Peptic duodenitis

What is peptic duodenitis?

Peptic duodenitis is a non-cancerous change that happens in the duodenum. It is caused by increased acid production in the stomach. The extra acid spills into the duodenum where it damages the cells in the mucosa. The damage causes abdominal pain which is worse when the stomach is empty and better after a meal. If left untreated, peptic duodenitis can lead to ulcers and bleeding in the duodenum.

The small bowel

The small bowel is a part of the digestive system. Another name for the small bowel is the small intestine. The small bowel is a long tube that starts at the stomach and ends at the colon. It is divided into three parts: duodenum, jejunum, and ileum. The duodenum is the shortest part of the small bowel. It connects to the stomach on the right side of the body just below the ribs.

Food that we eat enters the stomach where it is mixed and broken down by strong acids made by cells inside the stomach. When this is complete, the digested food moves into the small bowel. The purpose of the small bowel is to absorb nutrients from the food and transport those nutrients into the body.

The inside of the duodenum is lined by epithelial cells that are specially designed to absorb nutrients from the food we eat. These specialized cells form a barrier called an epithelium. Below the epithelium is a thin layer of tissue called the lamina propria. This tissue contains many small blood vessels which support the epithelial cells.

duodenum normal

Mucosa is a word pathologists use to describe the epithelium and lamina propria together. The mucosa in the small bowel grows in a way that creates long finger-like projections of tissue called villi. These villi allow the small bowel to have a large surface area in a relatively small space.

Below the mucosa are specialized cells that connect to form round structures called Brunner’s glands. These glands produce substances that protect the epithelial cells from the strong acid coming from the stomach.

What causes increased stomach acid production?

The most common cause of increased acid production is an infection of the stomach by a bacteria called Helicobacter. Other common causes of increased acid production are prolonged use of non-steroidal anti-inflammatory drugs (NSAIDs), smoking, and chronic kidney disease.

How do pathologists make this diagnosis?

The diagnosis of peptic duodenitis is made after a pathologist examines a tissue sample from the inside of the duodenum under the microscope. The tissue sample is removed in a procedure called a biopsy. A tissue sample should also be taken from inside of the stomach to look for Helicobacter. The biopsy is usually performed after the patient is sedated and a camera called an endoscope is inserted into the small bowel.

Pathologists look for the following features to make this diagnosis:

  • Increased numbers of neutrophils in the mucosa – Neutrophils are specialized immune cells that fight off infections and help the body heal after an injury. In peptic duodenitis, an increased number of neutrophils are seen in both the epithelium and in the lamina propria. Pathologists describe this as acute inflammation.
  • Erosion – Erosion is a word pathologists use to describe an injury that damages the cells on the surface of a tissue. In the duodenum, erosion means a loss of epithelial cells.
  • Foveolar metaplasia – Foveolar cells are normally found on the inside of the stomach. They are specially designed to protect tissue from the damaging effects of acid. Foveolar metaplasia means that the cells normally found in the epithelium of the duodenum have been replaced by foveolar cells. The duodenum undergoes this change in order to protect itself from the extra acid spilling into the duodenum from the stomach.
  • Brunner gland hyperplasia – Brunner glands are designed to protect the duodenum from acid. The number of Brunner glands increases in response to the extra acid entering the duodenum. Pathologists describe this change as hyperplasia.

Your pathologist may also order special stains or immunohistochemistry to look for Helicobacter in the tissue sample from the duodenum or the stomach.

by Jason Wasserman MD PhD FRCPC (updated July 26, 2021)
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