Gastritis describes a group of conditions with one thing in common: inflammation of the lining of the stomach. The inflammation of gastritis is most often the result of infection with the same bacterium that causes most stomach ulcers. Injury, regular use of certain pain relievers and drinking too much alcohol also can contribute to gastritis.
Gastritis may occur suddenly (acute gastritis), or it can occur slowly over time (chronic gastritis). 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.
Gastritis can be caused by irritation due to excessive alcohol use, chronic vomiting, stress, or the use of certain medications such asaspirin or other anti-inflammatory drugs. It may also be caused by any of the following:
- Helicobacter pylori (H. pylori): A bacteria that lives in the mucous lining of the stomach; without treatment, the infection can lead toulcers, and in some people, stomach cancer.
- Pernicious anemia: A form of anemia that occurs when the stomach lacks a naturally occurring substance needed to properly absorb and digest vitamin B12
- Bile reflux: A backflow of bile into the stomach from the bile tract (that connects to the liver and gallbladder)
- Infections caused by bacteria and viruses
Acute gastritis has a number of causes, including certain drugs; alcohol; bile; ischemia; bacterial, viral, and fungal infections; acute stress (shock); radiation; allergy and food poisoning; and direct trauma. The common mechanism of injury is an imbalance between the aggressive and the defensive factors that maintain the integrity of the gastric lining (mucosa).
Acute erosive gastritis can result from the exposure to a variety of agents or factors. This is referred to as reactive gastritis. These agents/factors include nonsteroidal anti-inflammatory medications (NSAIDs), alcohol, cocaine, stress, radiation, bile reflux, and ischemia. The gastric mucosa exhibits hemorrhages, erosions, and ulcers. NSAIDs, such as aspirin, ibuprofen, and naproxen, are the most common agents associated with acute erosive gastritis. This results from both oral and systemic administration of these agents, either in therapeutic doses or in supratherapeutic doses.
Because of gravity, the inciting agents lie on the greater curvature of the stomach. This partly explains the development of acute gastritis distally on or near the greater curvature of the stomach in the case of orally administered NSAIDs. However, the major mechanism of injury is the reduction in prostaglandin synthesis. Prostaglandins are chemicals responsible for maintaining mechanisms that result in the protection of the mucosa from the injurious effects of the gastric acid. Long-term effects of such ingestions can include fibrosis and stricture.
Bacterial infection is another cause of acute gastritis. The corkscrew-shaped bacterium called H pylori is the most common cause of gastritis. Complications result from a chronic infection rather than from an acute infection. The prevalence of H pylori in otherwise healthy individuals varies depending on age, socioeconomic class, and country of origin. The infection is usually acquired in childhood. In the Western world, the number of people infected with H pylori increases with age.
Evidence of H pylori infection can be found in 20% of individuals younger than 40 years and in 50% of individuals older than 60 years. How the bacterium is transmitted is not entirely clear. Transmission is likely from person to person through the oral-fecal route or through the ingestion of contaminated water or food. This is why the prevalence is higher in lower socioeconomic classes and in developing countries. H pylori is associated with 60% of gastric ulcers and 80% of duodenal ulcers.
H pylori gastritis typically starts as an acute gastritis in the antrum, causing intense inflammation, and over time, it may extend to involve the entire gastric mucosa resulting in chronic gastritis.
The acute gastritis encountered with H pylori is usually asymptomatic. The bacterium imbeds itself in the mucous layer, a protective layer that coats the gastric mucosa. It protects itself from the acidity of the stomach through the production of large amounts of urease, an enzyme that catalyzes the breakdown of urea to the alkaline ammonia and carbon dioxide. The alkaline ammonia neutralizes the gastric acid in the immediate vicinity of the bacterium conferring protection.
H pylori also has flagella that enable it to move and help it to penetrate the mucous layer so that it comes into contact with gastric epithelial cells. It also has several adhesion molecules that help it to adhere to these cells. It produces inflammation by activating a number of toxins and enzymes that activate IL-8, which eventually attracts polymorphs and monocytes that cause acute gastritis.
Antigen-presenting cells activate lymphocytes and other mononuclear cells that lead to chronic superficial gastritis. The infection is established within a few weeks after the primary exposure to H pylori. It produces inflammation via the production of a number of toxins and enzymes. The intense inflammation can result in the loss of gastric glands responsible for the production of acid. This is referred to as atrophic gastritis. Consequently, gastric acid production drops. The virulence genotype of the microbe is an important determinant for the severity of the gastritis and the formation of intestinal metaplasia, the transformation of gastric epithelium. This transformation can lead to gastric cancer.
Reactive gastropathy is the second most common diagnosis made on gastric biopsy specimens after H pylori gastritis. This entity is believed to be secondary to bile reflux and was originally reported after partial gastrectomy (Billroth I or II). It is now considered to represent a nonspecific response to a variety of other gastric irritants.
Helicobacter heilmanii is a gram-negative, tightly spiraled, helical-shaped organism with 5-7 turns. The prevalence of H heilmanii is extremely low (0.25-1.5%). The source of H heilmanii infection is unclear, but animal contact is thought to be the means of transmission.
