Acute Gastritis

Gastritis is inflammation of the stomach lining.

• The inflammation can be caused by many factors, including infection, stress, injury, certain drugs, and disorders of the immune system.
• When symptoms of gastritis do occur, they include abdominal pain or discomfort and sometimes nausea or vomiting.
• Doctors often base the diagnosis on the person's symptoms, but sometimes they need to examine the stomach with a flexible viewing tube (upper endoscopy).
• Treatment is with drugs that reduce stomach acid.

The stomach lining resists irritation and can usually withstand very strong acid. Nevertheless, in gastritis, the stomach lining becomes irritated and inflamed.

Gastritis is divided into two categories based on how severe it is:

• Erosive
• Nonerosive

Erosive gastritis is more severe than nonerosive gastritis. This form involves both inflammation and wearing away (erosion) of the stomach lining. The cells that produce mucus to protect the stomach lining from acid are missing or are damaged. Erosive gastritis typically develops suddenly (called acute erosive gastritis) but may develop slowly (called chronic erosive gastritis), usually in people who are otherwise healthy.

Nonerosive gastritis is characterized by changes in the stomach lining that range from wasting away (atrophy) of the stomach lining to transformation of stomach tissue into another type of intestinal tissue (metaplasia). Often, several types of white blood cells accumulate in the stomach and cause varying degrees of inflammation. The white blood cells may cause inflammation in the entire stomach or only in certain parts.

Causes of Gastritis

The specific types of gastritis are caused by many factors, including infection, stress, injury, certain drugs, and disorders of the immune system.

Erosive gastritis is caused by alcohol; stress; irritants such as drugs, especially aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs); Crohn disease; bacterial and viral infections; and the ingestion of corrosive substances. In some people, even a baby aspirin taken daily can injure the stomach lining. Less commonly, radiation, viral infections (such as cytomegalovirus), and direct injuries (such as by the insertion of a nasogastric tube) can cause erosive gastritis.

Nonerosive gastritiscan be caused by Helicobacter pylori infection.

Infectious gastritis not caused by Helicobacter pylori is rare.

Viral gastritis or fungal gastritis may develop in people who have had a prolonged illness or an impaired immune system, such as those who have AIDS or cancer or those who take immunosuppressant drugs.

Acute stress gastritis, a form of erosive gastritis, is caused by a sudden illness or injury. The injury may not even be to the stomach. For example, extensive skin burns, head injuries, and injuries involving major bleeding are typical causes. Exactly why serious illness can lead to gastritis is not known but may be related to decreased blood flow to the stomach, an increase in the amount of acid in the stomach, and/or to impairment of the stomach lining's ability to protect and renew itself.

Radiation gastritis can occur if radiation is delivered to the lower left side of the chest or upper abdomen, where it can irritate the stomach lining.

Postgastrectomy gastritis occurs in people who have had part of their stomach surgically removed (a procedure called partial gastrectomy). The inflammation usually occurs where tissue has been sewn back together. Postgastrectomy gastritis is thought to result when surgery impairs blood flow to the stomach lining or exposes the stomach lining to an excessive amount of bile (the greenish yellow digestive fluid produced by the liver).

Atrophic gastritis causes the stomach lining to become very thin (atrophic) and to lose many or all of the cells that produce acid and enzymes. This condition can occur when antibodies attack the stomach lining (termed autoimmune metaplastic atrophic gastritis). Atrophic gastritis can also occur in some people who are chronically infected with H. pylori bacteria. It also tends to occur in people who have had part of their stomach removed.

Eosinophilic gastritis may result from an allergic reaction to an infestation with roundworms, but usually the cause is unknown. In this type of gastritis, eosinophils (a type of white blood cell) accumulate in the stomach wall.

Menetrier disease, a rare disorder whose cause is unknown, is a type of gastritis in which the stomach wall develops thick, large folds and fluid-filled cysts. The disease may be due to an abnormal immune reaction and has also been associated with Helicobacter pylori infection.

Acute Gastritis

Gastritis usually causes no symptoms. When symptoms do occur, they vary depending on the cause and may include pain or discomfort or nausea or vomiting, problems that are often simply referred to as indigestion (dyspepsia).

Chronic Gastritis

Nausea and intermittent vomiting can result from erosive gastritis, radiation gastritis, Ménétrier disease, and lymphocytic gastritis.

Dyspepsia can occur, especially with erosive gastritis, radiation gastritis, postgastrectomy gastritis, and atrophic gastritis. Very mild dyspepsia also occurs with acute stress gastritis.

