Pernicious Anemia: Definition, Symptoms, Causes, Diagnosis, Treatment and Prevention

Vitamin B12 helps the body make healthy red blood cells and helps keep nerve cells healthy.

Pernicious anemia is defined as a type of vitamin B12 deficiency that results from altered absorption of vitamin B-12 due to the lack of a substance known as intrinsic factor (IF) produced by the lining of the stomach.

Pernicious anemia is a condition caused by too little vitamin B12 in the body. It is a form of anemia due to vitamin B12 deficiency.

This vitamin is found in foods of animal origin, such as meat, fish, eggs, milk and other dairy products.

The most common cause of pernicious anemia is the loss of stomach cells that create an intrinsic factor. Intrinsic factor helps the body absorb vitamin B12 in the intestine. The loss of parietal cells may be due to destruction by the body’s own immune system.

Pernicious anemia can cause permanent damage to the nerves and other organs if it lasts a long time without treatment. It also increases the risk of developing stomach cancer .

How is it diagnosed?

Pernicious anemia is diagnosed using a family history and medical history, a physical examination, and diagnostic tests and procedures. And it is easy to deal with pills or injections of vitamin B12, as well as changes in the diet. You need a treatment for life.

Complications caused by untreated pernicious anemia may be reversible with treatment.

Doctors do not know how to prevent pernicious anemia caused by the immune system that destroys stomach cells.

However, eating foods rich in vitamin B12 and folic acid can help prevent vitamin B12 deficiency caused by poor diet.

It is advised to make the blood disorders, hemorrhages and anemia charts once a year.

Pernicious anemia and red blood cells

Anemia is a condition in which the body does not have a sufficient amount of red blood cells or hemoglobin . Hemoglobin is present in red blood cells and is important for transporting oxygen to all tissues of the body.

Anemia in men and women

In men, anemia is typically defined as a hemoglobin level of less than 13.5 grams / 100 ml, while in women, a hemoglobin level of less than 12.0 grams / 100 ml is considered to be indicative of anemia.

These definitions may vary slightly depending on the source and the laboratory reference used. Pernicious is a term that means destructive, harmful or deadly.

Anemia can be the result of interruptions in the production of red blood cells or hemoglobin, as well as a greater destruction of red blood cells or blood loss.

Pernicious anemia is a disease in which large, immature, nucleated cells (megaloblasts, which are precursors to red blood cells) circulate in the blood and do not function as blood cells.

It is a disease caused by decreased absorption of vitamin B-12 due to the lack of intrinsic factor (IF) in the gastric mucosa.

It was called “pernicious” because before it was known that vitamin B-12 could treat anemia, most people who developed the disease died from it.

Anemia and vitamin B-12

Pernicious anemia is due to the inability to absorb vitamin B-12 (also known as cobalamin or Cbl) from the gastrointestinal tract.

Humans get vitamin B-12 from products of animal origin, both meat and dairy products are dietary sources of vitamin B-12.

The body can store vitamin B-12 for a long time, so the inadequate dietary intake should persist for years before reaching a true vitamin B-12 deficiency.

Therefore, the symptoms of pernicious anemia do not usually appear for years. While pernicious anemia is diagnosed more frequently in adults with an average age of 60 years, a rare, congenital type of pernicious anemia has been described.

As with other causes of anemia, symptoms related to decreased oxygen carrying capacity of the blood may include fatigue and shortness of breath.

Vitamin B-12 deficiency also interferes with nervous system function and symptoms due to nervous system damage may be evident even before anemia is discovered.

Pernicious anemia is more common in Caucasians of northern European descent than in other racial groups. Pernicious anemia is also called Biermer’s or Addison’s anemia.

Common signs and symptoms

Symptoms of vitamin B12 deficiency, which are observed in pernicious anemia are:

  • Feeling tired and weak
  • Tingling and numbness in hands and feet.
  • A red tongue, soft and bright.

Sometimes, anemias are subclassified according to the size and microscopic appearance of red blood cells. In this sense, pernicious anemia is a form of megaloblastic disease

As discussed above, true pernicious anemia is the result of an autoimmune condition that affects the absorption of vitamin B-12 in the diet, resulting in a deficiency of vitamin B-12.

Deficiency of vitamin B-12 from any cause, including pernicious anemia, will cause anemia and neurological symptoms. Because the body has large reserves of vitamin B-12, a deficiency takes many years to establish.

