by Jason Wasserman MD PhD FRCPC
December 16, 2022

What is Helicobacter gastritis?

Helicobacter gastritis is an infection in the stomach by the bacteria Helicobacter pylori. It is the most common cause of gastritis in many parts of the world.

What are the symptoms of Helicobacter gastritis?

Common symptoms of Helicobacter gastritis include nausea, vomiting, bloating, and abdominal pain. The pain may be worse after eating. Some people with Helicobacter gastritis experience no symptoms and the infection is discovered incidentally (by accident) when tests are performed for other reasons.

How is the diagnosis of Helicobacter pylori made?

The diagnosis of Helicobacter gastritis can be made after a biopsy is performed during a procedure called an upper endoscopy. This procedure uses a small camera to look inside the stomach. The biopsy is then sent to a pathologist who examines the tissue under the microscope. Other non-invasive tests include a breast urea test and stool antigen test.

What does Helicobacter pylori gastritis look like under the microscope?

Infection of the stomach by Helicobacter pylori causes inflammation of the tissue that covers the inside of the stomach. Pathologists describe the inflammation in the stomach as chronic active gastritis because it includes both chronic inflammatory cells such as plasma cells and lymphocytes and active inflammatory cells such as neutrophils. Round collections of immune cells called lymphoid follicles may be seen in long-standing infections. The cells on the inside of the stomach can also change to look more like the cells normally found on the inside of the small intestine. This is called intestinal metaplasia. Intestinal metaplasia in the stomach is important because it increases the risk of developing a type of stomach cancer called adenocarcinoma over time.

Immunohistochemistry for Helicobacter pylori

Pathologists can perform a test called immunohistochemistry to see the Helicobacter pylori bacteria on the inside surface of the stomach. When this test is performed, the bacteria look brown or red and they may be round or comma-shaped.

How is Helicobacter gastritis treated?

Helicobacter gastritis should be treated with antibiotics. If left untreated, Helicobacter infection can cause stomach ulcers. Untreated Helicobacter infection also increases the risk of developing cancer in the stomach.