Gastritis is inflammation of the stomach lining. Duodenitis is inflammation of the duodenum (the first part of the small intestine), which is located just below your stomach. Both gastritis and duodenitis have the same causes and treatments.
Both conditions may occur in men and women of all ages. The conditions may be acute or chronic. The acute forms come on suddenly and last for a short time. The chronic forms may progress slowly and last for months or years. The conditions are curable and generally don’t cause any long-term complications
The most common cause of gastritis and duodenitis is a bacterium called Helicobacter pylori (H. pylori). Large amounts of the bacteria invading your stomach or small intestine can cause inflammation.
H. pylori can be transferred from person to person. It can also be transmitted through contaminated food and water, although this is uncommon in the United States. According to the National Digestive Diseases Information Clearinghouse, approximately 20 to 50 percent of people in the United States may be infected with H. pylori. In comparison, up to 80 percent of people in developing countries are infected with the bacteria.
Other common causes of gastritis and duodenitis include the long-term use of certain medications, such as aspirin, ibuprofen, or naproxen, or drinking too much alcohol.
Less common causes include:
- Crohn’s disease (inflammation of the digestive tract)
- an autoimmune condition (when the body makes antibodies that attack the cells lining the stomach) resulting in atrophic gastritis (destruction of stomach lining)
- bile reflux (when bile flows from the duodenum into the stomach)
- having certain viral infections — such as herpes simplex virus — along with a weak immune system
- traumatic injury to your stomach or small intestine
- being placed on a breathing machine
- extreme stress caused by major surgery, severe body trauma, shock
- ingesting caustic substances or poisons (strong substances that can burn or corrode your tissues if you swallow them)
- excessive cigarette smoking
- radiation therapy for cancer
- chemotherapy for cancer