Complications of gastritis

Acute stress gastritis may lead to bleeding within a few days after an illness or injury, whereas bleeding tends to develop more slowly in the case of chronic erosive gastritis or radiation gastritis. If bleeding is mild and slow, people may have no symptoms or may notice only black stool (melena), caused by the black color of digested blood. If bleeding is more rapid, people may vomit blood or pass blood in their stool. Persistent bleeding can lead to symptoms of anemia, including fatigue, weakness, and light-headedness.

Gastritis can lead to stomach ulcers (gastric ulcers), which may cause the symptoms to get worse. If an ulcer goes through (perforates) the stomach wall, stomach contents may spill into the abdominal cavity, resulting in inflammation and usually infection of the lining of the abdominal cavity (peritonitis) and sudden worsening of pain.

Some complications of gastritis are slow to develop. The scarring and narrowing of the stomach outlet that can result from gastritis, especially from radiation gastritis and eosinophilic gastritis, can cause severe nausea and frequent vomiting.

In Ménétrier disease, fluid retention and swelling of the tissues (edema) may occur because of loss of protein from the inflamed stomach lining. About 10% of people with Ménétrier disease develop stomach cancer some years later.

Postgastrectomy gastritis and atrophic gastritis may cause symptoms of anemia, such as fatigue and weakness, because of decreased production of intrinsic factor (a protein that binds vitamin B12, allowing the B12 to be absorbed and used in the production of red blood cells).

A small percentage of people with atrophic gastritis develop metaplasia. In an even smaller percentage of people, metaplasia leads to stomach cancer.

Diagnosis of Gastritis

• Upper endoscopy

A doctor suspects gastritis when a person has upper abdominal discomfort, pain, or nausea. Tests usually are not needed. However, if the doctor is uncertain of the diagnosis, or if symptoms do not resolve with treatment, the doctor may do upper endoscopy. During upper endoscopy, a doctor uses an endoscope (a flexible viewing tube) to examine the stomach and some of the small intestine. If necessary, the doctor can do a biopsy (removal of a tissue sample for examination under a microscope) of the stomach lining.

Treatment of Gastritis

• Drugs that reduce acid production and antacids
• Sometimes antibiotics that treat H. pylori infection
• Treatments to stop bleeding

Regardless of the cause of gastritis, symptoms can be relieved by taking drugs that neutralize or reduce the production of stomach acid and by discontinuing drugs that cause symptoms.

Drugs for gastritis

For mild symptoms, taking antacids, which neutralize acid that has already been produced and released in the stomach, is often sufficient. Almost all antacids can be purchased without a doctor's prescription and are available in tablet or liquid form. Antacids include aluminum hydroxide (which can cause constipation), magnesium hydroxide (which can cause diarrhea), and calcium carbonate. Because antacids can interfere with the absorption of many different drugs, people who take other drugs should consult a pharmacist before taking antacids.

Acid-reducing drugs include histamine-2 (H2) blockers and proton pump inhibitors. H2 blockers are usually more effective than antacids in relieving symptoms, and many people find them far more convenient. Doctors most often prescribe proton pump inhibitors for gastritis associated with bleeding.

Doctors may prescribe sucralfate, which helps coat and heal the stomach and also prevents irritation.
When gastritis is caused by H. pylori infection, antibiotics are also prescribed.

Erosive gastritis

People with erosive gastritis must avoid taking drugs that irritate the stomach lining (such as NSAIDs). Some doctors prescribe proton pump inhibitors or misoprostol to help protect the stomach lining.

Acute stress gastritis

Most people with acute stress gastritis recover fully when the underlying illness, injury, or bleeding is controlled. However, 2% of people in intensive care units have heavy bleeding from acute stress gastritis, which can be fatal. Therefore, doctors try to prevent acute stress gastritis after a major illness, major injury, or severe burn. Drugs that reduce acid production are commonly given after surgery and to people in most intensive care units to prevent acute stress gastritis. These drugs are also used to treat any ulcers that form.

For people with heavy bleeding from acute stress gastritis, a wide variety of treatments have been used. Few of these treatments, however, improve the outcome. Bleeding points can be temporarily heat-sealed (cauterized) during an endoscopy, but bleeding often starts again if the underlying illness persists. If bleeding continues, the entire stomach may have to be removed as a lifesaving measure.

Other types of gastritis

There is no cure for postgastrectomy gastritis or atrophic gastritis. People with anemia resulting from decreased absorption of vitamin B12 that occurs with atrophic gastritis must take supplemental injections of the vitamin for the rest of their lives.

Corticosteroids or surgery may be needed to relieve a blocked stomach outlet caused by eosinophilic gastritis.
Removing part or all of the stomach may cure Ménétrier disease. There is no effective drug treatment.