Tuberculosis is a rare cause of gastritis, but an increasing number of cases have developed because of patients who are immunocompromised. Gastritis caused by tuberculosis is generally associated with pulmonary or disseminated disease.
Secondary syphilis of the stomach is a rare cause of gastritis.
Phlegmonous gastritis is an uncommon form of gastritis caused by numerous bacterial agents, including streptococci, staphylococci, Proteus species, Clostridium species, and Escherichia coli. Phlegmonous gastritis usually occurs in individuals who are debilitated. It is associated with a recent large intake of alcohol, a concomitant upper respiratory tract infection, and AIDS. Phlegmonous means a diffuse spreading inflammation of or within the connective tissue. In the stomach, it implies infection of the deeper layers of the stomach (submucosa and muscularis). As a result, purulent bacterial infection may lead to gangrene.
Phlegmonous gastritis is rare. The clinical diagnosis is usually established in the operating room, as these patients present with an acute abdominal emergency requiring immediate surgical exploration. Without appropriate therapy, it can progress to peritonitis and death.
Viral infections can cause gastritis. Cytomegalovirus (CMV) is a common viral cause of gastritis. It is usually encountered in individuals who are immunocompromised, including those with cancer, immunosuppression, transplants, and AIDS. Gastric involvement can be localized or diffuse.
Fungal infections that cause gastritis include Candida albicans and histoplasmosis. Gastric phycomycosis is another rare lethal fungal infection. The common predisposing factor is immunosuppression. C albicans rarely involves the gastric mucosa. When isolated in the stomach, the most common locations tend to be within a gastric ulcer or an erosion bed. It is generally of little consequence. Disseminated histoplasmosis can involve the stomach. The usual presenting clinical feature is bleeding from gastric ulcers or erosions on giant gastric folds.
Parasitic infections are rare causes of gastritis. Anisakidosis is caused by a nematode that embeds itself in the gastric mucosa along the greater curvature. Anisakidosis is acquired by eating contaminated sushi and other types of contaminated raw fish. It often causes severe abdominal pain that subsides within a few days. This nematode infection is associated with gastric fold swelling, erosions, and ulcers.
Ulcero-hemorrhagic gastritis is most commonly seen in patients who are critically ill. Ulcero-hemorrhagic gastritis is believed to be secondary to ischemia related to hypotension and shock or to the release of vasoconstrictive substances, but the etiology is often unknown. The gastric mucosa reveals multiple petechiae, mostly in the fundus and body, or exhibits a diffusely hemorrhagic pattern. The gross pathology may resemble that of NSAID- or other ingestion-induced gastritis, except that the location of injury is different. This form of gastritis can be life-threatening if the patient experiences hemorrhaging and may even require emergency gastrectomy.
Microscopic evidence of acute gastritis can be seen in patients with Crohn disease, though clinical manifestations are rare (occurring in only about 2-7% of patients with Crohn disease). Focally enhancing gastritis is now recognized as a condition seen in both Crohn disease and ulcerative colitis.
Eosinophilic gastritis is often seen in conjunction with eosinophilic gastroenteritis but can be associated with various disorders, including food allergies (eg, cow milk, soy protein), collagen vascular diseases, parasitic infections, gastric cancer, lymphoma, Crohn disease, vasculitis, drug allergies, and H pylori infections. An eosinophilic infiltrate is seen involving the gastric wall or epithelium.
Symptoms of gastritis are
- indigestion (burning pain in upper abdomen or “pit” of the stomach),
- nausea or vomiting,
- pain in the upper abdomen.
Although your doctor is likely to suspect gastritis after talking to you about your medical history and performing an exam, you may also have tests to pinpoint the exact cause. Tests may include:
- Tests for H. pylori. Your doctor may recommend tests to determine whether you have the bacterium H. pylori. Which type of test you undergo depends on your situation. H. pylori may be detected in a blood test, in a stool test or by a breath test. For the breath test, you drink a small glass of clear, tasteless liquid that contains radioactive carbon. H. pylori bacteria break down the test liquid in your stomach. Later, you blow into a bag, which is then sealed. If you’re infected with H. pylori, your breath sample will contain the radioactive carbon.
- Using a scope to examine your upper digestive system (endoscopy). During endoscopy, your doctor passes a flexible tube equipped with a lens (endoscope) down your throat and into your esophagus, stomach and small intestine. Using the endoscope, your doctor looks for signs of inflammation. If a suspicious area is found, your doctor may remove small tissue samples (biopsy) for laboratory examination. A biopsy can also identify the presence of H. pylori in your stomach lining.
- X-ray of your upper digestive system. Sometimes called a barium swallow or upper gastrointestinal series, this series of X-rays creates images of your esophagus, stomach and small intestine to look for abnormalities. To make the ulcer more visible, you swallow a white, metallic liquid (containing barium) that coats your digestive tract.
The safest treatment is to avoid substances that trigger gastritis symptoms.
- Almost all health-care professionals would recommend this as the first step in preventing gastritis.
- First, the patient has to identify the triggers of gastritis.
- Most people are aware of their triggers before seeking medical care.
- If a person does not know what triggers their gastritis, a health-care professional can assist them in determining the triggers.