Diseases: Stomach and Duodenum: Gastritis
The term “gastritis” is commonly used by doctors and the public alike to explain the brief episodes of transient upper abdominal pain, nausea and vomiting which frequently affect much of the population. Gastritis, however, is usually not the cause of these upsets and, in its strictest sense, gastritis is a diagnosis made by a pathologist when he sees evidence of inflammation and damage to the stomach lining in a biopsy specimen taken at endoscopy. True gastritis may be of acute onset in which case symptoms are common, or else it may be a chronic, often silent problem.
Acute gastritis may produce no symptoms but can be associated with short-lived dyspepsia, lack of appetite, nausea or vomiting. It can occasionally be severe enough to cause gastrointestinal bleeding with melena or hematemesis (see above). The most common cause is ingestion of aspirin or other non-steroidal anti-imflammatory drugs (NSAIDs). It can also occur during the early stages of infection with the bacteria, Helicobacter pylori “HP.” Most cases resolve by themselves, but endoscopy and biopsy may be required to exclude other conditions such as peptic ulcer disease or cancer. At endoscopy the inner lining of the stomach (mucosa) may appear swollen, reddened and inflamed. There may be small, shallow erosions (breaks in the surface lining) or even tiny areas of bleeding from the mucosa. These changes are usually confined to the stomach rather than the duodenum. Other tests, such as blood tests, x-rays and scans are usually not necessary for diagnosis unless an alternative condition is suspected during investigation. Often no specific therapy is required but short courses of antacids, acid suppressing drugs or drugs for nausea may be necessary. Aspirin or NSAIDs should be stopped if possible.
Chronic gastritis is extremely common and usually results from infection with HP. In the USA and other developed countries, infection with HP becomes more common with increasing age and up to 40-50% of fifty year old people are infected. In underdeveloped countries the infection is much more common and in some areas up to 90% of the population is infected by adulthood. In the vast majority of cases stomach biopsies show mild chronic gastritis but usually this produces no symptoms and the patient is unaware of the infection. A small percentage, however, will develop peptic ulcer disease because of the infection (see below). At present, however, there is little evidence that patients with symptoms of indigestion but no abnormality at endoscopy will benefit from treatment of the infection.
Much less commonly, chronic gastritis may occur when the body’s own immune system attacks the acid secreting cells of the stomach lining. This is a form of “auto-immune” disease and the reasons why it occurs are unknown. It mostly affects middle-aged or elderly women, and usually causes no symptoms. The inflammation of the gastric lining continues over many years until the stomach’s ability to secrete acid is lost (achlorhydria). Also lost is the ability to secrete intrinsic factor which is necessary for binding and absorption of the important vitamin, B12. Deficiency of vitamin B12 eventually leads to a condition known as pernicious anemia. The problem is often discovered at this stage, when the patient presents with tiredness, anemia, or rarely, symptoms in the limbs such as numbness or tingling. The diagnosis is confirmed by blood tests which show evidence of anemia, a low level of vitamin B12 and characteristic abnormalities in the shape of the red blood cells when examined under a microscope. Further investigations are usually undertaken by a specialist and treatment of pernicious anemia consists of replacement of vitamin B12 by regular injections. Nothing can be done to restore acid secretion but there is little evidence that this impairs the body’s ability to digest and absorb food. There may be a small increase in the risk of stomach cancer in patients suffering from long-standing pernicious anemia.