What Is Gastritis?
Gastritis is the inflammation of the stomach’s lining that develops due to bacteria, stomach ulcers, increased intake of painkillers, and excess alcohol drinking.
Gastritis can occur suddenly (acute gastritis) or slowly over time (chronic gastritis). In some cases, gastritis can result in ulcers and stomach cancers. In some people, gastritis may not occur seriously and improves with treatment.
What Is Autoimmune Gastritis?
Autoimmune gastritis is a specific form of atrophic gastritis (a chronic state of gastritis). As the name implies, atrophic gastritis causes atrophy of a part of the stomach lining called oxyntic mucosa, having oxyntic cells (parietal cells).
Atrophic gastritis is often caused by Helicobacter pylori infection. This bacterium survives in the high acidic state of the gastric mucosa and causes chronic inflammation. The other terms for autoimmune gastritis are autoimmune metaplastic gastritis or chronic autoimmune atrophic gastritis.
Autoimmune gastritis is a chronic inflammatory disease where the destruction of parietal cells of the corpus and fundus of the stomach takes place. In this condition, the immune system mistakenly attacks and destroys the parietal cells in the stomach.
The immune system wears the stomach’s protective barrier and interferes with the absorption of several vital vitamins such as vitamin B12, folate, and iron. Along with this, pepsin-producing cells are destroyed in the stomach.
Parietal cells are epithelial cells located in the stomach's corpus and fundus and produce gastric acid and intrinsic factors in the body. This intrinsic factor helps in the absorption of vitamin B12 in the body. If a person faces difficulty absorbing vitamin B12, the person is known to develop pernicious anemia soon.
As the condition progresses, some of the normal cells in the stomach lining get replaced with abnormal intestinal-type cells, causing intestinal metaplasia. Intestinal metaplasia is a precancerous lesion and increases the risk of developing gastric adenocarcinoma.
What Is the Cause of Autoimmune Gastritis?
Autoimmune gastritis often occurs as an autoimmune disorder. The immune system mistakenly attacks the acid-producing machinery (H+ or K+ or ATPase proton pump) inside the parietal cells. People with other autoimmune conditions are prone to develop autoimmune gastritis soon. More than one family member may remain affected with autoimmune gastritis in some cases. Some studies suggest that this condition may occur inherited in an autosomal dominant manner.
Few studies suggest that food intolerance caused by gut imbalance can cause autoimmune reactions. An imbalanced gut impairs the body's ability to absorb nutrients, regulate blood sugar, and store fat. A leaky gut can also cause autoimmune gastritis.
A leaky gut is a condition where the gut lining remains damaged and cannot process food properly. The food particles are not fully digested and leak into the bloodstream. So the immune system considers these processes as potential threats which cause autoimmune reactions.
In autosomal dominant conditions, the affected person only needs a mutation in one copy of the responsible gene in each cell. In a few cases, the affected person inherits a mutation from their affected parent. Other patients may also present with new (de novo) mutations in the gene. These cases often occur in people without a family history of autoimmune gastritis. The affected person has a fifty percent chance of passing the altered gene to their child during each pregnancy.
What Are the Symptoms of Autoimmune Gastritis?
Autoimmune gastritis does not show any obvious signs and symptoms in some cases. But some people may experience nausea, vomiting, abdominal pain, and a feeling of fullness in the abdomen after eating.
The affected person may also experience pain and discomfort in the stomach's upper part (fundus) because the acid-secreting parietal cells remain concentrated in this region. Some patients may experience chest pain, tiredness, tinnitus or ringing in the ears, dizziness, lightheadedness, and heart palpitations.
Autoimmune gastritis can also cause impaired absorption of vitamin B12 resulting in other vitamin deficiencies such as folate and iron in the body. People lacking vitamin B12 are prone to develop pernicious anemia, where the body does not have adequate healthy red blood cells.
Vitamin B12 deficiency can also result in nerve damage, and the affected person also experiences confusion, unsteadiness while walking, and tingling or numbness in the arms or legs.
How to Diagnose Autoimmune Gastritis?
Autoimmune gastritis is not generally suspected until characteristic signs and symptoms are shown in the body. Additional testing is done to confirm the diagnosis. Biopsy of the affected tissue is obtained through endoscopy. The doctor inserts a flexible thin tube called an endoscope with a light and camera down the stomach to collect a tissue sample in this procedure. The blood work checks the presence of parietal cell antibodies in the blood.
How to Treat Autoimmune Gastritis?
The treatment is generally focused on treating vitamin B12 and iron deficiency. If pernicious anemia persists during diagnosis, the affected person needs vitamin B12 injections. Alternative iron therapy can be followed when diet and oral iron supplements do not improve iron levels.
People affected with autoimmune gastritis should monitor their vitamin B12 and iron levels for the rest of their lifetimes. The affected person can take periodic intravenous iron to increase iron stores.
The affected individuals can also take a daily dose of oral Ferrous Glycine Sulfate to meet daily iron requirements. In some cases, regular endoscopy is recommended due to their increased risk of developing certain types of cancer.
What Is the Diet to Be Followed in People Affected With Autoimmune Gastritis?
People affected with autoimmune gastritis might take a diet rich in vitamin B12 to prevent further complications developed due to vitamin B12 deficiency. The dietary sources of vitamin B12 are clams, beef, eggs, fortified cereals, milk, yogurt, and fatty fish.
What Is the Prognosis of the People Affected With Autoimmune Gastritis?
The long-term outlook or prognosis of the people affected with autoimmune gastritis varies due to their increased risk of developing pernicious anemia, gastric polyps, and gastric adenocarcinoma. The significant risk factors for the development of gastric cancer in autoimmune gastritis are:
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Pernicious anemia.
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The severity of atrophy.
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Intestinal metaplasia.
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Duration of the disease.
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Age above 50 years old.
Thus, early diagnosis and proper treatment of the disease reduce mortality.
Conclusion:
Autoimmune gastritis is not generally suspected until characteristic signs and symptoms are shown in the body. Autoimmune gastritis does not show any obvious signs and symptoms in some cases. But some people may experience nausea, vomiting, abdominal pain, and a feeling of fullness in the abdomen after eating.
Autoimmune gastritis can also cause impaired absorption of vitamin B12 resulting in other vitamin deficiencies such as folate and iron in the body. People lacking vitamin B12 are prone to develop pernicious anemia, where the body does not have adequate healthy red blood cells. The treatment is generally focused on treating vitamin B12 and iron deficiency. The affected person can take periodic intravenous iron to increase iron stores. People affected with autoimmune gastritis might also need to take a diet rich in vitamin B12 to prevent further complications developed due to vitamin B12 deficiency.
