Gastritis

Gastritis isn't one disease but a group of conditions, all of which are characterized by inflammation of the lining of your stomach. Commonly, the inflammation results from infection with the same bacterium that causes most stomach ulcers. Yet other factors — including traumatic injury and regular use of certain pain relievers — also can contribute to gastritis.
In spite of the many conditions associated with gastritis, the signs and symptoms of the disease are very similar: A burning pain in your upper abdomen and occasionally, bloating, belching, nausea or vomiting.
In some cases, gastritis can lead to ulcers and an increased risk of stomach cancer. For most people, however, gastritis isn't serious and improves quickly with treatment.


The signs and symptoms of gastritis, which are often relatively mild and short-lived, include:
A gnawing or burning ache or pain (indigestion) in your upper abdomen that may become either worse or better when you eat
Nausea
Vomiting
Loss of appetite
Belching or bloating
A feeling of fullness in your upper abdomen after eating
Weight loss
Gastritis that occurs suddenly (acute gastritis) usually results in the classic combination of nausea and burning pain or discomfort in your upper abdomen, whereas chronic gastritis, which develops gradually, is more likely to cause a dull pain and a feeling of fullness or loss of appetite after a few bites of food. For many people, though, chronic gastritis causes no problems at all.
Occasionally, gastritis may cause stomach bleeding, but it's rarely severe unless there's also ulceration of your stomach lining. Bleeding in your stomach can cause you to vomit blood or pass black, tarry stools and may require immediate medical care.
Because gastritis is one of many common digestive problems with similar signs and symptoms, it's easy to confuse with other conditions, including:


Gastroenteritis. Also called stomach flu, gastroenteritis usually results from a viral infection of your intestines. Signs and symptoms include diarrhea, abdominal cramps, and nausea or vomiting, as well as indigestion. Symptoms of gastroenteritis often resolve within a day or two, whereas the discomfort of gastritis may be ongoing.

Heartburn. This painful, burning sensation behind your breastbone usually occurs after a meal. It develops when stomach acid backs up into your esophagus, the tube that connects your throat to your stomach. Heartburn can also lead to a sour taste and the sensation of partially digested food re-entering your mouth.

Stomach ulcers. If a gnawing or burning pain in your stomach is persistent and severe, you may have an ulcer. Stomach (peptic) ulcers are open sores that develop on the inside lining of the stomach. The most prominent symptom is pain, which is frequently worse at night or when your stomach is empty. Gastritis and stomach ulcers share some of the same causes — especially H. pylori infection — and the one may be a precursor to the other.

Nonulcer dyspepsia. Commonly referred to as indigestion, nonulcer dyspepsia is a functional disorder and not necessarily related to a particular disease. The exact cause isn't known, but stress and overindulging in fried, spicy or fatty foods can aggravate or trigger the upper abdominal pain, bloating, belching and nausea that characterize the condition.

Causes
Your stomach — a hollow, muscular sac — sits in the upper left corner of your abdomen, just under your rib cage. The typical adult stomach is around 10 inches long and can expand to hold about 1 gallon of food and liquid. When your stomach is empty, its tissues fold in on themselves, a bit like a closed accordion. As your stomach fills and expands, the folds gradually disappear.
Your stomach processes and stores food, which it gradually releases into your small intestine. When food arrives from your esophagus, a muscular ring at the joining of your esophagus and stomach (lower esophageal sphincter) relaxes to let it in. Your stomach walls, lined with layers of powerful muscles, then begin churning the food, mixing it into smaller and smaller pieces. At the same time, glands in the wall of your stomach pump out gastric juices — including enzymes and stomach acids — that help break food down further.
One of these, hydrochloric acid, is so caustic that it can dissolve iron nails. Your stomach's tissues are protected from this corrosive acid by the mucous-bicarbonate barrier — a layered buffering system in which bicarbonate regulates the stomach's acid-alkaline balance, and mucous provides a thick, sticky coating for the stomach walls.