Peptic ulcer disease encompasses both gastric ulcers (GU) and duodenal ulcers (DU). An ulcer in either region is defined as a lesion with a length of more than 5 mm and a depth reaching the submucosa.
Burden
Peptic ulcer disease is common in the United States, with an overall lifetime occurrence of 8.4% of the population and a yearly incidence of about 4 million cases. It significantly affects quality of life, and its burden also has a large cost: about 3 billion dollars of hospitalisation, 2 billion dollars of physician visits, and 1 billion dollars lost to reduced productivity and absence from work.
Risk factors
The odds ratios of different conditions that can lead to peptic ulcer disease in the United States are:
- H. pylori infection → 3.7;
- NSAIDs → 3.3;
- COPD → 2.34;
- chronic renal insufficiency → 2.29;
- current tobacco use → 1.99;
- former tobacco use → 1.55;
- older age → 1.67;
- three or more doctor visits in a year → 1.49;
- coronary heart disease → 1.46;
- former alcohol use → 1.29;
- African American race → 1.20;
- obesity → 1.18;
- diabetes → 1.13.
Current tobacco use deserves its own comment: these patients not only have a higher risk of ulceration, but also a reduced rate of healing, a reduced effect of pharmacotherapy for ulceration, and a higher risk of complications such as perforation.
Duodenal ulcers
It is estimated that about 6–15% of Western people have duodenal ulcers. This number decreased during 1960 to 1980 and has stayed steady since; the fall is thought to reflect eradication and better hygiene with respect to H. pylori. Over the past 30 years, the rate of death, hospitalisation and need for physician visits for duodenal ulcers has decreased by more than 50%, and because pharmacotherapy can eradicate H. pylori, the recurrence of a duodenal ulcer after a first episode has decreased by more than 80%.
Duodenal ulcers occur mostly in the first portion of the duodenum (95%), and more than 90% of them lie in the first 3 cm of the pylorus. Most have a diameter of less than 1 cm, while some reach 3–6 cm and are called giant ulcers; they are sharply demarcated, their base mostly shows eosinophilic necrosis, and the surrounding tissue is fibrotic. Duodenal ulcers are mostly not malignant. A gastric ulcer, by contrast, differs enough in this respect that a biopsy is advised to exclude malignancy.
Gastric ulcers
Gastric ulcers tend to occur in elderly and male patients, mostly in the sixth decade of life. They are less frequent than duodenal ulcers, which may be because an asymptomatic ulcer becomes symptomatic only in its complicated forms; autopsy studies suggest an equal incidence of duodenal and gastric ulcers. A benign gastric ulcer is mostly located distal to the junction between the antrum and the acid-secreting mucosa, and is rarely found in the fundus.
Benign gastric ulcer is mainly due to one of two processes. H. pylori infection is one, usually accompanied by antral degeneration and atrophy. NSAID use is the other, and it produces a chronic active gastritis with the typical signs of chemical gastropathy: foveolar hyperplasia, edema of the lamina propria, and epithelial regeneration in the absence of H. pylori.
Acid production and mucosal defense
The majority of duodenal and gastric ulcers are related to H. pylori infection and NSAID use, and these causes act by shifting the balance between acid production and mucosal defence. In duodenal ulcers, the stomach produces more acid and the duodenum produces less bicarbonate. In gastric ulcers, the output of acid is reduced in most cases, but at the same time the mucosal defence is altered.
There are four types of gastric ulcer:
- type I → ulcers in the body of the stomach, with low acid production;
- type II → ulcers in the body combined with a duodenal ulcer, with acid over-secretion;
- type III → ulcers within 3 cm of the pylorus, with high acid production, mostly accompanied by a duodenal ulcer;
- type IV → ulcers in the cardia, with low acid production.