Vitamin B-12 deficiency affects the nervous system, leading to a variety of symptoms. Sometimes, these may be evident before symptoms related to anemia.

Neurological symptoms vary and can be nonspecific (meaning that these are symptoms that can be caused by a number of different conditions).

Feelings of numbness, tingling, weakness, lack of coordination, clumsiness, memory problems and personality changes may occur. Both sides of the body are usually affected and the legs are usually more affected than the arms.

A severe deficiency can cause more serious neurological symptoms, including severe weakness, spasticity, paraplegia, and fecal and urinary incontinence.

Why are your symptoms?

The symptoms of anemia are due to the reduced ability of the blood to carry oxygen. Shortness of breath, fatigue, dizziness and pale skin can occur with anemia.

In anemia, the heart is under stress because it has to work harder to release enough oxygen to the tissues of the body.

This can cause heart murmurs , rapid heartbeat, arrhythmias, an enlarged heart (cardiomegaly) or even heart failure . It is important to keep in mind that not all people who are deficient in vitamin B-12 and neurological symptoms will also have anemia.

Finally, pernicious anemia is sometimes diagnosed in a patient without symptoms. In these cases, it is usually found incidentally when ordering blood tests for another reason.

Causes of pernicious anemia

Pernicious anemia is considered an autoimmune disease, in which the body’s own immune system mistakenly damages its own tissues.

It is believed that the lower absorption of vitamin B-12 from the gastrointestinal tract in pernicious anemia is due to the presence of an autoantibody against intrinsic factor (FI), a protein produced in the stomach that is necessary for the absorption of vitamin B- 12 .

Normally, vitamin B-12 binds to the intrinsic factor in the stomach, and this facilitates its absorption by the small intestine later in the digestive process.

Along with the autoimmune process that attacks the FI protein and reduces FI levels in stomach secretions, another autoimmune reaction also occurs against the cells lining the stomach, resulting in a form of inflammation known as chronic atrophic gastritis.

Pernicious anemia is sometimes associated with other autoimmune diseases such as Graves’ disease, Hashimoto’s thyroiditis and vitiligo (depigmentation or whitening of the skin areas).

Is pernicious anemia the same as vitamin B-12 deficiency anemia?

No, pernicious anemia is a form of vitamin B-12 deficiency that results from the autoimmune process described above.

However, other causes of vitamin B-12 deficiency can also produce the same signs and symptoms as pernicious anemia.

Other possible causes of vitamin B-12 deficiency include surgical removal of the stomach or a portion of the stomach (total or partial gastrectomy), other gastrointestinal diseases such as celiac disease or Crohn’s disease .

Also infections of the gastrointestinal tract, prolonged use of acid and poor nutrition.

What is the treatment for pernicious anemia and vitamin B-12 deficiency?

The symptoms of pernicious anemia and vitamin B-12 deficiency can be treated by replenishing the supply of vitamin B-12 in the body.

If a condition other than pernicious anemia is responsible for vitamin B-12 deficiency, treatment should also be directed to the underlying condition. Symptoms of vitamin B-12 deficiency may improve after a few days of medical treatment.

Vitamin B-12 is usually given as an intramuscular injection. An injection of 1000 micrograms (1 mg) of vitamin B-12 is usually given every day for a week, followed by 1 mg every week for four weeks and then 1 mg every month thereafter.

Alternative treatments for pernicious anemia include high doses of oral vitamin B-12, since there is a less effective absorption system for vitamin B-12 in the intestine that does not require the presence of IF.

However, the oral dose required for this type of therapy (1 to 2 mg / day) is more than 200 times greater than the minimum daily requirement of vitamin B-12 for adults and is significantly higher than that available in most patients. standard multivitamins and B-12 supplements.

Nasal spray and sublingual preparations (under the tongue) of vitamin B-12 are also available and are under investigation.


The autoimmune process that causes pernicious anemia can not be prevented.

Vitamin B-12 deficiency, which is caused by conditions such as other gastrointestinal diseases and gastrointestinal surgery, is preventable only to the extent that these causative conditions are preventable.

Vitamin B-12 is derived from animals (eg, meat, fish, poultry, milk sources, but vitamin B-12 deficiency in vegetarians or vegans can be prevented through the use of oral vitamin B supplements). 12

An oral dose of 100-200 micrograms (mcg) taken weekly is sufficient. Pregnant and lactating women who are vegetarian or vegan should take a B-12 supplement and inform their doctors that they are vegetarian or vegan.