GastritisGastritis is inflammation of the stomach lining.  It can occur suddenly (acute) or gradually (chronic). Chronic gastritis occurs in two out of every 10,000 people, whereas acute gastritis is more common, occurring in eight out of every 1,000 people

CausesGastritis can be caused by many factors, including infection, injury, certain drugs, and disorders of the immune system.

1-Infections with bacteria, viruses, or fungi can cause gastritis. Worldwide, the most common cause of gastritis is infection with Helicobacter pylori bacteria. Viral 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.

2-Erosive gastritis results from irritants such as drugs, especially aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs. Crohn's 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. Erosive gastritis can develop suddenly but more commonly develops slowly, usually in people who are otherwise healthy.

3-Acute stress gastritis, actually 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 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 or to impairment of the stomach lining's ability to protect and renew itself.

4-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.

5-Postgastrectomy gastritis occurs &is thought to result when surgery impairs blood flow to the stomach lining or exposes the stomach lining to an excessive amount of bile

6-Atrophic gastritis causes the stomach lining to become very thin 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) &with Helicobacter pylori bacteria.

7-Eosinophilic gastritis may result from an allergic reaction to an infestation with roundworms. In other cases, the cause is unknown. In this type of gastritis, eosinophils accumulate in the stomach wall.

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

9- lymphocytic gastritis, lymphocytes (another type of white blood cell) accumulate in the stomach wall and other organs. This lymphocyte accumulation also occurs in celiac sprue (a malabsorptive disorder), but the cause is frequently unknown

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

Nausea and intermittent vomiting can result from erosive gastritis, radiation gastritis, Ménétrier's 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.

Ulcers can develop with several types of gastritis, especially acute stress gastritis, erosive gastritis, and radiation gastritis. Ulcers may bleed, causing a person to vomit blood (hematemesis) or pass tarry black stools (melena). Acute stress gastritis may lead to bleeding from ulcers within a few days after an illness or injury, whereas bleeding tends to develop more slowly in the case of erosive gastritis or radiation gastritis. Persistent bleeding can lead to symptoms of anemia, including fatigue, weakness, and light-headedness. 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's 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's 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 B 12 , allowing the B 12 to be absorbed and used in the production of red blood cells). A small percentage of people with atrophic gastritis develop a condition called metaplasia, in which cells lining the stomach change and become precancerous. In an even smaller percentage of people, metaplasia leads to stomach cancer.

DiagnosisA doctor suspects gastritis when a person has upper abdominal discomfort or 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, an examination of the stomach using an endoscope may be needed. If necessary, the doctor can perform a biopsy (removal of a tissue sample for examination under a microscope) of the stomach lining.

TreatmentRegardless 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 .

For mild symptoms, taking antacids, which neutralize acid that has already been produced and released in the stomach, is often sufficient. However, antacids have to be taken several times a day and often produce diarrhea or constipation.

Drugs that reduce acid production include histamine-2 (H 2 ) blockers and proton pump inhibitors. H 2 blockers are usually more effective than antacids in relieving symptoms,

and many people find them far more convenient. Proton pump inhibitors are prescribed when the strongest treatment is needed. When infection is a part of gastritis, antibiotics are also prescribed.

Doctors may prescribe sucralfate, which helps to prevent irritation. When gastritis leads to ulceration that perforates the stomach wall, immediate surgery is usually needed

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. The coxibs (COX-2 inhibitors such as celecoxib) are less likely to irritate the stomach lining than the older NSAIDs, but studies have shown that coxibs appear to increase the risk of heart attack and stroke with long-term use. Therefore, caution should be taken with use of coxibs.

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 is often 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. Blood transfusions may actually make bleeding worse. 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 measur

There is no cure for postgastrectomy gastritis or atrophic gastritis. People with anemia resulting from decreased absorption of vitamin B 12 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's disease. There is no effective drug treatment