significant bleeding. They are frequently multiple lesions and usually occur in patients with severe physical injury, trauma, burns, or who have had major surgery, especially of the central nervous system. Stress ulcers are more common in elderly or debilitated patients.
Multiple factors lead to the development of a peptic ulcer. Ulcers develop when there is imbalance between acid-peptic secretions and mucous and bicarbonate (buffer) secretions, or other protective factors. Chemicals such as prostaglandins and somatostatin, which are produced by cells in the stomach and duodenum, help prevent ulcers by increasing mucous or bicarbonate secretion, increasing blood flow, or inhibiting gastrin (stimulant hormone) or acid secretion. Aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) used to treat arthritis may contribute to ulcer disease by acting on these mechanisms. Psychological stress, while not a direct cause of ulcers in humans, may neurologically alter gastroduodenal blood flow and acid secretion. Infection with the bacterium Helicobacter pylori has been implicated as a causative factor in most gastric ulcers, in gastric inflammation, and duodenal ulcers. Certain strains of H. pylori are associated with ulcers, and suggest possible development of an antiulcer vaccine.
The role of diet in causing peptic ulcers and the use of dietary regimens to promote ulcer healing remains controversial. Indian researchers believe that spicy foods may contribute to ulcer disease and diets high in unrefined wheat, rice, spinach, cabbage, and whole milk may protect against duodenal ulcer. It is currently believed in North America that spicy foods or high intake of alcohol or coffee do not cause ulcer disease, but stimulants of gastric acid secretion such as alcohol or caffeine should be restricted in ulcer patients. In spite of their common use, little evidence suggests that bland hospital diets improve ulcer symptoms or promote healing. However, diets including foods such as milk, cream, cheese, and eggs, fiber-rich diets, and frequent small meals that provide more constant buffering of gastric contents, are thought to be beneficial.
Ulcers are usually treated with drugs that inhibit hydrochloric acid secretion or buffer secreted acid. These include agents such as cimetidine and ranitidine, which block the receptors in the stomach that regulate gastric secretion; omeprazole, which inhibits enzymes required for synthesis of gastric acid; or buffering drugs, which neutralize acid. Other drugs acting on acid secretion, on the inner gastric surface, or elsewhere, include colloidal bismuth, sucralfate, and pirenzepine. Treatment with antibiotics kills H. pylori bacteria. When drug therapy alone fails, surgery can remove the distal stomach, which produces the gastric stimulant gastrin. Surgical severing of distal parts of the vagal nerves to the stomach can remove central nervous system stimulation. Surgery can sometimes be averted by using endoscopes to bring laser heat or electric currents to the ulcer site to stop the bleeding.
Decubitus ulcers, or bedsores, are due to pressure from prolonged bed rest. Other skin ulcers may result from bacterial infections, such as syphilis, tuberculosis, or anthrax, or impaired circulation of skin. They can be treated topically with antibiotics, zinc oxide, and other agents.