Duodenitis (Small Intestine) Causes, Symptoms and Treatment

What is duodenitis?

Duodenitis is inflammation of the first part of the small intestine which is known as the duodenum. It is a relatively common condition that often co-exists with gastritis which is inflammation of the stomach. The same causes of gastritis tends to lead to duodenitis. It may also be complicated with peptic ulcers, and these open sores tend to be more common in the duodenum than the stomach.

Causes of Duodenitis

The two main causes of duodenitis revolves around the same causes for gastritis. H.pylori infection and the excessive use of NSAIDs are the two main causes of gastritis. Another factor in duodenitis is excessive stomach acid which eventually seeps into the duodenum. It is important to understand how the stomach and duodenum handles this acid.

Read more on gastritis.

Acid in the Duodenum

The acid produced by the stomach is highly corrosive as this is needed for digestion. However, it also has the potential to digest living tissue. The stomach is able to prevent this as it has a mucus barrier that coats the inner stomach wall. When the stomach contents are sufficiently digested, it is passed into the duodenum along with the acid.

Various mechanisms have to quickly take effect to prevent damage to the duodenum. Firstly the duodenum has a mucus barrier similar to the stomach. This alkali mucus is secreted by tiny glands in the duodenal wall. Large amounts of water are also secreted into the duodenum by the pancreas along with digestive enzymes. This fluid will dilute the stomach acid.

Another mechanism that assists is bile from the gallbladder which is secreted into the duodenum. The bile helps to also neutralize the stomach acid. Despite these mechanisms the duodenum cannot withstand the stomach acid for long periods. It is further compromised if one of more of these mechanisms are impaired in some way.


H.pylori is a relatively unique bacterium. It is able to withstand acid by secreting substances around it which neutralizes the acid in the immediate vicinity. The bacteria can then reach the stomach or duodenal wall and damage the lining. This also compromises the mucus barrier to some extent which allows stomach acid and digestive enzymes to further irritate the lining.


A number of drugs can play a role in duodenum and gastritis but non-steroidal anti-inflammatory drugs (NSAIDs) are more often implicated. These drugs are easily available over the counter and are often used for long periods of time. The substances in NSAIDS can affect the production of mucus which helps form a barrier between the acid and the inner lining.

Excessive Acid

Sometimes the stomach produces large amounts of acid. This acid eventually seeps into the duodenum. However, the duodenum may not be able to cope with large amounts of acid and this can then lead to injury of the duodenal wall. Increased acid production may be due to a host of causes including the use of stimulants like nicotine, certain illicit drugs, medication and stress.

Signs and Symptoms

The signs and symptoms of duodenitis is largely the same as gastritis and most people are unable to differentiate between these conditions. The severity of symptoms can also depend on whether duodenitis is erosive where open sores form in the duodenal wall, or non-erosive where the duodenal wall is inflamed but there are no ulcers.

Abdominal Pain

Abdominal pain is one of the most common symptoms. It is typically felt in the upper middle region of the abdomen where the duodenum is located. Often the pain is more severe in erosive gastritis due to the exposed inner tissue. The nature and severity of the pain can vary from a dull gnawing ache to a sharp pain. It may worsen a short while after eating and in the early hours of the morning.

Read more on upper middle abdominal pain.

Nausea and Vomiting

Nausea is another common symptom and sometimes it may present with vomiting. The nausea is due to the irritation of the duodenum and may correlate with the pain. In severe instances it may elicit vomiting but this is not common. If there is any bleeding from an ulcer, fresh blood or dried blood (like coffee grounds) may be seen in the vomitus.

Change in Appetite

There is very often a change in appetite with duodenal ulcers. Most of the time this is a loss of appetite. A person may also report bloating where there is a sensation of fullness after a few bites. The loss of appetite is largely driven by the fact that pain worsens after eating. It may eventually lead to weight loss.

Other Signs and Symptoms

  • Excessive belching due to an accumulation of gas.
  • Difficulty sleeping as a result of the pain.
  • Dark tarry stools In the event of bleeding ulcers.


The symptoms of duodenitis may be triggered or worsened by certain factors. This includes drinking caffeinated beverages like coffee, consuming alcohol, eating spicy meals as well as greasy meals, certain processed or preserved foods, with prolonged gum chewing and with cigarette smoking. These factors are not a cause of duodenitis but just exacerbating factors.

Treatment of Duodenitis


It is important to confirm the diagnosis with an upper gastrointestinal endoscopy where the inflammation can be observed through a tiny camera with a light at the end. The treatment for duodenitis is largely the same as it is for gastritis.

  • Antacids may provide short term relief by neutralizing stomach acid. These are the most commonly used medication since it is largely available over-the-counter.
  • Acid-suppressing medication is the main drug of choice. By reducing the acid production it allows the duodenal wall to heal. However, this may not be sufficient on its own at times.
  • Antibioitics are necessary if H.pylori infection can be confirmed. This eradication therapy may require several courses of antibiotics.
  • Coating agents like bismuth subsalicylate helps to line the duodenal wall. This helps the duodenum to heal by reducing contact between the acid and inner lining.

Dietary and lifestyle factors are also important in the management of duodenitis. This includes stopping smoking, avoiding trigger foods like spicy meals and minimizing alcohol intake.

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